subject:(Laminar flames)

Louisiana State University

1. Naralasetti, Veerendra. Micro Combustion of Primary Reference Fuels in Narrow Heated Channels.

Degree: MSME, Heat Transfer, Combustion, 2018, Louisiana State University

URL: https://digitalcommons.lsu.edu/gradschool_theses/4786

► Conventional fuel testing machines like CFR engines require large quantities of fuel. The current study seeks to overcome this limitation by introducing an alternative… (more)

Subjects/Keywords: micro-combustion; PRF; laminar flames

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Naralasetti, V. (2018). Micro Combustion of Primary Reference Fuels in Narrow Heated Channels. (Masters Thesis). Louisiana State University. Retrieved from https://digitalcommons.lsu.edu/gradschool_theses/4786

Chicago Manual of Style (16^th Edition):

Naralasetti, Veerendra. “Micro Combustion of Primary Reference Fuels in Narrow Heated Channels.” 2018. Masters Thesis, Louisiana State University. Accessed April 12, 2021. https://digitalcommons.lsu.edu/gradschool_theses/4786.

MLA Handbook (7^th Edition):

Naralasetti, Veerendra. “Micro Combustion of Primary Reference Fuels in Narrow Heated Channels.” 2018. Web. 12 Apr 2021.

Vancouver:

Naralasetti V. Micro Combustion of Primary Reference Fuels in Narrow Heated Channels. [Internet] [Masters thesis]. Louisiana State University; 2018. [cited 2021 Apr 12]. Available from: https://digitalcommons.lsu.edu/gradschool_theses/4786.

Council of Science Editors:

Naralasetti V. Micro Combustion of Primary Reference Fuels in Narrow Heated Channels. [Masters Thesis]. Louisiana State University; 2018. Available from: https://digitalcommons.lsu.edu/gradschool_theses/4786

University of Illinois – Chicago

2. Kalvakala, Ramachandraiah Krishna C. On Soot Reduction Using Oxygenated Combustion in High Pressure Counterflow Flames.

Degree: 2018, University of Illinois – Chicago

URL: http://hdl.handle.net/10027/23340

► Reduction of NOx and soot emissions from combustion systems has been a major driver for combustion research in recent years. A promising approach for reducing… (more)

▼ Reduction of NOx and soot emissions from combustion systems has been a major driver for combustion research in recent years. A promising approach for reducing soot in non-premixed flames is based on simultaneously using an O2-enriched oxidizer stream and a N2-diluted fuel stream. The effectiveness of this approach is due to the fact that it modifies the stoichiometric mixture fraction (st) without significantly altering the adiabatic flame temperature. The present work involves a computational study on oxygenated non-premixed counterflow flames burning different small hydrocarbon fuels (ethylene, propene and propane) at atmospheric and high pressures (ethylene). The computational model employs a validated reaction mechanism with 197 species and about 5000 reactions for gas-phase chemistry, and a fairly detailed soot model. Results focus on the effect of oxygenation, fuel unsaturation, and pressure on the flame structure, soot precursors and soot emissions. At a given pressure, as st is increased, there is a significant reduction in acetylene and PAHs formation, and with additional soot oxidation in the post flame region, it leads to a nearly non-sooting flame. The presence of double bond (C=C) leads to higher soot emissions, with the amount of soot formed being the highest in propene flames, followed by ethylene flames, and then propane flames. Dominant reaction paths are analyzed to examine the relative roles of double bond, hydrodynamics and changes in flame structure on PAHs and soot emissions. The drastic reduction in PAHs and soot formation can be attributed to both the hydrodynamic and flame structure effects. While the oxygenated combustion in reducing soot is also effective at higher pressures (1-8 atm), the effect of increasing pressure at a fixed st is to increase the PAHs and soot emissions. Advisors/Committee Members: Aggarwal, Suresh K (advisor), Brezinsky, Kenneth (committee member), Lynch, Patrick (committee member), Aggarwal, Suresh K (chair).

Subjects/Keywords: Combustion; Laminar Flames; Oxygenated; Soot Emissions

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kalvakala, R. K. C. (2018). On Soot Reduction Using Oxygenated Combustion in High Pressure Counterflow Flames. (Thesis). University of Illinois – Chicago. Retrieved from http://hdl.handle.net/10027/23340

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kalvakala, Ramachandraiah Krishna C. “On Soot Reduction Using Oxygenated Combustion in High Pressure Counterflow Flames.” 2018. Thesis, University of Illinois – Chicago. Accessed April 12, 2021. http://hdl.handle.net/10027/23340.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kalvakala, Ramachandraiah Krishna C. “On Soot Reduction Using Oxygenated Combustion in High Pressure Counterflow Flames.” 2018. Web. 12 Apr 2021.

Vancouver:

Kalvakala RKC. On Soot Reduction Using Oxygenated Combustion in High Pressure Counterflow Flames. [Internet] [Thesis]. University of Illinois – Chicago; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10027/23340.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kalvakala RKC. On Soot Reduction Using Oxygenated Combustion in High Pressure Counterflow Flames. [Thesis]. University of Illinois – Chicago; 2018. Available from: http://hdl.handle.net/10027/23340

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

3. Dasgupta, Adhiraj Kishore. Numerical Simulation of AxiSymmetric Laminar Diffusion Flames with Soot.

Degree: 2015, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/27357

► Detailed numerical modeling of combustion phenomena, soot formation, and radi- ation is an active area of research. In this work a general-purpose, pressure-based, finite volume… (more)

▼ Detailed numerical modeling of combustion phenomena, soot formation, and radi- ation is an active area of research. In this work a general-purpose, pressure-based, finite volume code for modeling laminar diffusion flames has been incorporated into the CFD code OpenFOAM. The code uses a mixture-averaged model for the calculation of transport coefficients, and can be used to perform detailed modeling of multi-dimensional laminar flames using realistic molecular transport, and with detailed chemical mechanisms containing hundreds of chemical species and reac- tions. Two soot models have been incorporated into the code: a semi-empirical two-equation model, as well as a detailed Method of Moments with Interpolative Closure (MOMIC). An emission-only, optically-thin radiation model has also been included in the code to account for the radiative heat loss, and sophisticated radia- tion models with detailed calculations of spectral properties and radiative intensity have also been included. The flame code showed excellent scalability on massively distributed, high-performance computer systems. The code has been validated by modeling four axisymmetric, co-flowing laminar diffusion flames, and the results have been found to be mostly within experimental uncertainty, and comparable to results reported in the literature for the same and similar configurations. A number of parametric studies to study the effects of detailed gas-phase chemistry, soot models and radiation have also been performed on these flame configurations. It has been found that the flames considered in this work are all optically thin, and so the simple, emission-only, optically-thin radiation model can be used to model these flames with good accuracy and a reasonable computational effort. In particular, the detailed radiation models increase the computational cost by two orders of magnitude, and thus their applicability in a detailed calculation may be limited. It was found that the two-equation soot model used in conjunction with a gas- phase mechanism that adequately describes the combustion of C2 hydrocarbons produces results in close agreement with experimental data for a 1-bar ethylene-air flame, a 10 bar methane-air flame, as well as an ethane-air flame at 10 bar. The detailed MOMIC soot model requires the use of a larger, more detailed gas-phase chemical mechanism containing polycyclic aromatic hydrocarbons (PAH) with four rings, and thus the computational cost associated with the MOMIC soot model is significantly higher. The detailed model was used to model the flames, and computed soot levels were within a factor of two of the experimental values, which is typically considered good agreement considering the complex physics involved. The last flame studied using both the soot models was a N2 -diluted ethylene-air flame, in which the predicted values of major gas-phase species were seen to be close to the experimental values, but the soot levels were off by an order of magnitude. Notwithstanding the lack of agreement with measurements for this flame,… Advisors/Committee Members: Daniel Connell Haworth, Dissertation Advisor/Co-Advisor, Daniel Connell Haworth, Committee Chair/Co-Chair, Stephen R Turns, Committee Member, Robert John Santoro, Committee Member, Philip John Morris, Special Member.

Subjects/Keywords: soot; laminar flames; OpenFOAM; diffusion flames; CFD modeling

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dasgupta, A. K. (2015). Numerical Simulation of AxiSymmetric Laminar Diffusion Flames with Soot. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/27357

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Dasgupta, Adhiraj Kishore. “Numerical Simulation of AxiSymmetric Laminar Diffusion Flames with Soot.” 2015. Thesis, Penn State University. Accessed April 12, 2021. https://submit-etda.libraries.psu.edu/catalog/27357.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Dasgupta, Adhiraj Kishore. “Numerical Simulation of AxiSymmetric Laminar Diffusion Flames with Soot.” 2015. Web. 12 Apr 2021.

Vancouver:

Dasgupta AK. Numerical Simulation of AxiSymmetric Laminar Diffusion Flames with Soot. [Internet] [Thesis]. Penn State University; 2015. [cited 2021 Apr 12]. Available from: https://submit-etda.libraries.psu.edu/catalog/27357.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Dasgupta AK. Numerical Simulation of AxiSymmetric Laminar Diffusion Flames with Soot. [Thesis]. Penn State University; 2015. Available from: https://submit-etda.libraries.psu.edu/catalog/27357

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

4. Yang, Sheng. Chemical Kinetics and Propagation Dynamics of Laminar and Turbulent Flames .

Degree: PhD, 2017, Princeton University

URL: http://arks.princeton.edu/ark:/88435/dsp01ks65hf859

► Recognizing the fundamental and practical importance of premixed flames in combustion research, the present dissertation consists of a series of studies on the chemical kinetics… (more)

▼ Recognizing the fundamental and practical importance of premixed flames in combustion research, the present dissertation consists of a series of studies on the chemical kinetics and propagation dynamics of both laminar and turbulent flames. First, starting with the relatively simple but fundamental configuration of the laminar unstretched flames propagating in quiescent environments, the laminar flame speeds of hydrogen flames have been measured, to validate and improve the corresponding kinetic models. Based on the updated model, the analysis on the kinetic networks shows the opposing role of the reaction H+O2(+M)=HO2(+M) under different conditions. Then, the dynamics of laminar flame propagation have been studied; on one hand, in a local perspective, the collision of flames has been studied with the emphasis on the dynamics and flow pattern of the flame corners generated. It is demonstrated that the flame corners are controlled by the interaction of preferential diffusion and kinematic restoration, generating the vortices of considerable strength relative to the turbulent eddies. On the other hand, in a global perspective, we have looked into the evolution of cellular instabilities, including hydrodynamic and diffusional-thermal modes. The influence of preferential diffusion as well as thermal expansion, on the onset of the instability and acceleration of flame propagation, has been studied. Next, recognizing the knowledge of laminar flames, the turbulent flames have been studied thereafter recognizing the effect of hydrodynamic instability. A scaling analysis has been performed on the interaction between the growth of hydrodynamic cells and the wrinkles by the turbulent eddies, within different regimes in the turbulent flame regime diagram. The turbulent flame speeds have been measured experimentally, and subsequently compared with their scaling law under various conditions with the diffusionally neutral mixtures. Furthermore, we shall demonstrate the essential role of the molecular preferential diffusion in the structure and propagation of turbulent flames. It is demonstrated that due to preferential diffusion, the mixtures, whose concentrations are near or beyond the conventional flammability limits, can be rendered to burn strongly in turbulence, with distinctive finger-shape structures on the flame surfaces. Finally, the key remarks in this dissertation have been summarized, with recommendations for further explorations. Advisors/Committee Members: Law, Chung K (advisor).

Subjects/Keywords: chemical kinetics; flame dynamics; flame instability; laminar flames; turbulent flames

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Yang, S. (2017). Chemical Kinetics and Propagation Dynamics of Laminar and Turbulent Flames . (Doctoral Dissertation). Princeton University. Retrieved from http://arks.princeton.edu/ark:/88435/dsp01ks65hf859

Chicago Manual of Style (16^th Edition):

Yang, Sheng. “Chemical Kinetics and Propagation Dynamics of Laminar and Turbulent Flames .” 2017. Doctoral Dissertation, Princeton University. Accessed April 12, 2021. http://arks.princeton.edu/ark:/88435/dsp01ks65hf859.

MLA Handbook (7^th Edition):

Yang, Sheng. “Chemical Kinetics and Propagation Dynamics of Laminar and Turbulent Flames .” 2017. Web. 12 Apr 2021.

Vancouver:

Yang S. Chemical Kinetics and Propagation Dynamics of Laminar and Turbulent Flames . [Internet] [Doctoral dissertation]. Princeton University; 2017. [cited 2021 Apr 12]. Available from: http://arks.princeton.edu/ark:/88435/dsp01ks65hf859.

Council of Science Editors:

Yang S. Chemical Kinetics and Propagation Dynamics of Laminar and Turbulent Flames . [Doctoral Dissertation]. Princeton University; 2017. Available from: http://arks.princeton.edu/ark:/88435/dsp01ks65hf859

King Abdullah University of Science and Technology

5. Mahuthannan, Ariff Magdoom. Experimental Investigation of the Quenching Processes of Fast-Moving Flames.

Degree: Physical Science and Engineering (PSE) Division, 2020, King Abdullah University of Science and Technology

URL: http://hdl.handle.net/10754/664984

► The quenching of undesired flames by cold surfaces has been investigated for more than a century. The current quenching theory can predict simple configurations, this… (more)

▼ The quenching of undesired flames by cold surfaces has been investigated for more than a century. The current quenching theory can predict simple configurations, this is not the case for real environments such as fuel management systems. Flames are sensitive to numerous parameters, such as fuel, mixture fraction, pressure, temperature, flow properties, acoustics, radiation, and surface interactions. The effects of some of these parameters are very well documented but there is a lack of information regarding the effects of acoustics and flow. This dissertation work will focus on improving the understanding of flow effect on the quenching of premixed gaseous flames. First, the effect of apparent velocity on flame quenching was investigated for different fuels and equivalence ratios. An experimental facility is designed such that the apparent flame velocity at which the flame enters and propagates through the channel can be varied without changing the initial mixture condition. High-speed (15,000 frames per second (FPS)) Schlieren and dynamic pressure measurement were used to measure the apparent flame velocity and to assess the flame quenching, respectively. This study showed that the high-speed laminar flames are harder to quench compared to self-propagating and turbulent flames. A similar trend was obtained for all the conditions investigated, lean and stoichiometric methane-air, lean propane-air, and lean ethylene-air mixtures. Further investigation was carried out to understand the quenching of high-speed laminar flames. The flame propagation through the channel was investigated using Hydroxyl (OH) planar laser induced fluorescence (PLIF). This study showed that the OH intensity fell below the detection threshold in the later part of the channel when quenching is observed. Then, the influence of heat transfer was investigated using spatial and temporal evolution of the temperature in the quenching channel. A high-speed (10 kHz) filtered Rayleigh scattering (FRS) technique was used to measure the one-dimensional time-resolved temperature profile. Three different channel heights (H = 1.3, 1.5, 2.0 mm) were investigated. Based on the evolution of the temperature profile in the quenching channel, a new parameter was identified and the importance of its evolution on the flame quenching was discussed. Advisors/Committee Members: Lacoste, Deanna (advisor), Roberts, William Lafayette (committee member), Knio, Omar (committee member), Ruiz-Martinez, Javier (committee member), Moeck, Jonas P (committee member).

Subjects/Keywords: Flame quenching; Laminar flames; turbulent flames; High-speed flames; laser diagnostics; narrow channel

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mahuthannan, A. M. (2020). Experimental Investigation of the Quenching Processes of Fast-Moving Flames. (Thesis). King Abdullah University of Science and Technology. Retrieved from http://hdl.handle.net/10754/664984

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mahuthannan, Ariff Magdoom. “Experimental Investigation of the Quenching Processes of Fast-Moving Flames.” 2020. Thesis, King Abdullah University of Science and Technology. Accessed April 12, 2021. http://hdl.handle.net/10754/664984.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mahuthannan, Ariff Magdoom. “Experimental Investigation of the Quenching Processes of Fast-Moving Flames.” 2020. Web. 12 Apr 2021.

Vancouver:

Mahuthannan AM. Experimental Investigation of the Quenching Processes of Fast-Moving Flames. [Internet] [Thesis]. King Abdullah University of Science and Technology; 2020. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10754/664984.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mahuthannan AM. Experimental Investigation of the Quenching Processes of Fast-Moving Flames. [Thesis]. King Abdullah University of Science and Technology; 2020. Available from: http://hdl.handle.net/10754/664984

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Melbourne

6. Wiseman, Samuel. An optical study of sound generation in lean premixed combustion.

Degree: 2018, University of Melbourne

URL: http://hdl.handle.net/11343/217357

► This thesis presents an experimental and theoretical study of sound generation in lean, premixed, propane-air flames. Sound generation by axisymmetric, forced, laminar flames is investigated… (more)

▼ This thesis presents an experimental and theoretical study of sound generation in lean, premixed, propane-air flames. Sound generation by axisymmetric, forced, laminar flames is investigated first. The sound generated by the formation and consumption of separated pockets is determined. The second part of the thesis quantifies the capability of Flame Chemiluminescence Tomography (FCT) to directly study the flame dynamics responsible for sound generation. Suitable techniques are not yet available to acquire time-resolved, 3D measurements of entire turbulent flames. FCT is therefore investigated on non-axisymmetric, forced, laminar flames. Chemiluminescence imaging and microphone measurements are used to relate the acoustic pressure emitted by forced, laminar flames to the flame geometry at different phases of the forcing cycle. The formation and consumption of separated pockets is shown to be a significant source of sound. A model of sound generation by conical and spherical flame elements is presented, where the flame is treated as an infinitely-thin zone of heat generation. It is shown that increases in the flame displacement speed with increasing curvature is responsible for a significant increase in the amplitude of the radiated sound. The merging of the preheat and reaction zones of oppositely propagating flames that occurs in the terminal moments of both the formation and consumption of separated reactant pockets has previously been identified as a potentially significant source of combustion noise. However, in forced, laminar, lean, propane-air flames the sound produced by this merging is found to be small relative to the sound generated by negative flame stretch that occurs before opposite flames are within two thermal flame thicknesses of each other. To assess the capabilities of FCT, a single camera is used to acquire 36 equally-spaced, coplanar views of forced, premixed, non-axisymmetric, laminar flames at 100 phases of their forcing cycle. A Multiplicative Algebraic Reconstruction Technique (MART) algorithm is then used to reconstruct the time resolved chemiluminescence field using different numbers of equally-spaced views. Algorithms for measuring the flame surface area, the mean curvature, the normal component of the flame propagation velocity and the chemiluminescent flame thickness are demonstrated and the sensitivity of these measurements to the number of views used in the reconstruction is assessed. Less than 10 views may be sufficient to measure flame surface area, flame curvature and flame surface speed. However, at least 18 views appear to be required in order to obtain useful measurements of flame thickness.

Subjects/Keywords: forced flames; excited flames; laminar flames; premixed flames; combustion noise; flame noise; flame annihilation; flame chemiluminescence tomography; computed tomography of chemiluminescence; propane flames

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wiseman, S. (2018). An optical study of sound generation in lean premixed combustion. (Doctoral Dissertation). University of Melbourne. Retrieved from http://hdl.handle.net/11343/217357

Chicago Manual of Style (16^th Edition):

Wiseman, Samuel. “An optical study of sound generation in lean premixed combustion.” 2018. Doctoral Dissertation, University of Melbourne. Accessed April 12, 2021. http://hdl.handle.net/11343/217357.

MLA Handbook (7^th Edition):

Wiseman, Samuel. “An optical study of sound generation in lean premixed combustion.” 2018. Web. 12 Apr 2021.

Vancouver:

Wiseman S. An optical study of sound generation in lean premixed combustion. [Internet] [Doctoral dissertation]. University of Melbourne; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/11343/217357.

Council of Science Editors:

Wiseman S. An optical study of sound generation in lean premixed combustion. [Doctoral Dissertation]. University of Melbourne; 2018. Available from: http://hdl.handle.net/11343/217357

University of California – Berkeley

7. Murphy, Daniel Corrigan. The Measurement and Application of Electric Effects in Combustion.

Degree: Mechanical Engineering, 2015, University of California – Berkeley

URL: http://www.escholarship.org/uc/item/47s6w7dm

► The existence of interactions between flames and electric fields has been known for quite some time and has received experimental and theoretical study over the… (more)

▼ The existence of interactions between flames and electric fields has been known for quite some time and has received experimental and theoretical study over the years but remain an active topic of research in the combustion community. The present work specifically investigates the sensitivity of premixed flames electric fields. Prior work has demonstrated that electric fields may be used to enhance and control combustion, but full potential and range of applications for this effect have not been explored. Multiple theories have been presented to explain the process, but there is not yet a truly complete understanding of how electric fields fundamentally change the process of combustion. This work serves to explore new applications of electric-flame interactions and to provide experimental measurements to support the development of detailed theoretical models.Thermo-diffusive and acoustic instabilities in freely propagating flames can trigger the formation of wrinkled flames and turbulence, which may or may not be desirable in different scenarios. Electric fields present a means to interact with such instabilities either by generating direct hydrodynamic forces ('ionic wind') or by modifying the rate of combustion. Experiments performed on downward-propagating hydrocarbon flames have demonstrated that electric fields can be applied to excite or suppress existing instabilities and control the onset of turbulence. Numerical models following from these experiments indicate that subtle spatial variations in chemical reactivity can achieve similar control of inherently unstable flames.A practical limitation of combustion is the phenomenon of quenching, where heat losses to the surroundings extinguish a flame. The enhancement achieved by electric fields is shown to dramatically increase flame propagation speed and reduce quenching in methane-air flames, which may permit the miniaturization of combustion-based power generation systems. In the course of these experiments, flames were found to exhibit different behavior depending on the direction of the applied field. This result is consistent with a proposed model of ion transport in laminar flames, although the experiments have shown a greater degree of enhancement than predicted.Ultimately, modeling the electrical aspects of combustion should be based on detailed accounting of the ion species present in flames. To support the ongoing development of detailed ion-chemistry mechanisms, a non-intrusive microwave interferometer for use in shock tube studies of combustion kinetics was developed. This was used to measure the formation and consumption of free electrons in shock-induced combustion. The range of equivalence ratios tested and the variety of hydrocarbon fuels used provide a rich dataset. Comparison of these results to complementary chemical kinetics simulations have been used to validate proposed improvements to existing mechanisms.

Subjects/Keywords: Mechanical engineering; Combustion; Electric fields; Laminar flames; Microwave

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Murphy, D. C. (2015). The Measurement and Application of Electric Effects in Combustion. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/47s6w7dm

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Murphy, Daniel Corrigan. “The Measurement and Application of Electric Effects in Combustion.” 2015. Thesis, University of California – Berkeley. Accessed April 12, 2021. http://www.escholarship.org/uc/item/47s6w7dm.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Murphy, Daniel Corrigan. “The Measurement and Application of Electric Effects in Combustion.” 2015. Web. 12 Apr 2021.

Vancouver:

Murphy DC. The Measurement and Application of Electric Effects in Combustion. [Internet] [Thesis]. University of California – Berkeley; 2015. [cited 2021 Apr 12]. Available from: http://www.escholarship.org/uc/item/47s6w7dm.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Murphy DC. The Measurement and Application of Electric Effects in Combustion. [Thesis]. University of California – Berkeley; 2015. Available from: http://www.escholarship.org/uc/item/47s6w7dm

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Michigan

8. Xu, Fang. Soot growth in laminar premixed flames.

Degree: PhD, Chemical engineering, 1999, University of Michigan

URL: http://hdl.handle.net/2027.42/131820

► The objectives of the present investigation were to study soot processes in laminar premixed flames. Both experimental and computational methods were used: the experiments involved… (more)

▼ The objectives of the present investigation were to study soot processes in laminar premixed flames. Both experimental and computational methods were used: the experiments involved observations of the flame and soot properties of laminar premixed flames stabilized on flat-flame burners at atmospheric pressure, the computations involved predictions of flame structure using detailed mechanisms of transport and chemical kinetics as well as predictions of soot surface growth rate using existing mechanisms in the literature. The experiments considered soot-containing ethylene/air flames having fuel-equivalence ratios of 2.34 – 2.94 and soot-containing methane/oxygen flames having fuel-equivalence ratios of 2.20 – 2.60. The following properties were measured along the axes of the test flames: soot volume fractions, soot primary particle diameters, soot and gas temperatures, concentrations of major gas species, H atom concentrations, concentrations of condensable hydrocarbon species and gas velocities. Flame structure was predicted using the detailed chemical mechanisms of Frenklach and coworkers (1992) and Leung and Lindstedt (1995). Predictions of flame structure in the soot growth region were in good agreement with measurements. Prediction of H atom concentrations were also in good agreement with the measurements and showed that H atom was in local thermodynamic equilibrium. Present measurements were used to find soot surface growth rates and primary particle nucleation rates along the axes of the flames. These results were used to evaluate the Hydrogen-Abstraction/Carbon-Addition (HACA) soot growth mechanisms of Frenklach and coworkers (1995) and Colket and Hall (1994). The agreement between measured and predicted soot growth rates was excellent for both HACA mechanisms. These results imply that reduced soot surface growth rates with increasing residence time were mainly caused by reduced rates of surface activation due to reduced H atom concentrations as temperatures decrease from radiative heat losses; therefore, temperature reductions due to radiative heat losses from soot itself ultimately controls maximum soot concentrations in these flames. Advisors/Committee Members: Faeth, Gerard M. (advisor).

Subjects/Keywords: Flames; Laminar; Premixed; Soot Growth

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Xu, F. (1999). Soot growth in laminar premixed flames. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/131820

Chicago Manual of Style (16^th Edition):

Xu, Fang. “Soot growth in laminar premixed flames.” 1999. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/131820.

MLA Handbook (7^th Edition):

Xu, Fang. “Soot growth in laminar premixed flames.” 1999. Web. 12 Apr 2021.

Vancouver:

Xu F. Soot growth in laminar premixed flames. [Internet] [Doctoral dissertation]. University of Michigan; 1999. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/131820.

Council of Science Editors:

Xu F. Soot growth in laminar premixed flames. [Doctoral Dissertation]. University of Michigan; 1999. Available from: http://hdl.handle.net/2027.42/131820

University of Southern California

9. Veloo, Peter Surendran. Studies of the combustion characteristics of alcohols, aldehydes, and ketones.

Degree: PhD, Mechanical Engineering, 2011, University of Southern California

URL: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/620291/rec/6172

► The combustion characteristics of oxygenated C₁-C₄ hydrocarbons were investigated both experimentally and numerically in laminar premixed and non-premixed flames. These characteristics included laminar flame speeds… (more)

Subjects/Keywords: laminar flames; alcohols; aldehydes; ketones; flame propagation; flame extinction

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Veloo, P. S. (2011). Studies of the combustion characteristics of alcohols, aldehydes, and ketones. (Doctoral Dissertation). University of Southern California. Retrieved from http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/620291/rec/6172

Chicago Manual of Style (16^th Edition):

Veloo, Peter Surendran. “Studies of the combustion characteristics of alcohols, aldehydes, and ketones.” 2011. Doctoral Dissertation, University of Southern California. Accessed April 12, 2021. http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/620291/rec/6172.

MLA Handbook (7^th Edition):

Veloo, Peter Surendran. “Studies of the combustion characteristics of alcohols, aldehydes, and ketones.” 2011. Web. 12 Apr 2021.

Vancouver:

Veloo PS. Studies of the combustion characteristics of alcohols, aldehydes, and ketones. [Internet] [Doctoral dissertation]. University of Southern California; 2011. [cited 2021 Apr 12]. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/620291/rec/6172.

Council of Science Editors:

Veloo PS. Studies of the combustion characteristics of alcohols, aldehydes, and ketones. [Doctoral Dissertation]. University of Southern California; 2011. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/620291/rec/6172

Université Catholique de Louvain

10. Van Damme, Stefanie. Advanced biofuels : oxidation kinetics of methyl pentanoate and life cycle assessment of triacetin.

Degree: 2018, Université Catholique de Louvain

URL: http://hdl.handle.net/2078.1/198378

► Biofuels are a part of our current and future energy mix. Bioethanol and biodiesel are blend with our current fuels and despite the strong interest… (more)

▼ Biofuels are a part of our current and future energy mix. Bioethanol and biodiesel are blend with our current fuels and despite the strong interest in electric cars, liquid fuels are still needed for heavy transport and aviation. A biofuel is sustainble as less Green House Gases (GHG) are emitted by it use and production compared to fossil fuels and no hazardous molecules and particles are formed by its combustion. In this thesis two advanced biofuels are investigated: methyl pentanoate (MPE) and triacetin. Both are esters and MPE can be used in gasoline engines without any adjustment. While triacetin can be coproduced with biodiesel and can act as a fuel additive in diesel engines. The combustion kinetics of MPE are investigated in this work. Investigating which molecules are formed by its combustion. Premixed laminar flat flames with different equivalence ratios were stabilized on a Botha-Spalding burner at a pressure of 55 mbar. The mole fraction profiles of stable species were measured with GC-FID/TCD and the temperature of the flame with a fine wire thermocouple. Radiation losses during the temperature measurements were corrected with both the Electrical Compensation Method (ECM) and a Heat Transfer Method (HTM) method. The corrected temperature profiles obtained with the HTM were used for simulation of the laminar flat flames. A kinetic model for the oxidation of MPE, proposed by Dayma et al., is used for the simulations. The kinetic mechanism is composed of 206 species and 1792 reactions. The OpensMOKE software is used for the simulations. Overall a good fit between experimental and simulated mole fraction profiles was found for the rich and stoichiometric MPE flames. The performance of the mechanism for other combustion configuration is also assessed and in the end some improvements for the kinetic mechanism are suggested. In the second part, a life cycle assessment for the coproduction of biodiesel and triacetin is made regarding energy and GHG emissions. The system boundaries are set around the production reaction(s) and the production and recovery of the reactant. Data about energy needs and GHG emissions of the processes are extracted from the EcoInvent database. Four scenarios are compared with each other: the biodiesel production from algal oil (BD), and three triacetin coproduction routes: the catalytic interesterification reaction of algal oil with methyl acetate (IRc), the enzymatic interesterification reaction (IRe) and the biodiesel production followed by the esterification of glycerol with acetic acid (ER). The BD scenario scores best in terms of energy and GHG emissions compared to the coproduction scenarios. The main reason is the production of the needed reactants. The production of the reactant used in the coproduction routes consumes more energy and emits more GHG than the production of methanol. Nevertheless, the energy needed for production is less than the energy content of the fuel formed. For the IRe and IR scenarios Enery Return of Investment (EROI) greater than unity is found. Also no… Advisors/Committee Members: UCL - SST/IMMC/TFL - Thermodynamics and fluid mechanics, UCL - Ecole Polytechnique de Louvain, Contino, Francesco, Jeanmart, Hervé, Dias, Véronique, Hubin, Annick, Dayma, Guillaume, Atakan, Burak.

Subjects/Keywords: Biofuels; Chemical kinetics; Life cycle assessment; Pentanoate esters; Triacetin; Laminar flat flames

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Van Damme, S. (2018). Advanced biofuels : oxidation kinetics of methyl pentanoate and life cycle assessment of triacetin. (Thesis). Université Catholique de Louvain. Retrieved from http://hdl.handle.net/2078.1/198378

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Van Damme, Stefanie. “Advanced biofuels : oxidation kinetics of methyl pentanoate and life cycle assessment of triacetin.” 2018. Thesis, Université Catholique de Louvain. Accessed April 12, 2021. http://hdl.handle.net/2078.1/198378.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Van Damme, Stefanie. “Advanced biofuels : oxidation kinetics of methyl pentanoate and life cycle assessment of triacetin.” 2018. Web. 12 Apr 2021.

Vancouver:

Van Damme S. Advanced biofuels : oxidation kinetics of methyl pentanoate and life cycle assessment of triacetin. [Internet] [Thesis]. Université Catholique de Louvain; 2018. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2078.1/198378.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Van Damme S. Advanced biofuels : oxidation kinetics of methyl pentanoate and life cycle assessment of triacetin. [Thesis]. Université Catholique de Louvain; 2018. Available from: http://hdl.handle.net/2078.1/198378

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

11. Bodor, Agnes Livia. Numerical modelling of soot formation and evolution in laminar flames with detailed kinetics : Modélisation numérique de la formation et de l'évolution de la suie dans les flammes laminaires avec cinétique détaillée.

Degree: Docteur es, Combustion, 2019, Université Paris-Saclay (ComUE); Politecnico di Milano

URL: http://www.theses.fr/2019SACLC050

► Les suies de combustion sont principalement connues pour leur caractère nocif, dans le cas des feux de forêt, de fumées de cheminées ou d'émissions polluantes… (more)

▼ Les suies de combustion sont principalement connues pour leur caractère nocif, dans le cas des feux de forêt, de fumées de cheminées ou d'émissions polluantes d'un tuyau d'échappement. Cependant, le noir de carbone, un produit industriel de combustion d'hydrocarbures largement utilisé dans notre vie quotidienne. La surface d'une particule de suies ou de noir de carbon joue un rôle important tant au niveau de son utilisation que de son effet nocif. Il est donc important de connaître la masse, le volume ainsi que la morphologie des suies. En particulier, la surface des particules est un paramètre important pour prédire leur utilisation ainsi que leur effet nocif. Les suies sont généralement des agrégats présentant une structure fractale constituée d'éléments de forme sphérique, appelés particules primaires. Il est possible de connaître la surface des agrégats à partir de la distribution en taille de particules primaires (PPSD-Primary particules size distribution). Compte tenu de l'intérêt grandissant pour la surface des particules et leurs évolutions, il est aujourd’hui nécessaire d'étendre les modèles numériques pour la prévision de la PPSD. De plus, comme la taille des la particules primaires influence les processus chimiques et les processus de collision, la prise en compte de ce paramètre peut améliorer les prévisions des modèles. Les flammes multidimensionnelles laminaires, comme les flammes de diffusion, sont moins complexes que les flammes rencontrées dans les systèmes de combustion industriels. Cependant, les processus de formation de suies sont analogues dans les deux cas, ce qui rend l'étude de ces flammes intéressante. Afin d'obtenir une description détaillée des processus chimiques ayant lieu dans ces flammes tout en maintenant le coût de calcul à un niveau abordable, l'utilisation de modèles sectionnels discrets chimiques (CDSchemical discret sectional methods) est un choix approprié. Le développement de modèles CDS est au coeur de cette thèse. D'abord, une stratégie numérique pour déterminer la taille des particules primaires est présentée dans le contexte des modéles CDS. Elle repose sur la résolution d'une équation de transport pour la densité en nombre de particules primaires pour chaque section d'agrégats considérée. Pour valider la taille des particules primaires déterminée numériquement, les résultats doivent être comparés avec des données expérimentales obtenues via la technique d'Incandescence Induite par Laser résolue temporellement (TiRe-LII). Cette comparaison, dite inverse, est affectée par les incertitudes expérimentales et les hypothèses sous-jacentes au post-traitement du signal TiRe-LII pour obtenir la PSD. Pour améliorer la stratégie de validation, une nouvelle approche, dite directe, est proposée pour la validation de la PPSD à partir des données obtenues par TiRe-LII. Elle est basée sur la reconstruction numérique de l'évolution temporelle du signal d'incandescence à partir des résultats numériques et de sa comparaison avec le signal mesuré. L'efficacité de l'approche proposée est… Advisors/Committee Members: Darabiha, Nasser (thesis director), Cuoci, Alberto (thesis director).

Subjects/Keywords: Suie; Flammes laminaires; Cinétique détaillée; Particules primaires; Soot; Laminar flames; Detailed kinetics; Primary particles

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bodor, A. L. (2019). Numerical modelling of soot formation and evolution in laminar flames with detailed kinetics : Modélisation numérique de la formation et de l'évolution de la suie dans les flammes laminaires avec cinétique détaillée. (Doctoral Dissertation). Université Paris-Saclay (ComUE); Politecnico di Milano. Retrieved from http://www.theses.fr/2019SACLC050

Chicago Manual of Style (16^th Edition):

Bodor, Agnes Livia. “Numerical modelling of soot formation and evolution in laminar flames with detailed kinetics : Modélisation numérique de la formation et de l'évolution de la suie dans les flammes laminaires avec cinétique détaillée.” 2019. Doctoral Dissertation, Université Paris-Saclay (ComUE); Politecnico di Milano. Accessed April 12, 2021. http://www.theses.fr/2019SACLC050.

MLA Handbook (7^th Edition):

Bodor, Agnes Livia. “Numerical modelling of soot formation and evolution in laminar flames with detailed kinetics : Modélisation numérique de la formation et de l'évolution de la suie dans les flammes laminaires avec cinétique détaillée.” 2019. Web. 12 Apr 2021.

Vancouver:

Bodor AL. Numerical modelling of soot formation and evolution in laminar flames with detailed kinetics : Modélisation numérique de la formation et de l'évolution de la suie dans les flammes laminaires avec cinétique détaillée. [Internet] [Doctoral dissertation]. Université Paris-Saclay (ComUE); Politecnico di Milano; 2019. [cited 2021 Apr 12]. Available from: http://www.theses.fr/2019SACLC050.

Council of Science Editors:

Bodor AL. Numerical modelling of soot formation and evolution in laminar flames with detailed kinetics : Modélisation numérique de la formation et de l'évolution de la suie dans les flammes laminaires avec cinétique détaillée. [Doctoral Dissertation]. Université Paris-Saclay (ComUE); Politecnico di Milano; 2019. Available from: http://www.theses.fr/2019SACLC050

King Abdullah University of Science and Technology

12. Alquaity, Awad. Sensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flames.

Degree: Physical Science and Engineering (PSE) Division, 2016, King Abdullah University of Science and Technology

URL: http://hdl.handle.net/10754/621822

► With global emission regulations becoming stringent, development of new combustion technologies that meet future emission regulations is essential. In this vein, this dissertation presents the… (more)

▼ With global emission regulations becoming stringent, development of new combustion technologies that meet future emission regulations is essential. In this vein, this dissertation presents the application of sensitive diagnostic tools to validate and improve chemical kinetic mechanisms that play a fundamental role in the design of new combustion technologies. First, a novel high sensitivity laser-based sensor with a wide frequency tuning range (900 – 1000 cm-1) was developed utilizing pulsed cavity ringdown spectroscopy (CRDS) technique. The novel laser-based sensor was illustrated by measuring trace amounts of multiple combustion intermediates, namely ethylene, propene, allene, and 1-butene in a static cell at ambient conditions. Subsequently, pulsed CRDS technique was utilized to develop an ultra-fast, high sensitivity diagnostic to monitor trace concentrations of ethylene in shock tube pyrolysis experiments. This diagnostic represented the first ever successful application of CRDS technique to transient species measurements in a shock tube. The high sensitivity and fast time response (10μs) diagnostic may be utilized for measuring other key neutrals and radicals which are crucial in the oxidation chemistry of practical fuels. Secondly, a quadrupole mass spectrometer (QMS) was employed to measure relative cation mole fractions in atmospheric and low-pressure (30 Torr) flames of methane/oxygen diluted in argon. Lean, stoichiometric and rich flames were 4 examined to evaluate the dependence of ion chemistry on flame stoichiometry. Spatial distribution of cations was compared with predictions of an existing ion chemistry model. Based on the extensive measurements carried out in this work, modifications were suggested to improve the ion chemistry model to enhance the fidelity of such mechanisms. In-depth understanding of flame ion chemistry is vital to model the interaction of flames with electric fields and thereby pave the way to enable active combustion control for increased efficiency and reduced emissions. Finally, a compact fast time-response time-of-flight mass spectrometer (TOFMS) was coupled to the shock tube through a pin-hole end-wall to enable timeresolved species concentration measurements. This diagnostic tool was demonstrated by investigating the decomposition of 1,3,5-trioxane over a wide range of shock conditions. Reaction rate coefficients were extracted by the best fit to the experimentally measured species time-histories. TOF-MS coupled to the shock tube is an ideal diagnostic tool for developing kinetic mechanisms for future fuels due to its ability to simultaneously measure several species during fuel pyrolysis/oxidation processes. Advisors/Committee Members: Farooq, Aamir (advisor), Dibble, Robert W. (committee member), Sarathy, Mani (committee member), Chung, Suk Ho (committee member), Rieker, Gregory (committee member).

Subjects/Keywords: Mid-IR Sensitive Laser Sensor; Combustion Diagnostics; Shock Tube; Ion Chemistry; Mass Spectrometer; Laminar Flames

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Alquaity, A. (2016). Sensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flames. (Thesis). King Abdullah University of Science and Technology. Retrieved from http://hdl.handle.net/10754/621822

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Alquaity, Awad. “Sensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flames.” 2016. Thesis, King Abdullah University of Science and Technology. Accessed April 12, 2021. http://hdl.handle.net/10754/621822.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Alquaity, Awad. “Sensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flames.” 2016. Web. 12 Apr 2021.

Vancouver:

Alquaity A. Sensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flames. [Internet] [Thesis]. King Abdullah University of Science and Technology; 2016. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10754/621822.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Alquaity A. Sensitive Mid-IR Laser Sensor Development and Mass Spectrometric Measurements in Shock Tube and Flames. [Thesis]. King Abdullah University of Science and Technology; 2016. Available from: http://hdl.handle.net/10754/621822

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

13. Nicoloso, Pedro Ferreira. Avaliação experimental da radiação térmica e geometria de múltiplas chamas não pré-misturadas de gás natural diluído com dióxido de carbono.

Degree: 2019, Brazil

URL: http://hdl.handle.net/10183/196159

►

Combustão em plataformas offshore podem diminuir os gases poluentes lançados ao ambiente, mas ao mesmo tempo afetar negativamente as áreas de trabalho devido as condições… (more)

▼

Combustão em plataformas offshore podem diminuir os gases poluentes lançados ao ambiente, mas ao mesmo tempo afetar negativamente as áreas de trabalho devido as condições de segurança na plataforma impostas durante a queima de gás natural. Por essa razão, um estudo experimental foi conduzido com bancada em escala laboratorial de múltiplas chamas laminares não pré-misturadas. O trabalho consiste de dois queimadores posicionados lado a lado com o intuito de avaliar a geometria da chama e radiação térmica através da variação da distância de separação entre os queimadores. Analisa-se os impactos na geometria de chama e a radiação térmica emitida pelas chamas impondo diferentes concentrações de combustível e diluente durante a combustão. Medições experimentais indicam que as chamas passam por quatro regimes morfológicos em devido a distância de separação: regime imerso sinuoso e imerso varicoso, regime simétrico sinuoso, regime alternado sinuoso e regime independente. O comprimento visível de chama é máximo quando as chamas estão imersas uma na outra no regime imerso sinuoso, distância de separação mínima, e este diminui gradualmente até se obter o valor de jato único na razão S/d igual a 10. Além disso, no regime alternado sinuoso o comprimento de chama torna-se menor que o comprimento de jato único devido a formação de vórtices na base das chamas. A diluição do combustível com CO2 mostrou que as chamas reduzem seu comprimento para quantidades crescentes de CO2 na mistura. Outro efeito da diluição é o de reduzir as oscilações das chamas e a razão S/d para jato único. Equações algébricas foram utilizadas para prever interação de múltiplas chamas e apresentam boa concordância quando se leva em consideração a vazão da mistura. A radiação térmica proveniente de duas chamas em interação tem seu máximo valor em regiões próximas a razão S/d de jato único. A diluição do combustível com CO2 reduz a intensidade de radiação emitida e incremento da vazão de combustível fazem com que a potência de chama aumente que, consequentemente, reduz a fração radiante das chamas. O modelo WMPS apresenta boa concordância para prever o fluxo de calor radiante de duas chamas.

Combustion in offshore platforms can diminish the gaseous polluents released to the atmosphere, but at the same time affect negatively working areas due to safety requirements during the combustion of natural gas. For this reason, an experimental study in lab-scale is taking in consideration to understand the interaction of diffusion flames. This work consist of two circular burners placed side-by-side to evaluate flame geometry and thermal radiation by varying the distance between the two burners. In addition, the impacts on flame geometry and thermal radiation is also evaluated by varying fuel flowrate and diluent on the mixture during combustion. Experiments shows that the flames will be in four different morphological regimes due to spacing: merged sinuous and varicose, symmetric sinuous, alternated sinuous and independent. Flame height is maximum when the flames are…

Advisors/Committee Members: Centeno, Felipe Roman, Pereira, Fernando Marcelo.

Subjects/Keywords: Chamas laminares; Combustão; Gás natural; Radiação térmica; Multiple flames; Natural gas combustion; Diluted fuel; Laminar non-premixed flames; Flames length; Thermal radiation

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Nicoloso, P. F. (2019). Avaliação experimental da radiação térmica e geometria de múltiplas chamas não pré-misturadas de gás natural diluído com dióxido de carbono. (Masters Thesis). Brazil. Retrieved from http://hdl.handle.net/10183/196159

Chicago Manual of Style (16^th Edition):

Nicoloso, Pedro Ferreira. “Avaliação experimental da radiação térmica e geometria de múltiplas chamas não pré-misturadas de gás natural diluído com dióxido de carbono.” 2019. Masters Thesis, Brazil. Accessed April 12, 2021. http://hdl.handle.net/10183/196159.

MLA Handbook (7^th Edition):

Nicoloso, Pedro Ferreira. “Avaliação experimental da radiação térmica e geometria de múltiplas chamas não pré-misturadas de gás natural diluído com dióxido de carbono.” 2019. Web. 12 Apr 2021.

Vancouver:

Nicoloso PF. Avaliação experimental da radiação térmica e geometria de múltiplas chamas não pré-misturadas de gás natural diluído com dióxido de carbono. [Internet] [Masters thesis]. Brazil; 2019. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10183/196159.

Council of Science Editors:

Nicoloso PF. Avaliação experimental da radiação térmica e geometria de múltiplas chamas não pré-misturadas de gás natural diluído com dióxido de carbono. [Masters Thesis]. Brazil; 2019. Available from: http://hdl.handle.net/10183/196159

14. Maron Sauer, Vinicius. Analysis of Laminar Nonpremixed Stagnation Flow and Swirl-Type Tubular Flames.

Degree: Mechanical and Aerospace Engineering, 2017, University of California – Irvine

URL: http://www.escholarship.org/uc/item/48h0j39b

► Combustion is expected to remain one of the main sources of power in the world. Therefore, the understanding of the underlying physical and chemical processes… (more)

Subjects/Keywords: Energy; Coflow Flames; Counterflow Flames; Laminar Flames; Nonpremixed Flames; Tubular Flames

…Nonpremixed Laminar Flames with Simplified Chemistry,” Work-in-Progress Poster, 36th International… …Analysis of Laminar Nonpremixed Stagnation Flow and Swirl-Type Tubular Flames By Vinicius Maron… …laminar flame, in which fuel and oxidizer are initially separated. In nonpremixed flames the… …described. The laminar systems discussed herein are categorized into stagnation flow flames and… …the fundamentals of the theoretical models used to describe laminar nonpremixed flames…

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Maron Sauer, V. (2017). Analysis of Laminar Nonpremixed Stagnation Flow and Swirl-Type Tubular Flames. (Thesis). University of California – Irvine. Retrieved from http://www.escholarship.org/uc/item/48h0j39b

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Maron Sauer, Vinicius. “Analysis of Laminar Nonpremixed Stagnation Flow and Swirl-Type Tubular Flames.” 2017. Thesis, University of California – Irvine. Accessed April 12, 2021. http://www.escholarship.org/uc/item/48h0j39b.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Maron Sauer, Vinicius. “Analysis of Laminar Nonpremixed Stagnation Flow and Swirl-Type Tubular Flames.” 2017. Web. 12 Apr 2021.

Vancouver:

Maron Sauer V. Analysis of Laminar Nonpremixed Stagnation Flow and Swirl-Type Tubular Flames. [Internet] [Thesis]. University of California – Irvine; 2017. [cited 2021 Apr 12]. Available from: http://www.escholarship.org/uc/item/48h0j39b.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Maron Sauer V. Analysis of Laminar Nonpremixed Stagnation Flow and Swirl-Type Tubular Flames. [Thesis]. University of California – Irvine; 2017. Available from: http://www.escholarship.org/uc/item/48h0j39b

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Michigan

15. Yoo, Chunsang. Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects.

Degree: PhD, Mechanical engineering, 2005, University of Michigan

URL: http://hdl.handle.net/2027.42/125553

► For direct numerical simulations of compressible reacting flows, a generalized formulation of the characteristic boundary conditions is proposed. The improved approach resolves several issues of… (more)

▼ For direct numerical simulations of compressible reacting flows, a generalized formulation of the characteristic boundary conditions is proposed. The improved approach resolves several issues of spurious solution behavior encountered in compressible flow simulations. This is accomplished by accounting for all the relevant terms in the determination of the characteristic wave amplitudes and by accommodating a relaxation treatment for the transverse terms with a coefficient determined by the low Mach number asymptotic expansion. The improved boundary conditions are applied to a comprehensive set of test problems and are demonstrated to perform consistently superior to existing approaches. Dynamics of edge flames encountered upon local quenching of nonpremixed flames is studied considering detailed chemistry of hydrogen-air combustion. The density-weighted displacement speed and scalar dissipation rate are found to be appropriate parameters in characterizing the edge flame speed. It is also found that the edge flame speed depends strongly on the transient and history effects of the flow field in addition to the local scalar dissipation rate. Negative edge speed is observed during the early phase of the interaction due to the transverse enthalpy loss induced by large strain. The effects of fuel Lewis number on the edge speed are found to be consistent with the previous theoretical predictions. The dynamics of soot formation in ethylene-air nonpremixed counterflow flames is studies using a semi-empirical soot model and a radiation model based on the discrete ordinate method. Transient characteristics of soot behavior are studied in both laminar and turbulent counterflow configurations. The detailed analysis reveals that the soot number density depends predominantly on flame temperature, while the soot volume fraction is more sensitive to the surface growth mechanism such that it depends on the combined effects of the local conditions of flow, temperature and fuel concentration. The results suggest that accurate prediction of soot volume fraction in turbulent combustion requires consideration of transient and history effects on the evolution of each soot particle. Advisors/Committee Members: Im, Hong G. (advisor).

Subjects/Keywords: Aspects; Computational; Direct; Laminar; Nonpremixed Flames; Numerical; Physical; Simulations; Strained; Turbulent Flames

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Yoo, C. (2005). Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/125553

Chicago Manual of Style (16^th Edition):

Yoo, Chunsang. “Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects.” 2005. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/125553.

MLA Handbook (7^th Edition):

Yoo, Chunsang. “Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects.” 2005. Web. 12 Apr 2021.

Vancouver:

Yoo C. Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects. [Internet] [Doctoral dissertation]. University of Michigan; 2005. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/125553.

Council of Science Editors:

Yoo C. Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects. [Doctoral Dissertation]. University of Michigan; 2005. Available from: http://hdl.handle.net/2027.42/125553

Virginia Tech

16. Khanna, Vivek K. A Study of the Dynamics of Laminar and Turbulent Fully and Partially Premixed Flames.

Degree: PhD, Mechanical Engineering, 2001, Virginia Tech

URL: http://hdl.handle.net/10919/28527

► This present research effort was directed towards developing reduced order models for the dynamics of laminar flat flames, swirl stabilized turbulent flames, and in evaluating… (more)

▼ This present research effort was directed towards developing reduced order models for the dynamics of laminar flat flames, swirl stabilized turbulent flames, and in evaluating the effects of the variation in fuel composition on flame dynamics. The laminar flat flame study was conducted on instrument grade methane, propane, and ethane flames for four total flow rates from 145 cc/sec to 200 cc/sec, and five equivalence ratios from 0.5 to 0.75. The analysis was done by measuring the frequency resolved velocity perturbations, u', and the OH* chemiluminescence, as a measure of unsteady heat release rate, q'. The experimental data showed the corresponding flame dynamics to be fourth order in nature with a pure time delay. One of the resonance was shown to represent the pulsation of the flame location caused by fluctuation in the flame speed and fluctuating heat losses to the flame stabilizer. The other resonance was correlated to the dynamics of the chemical kinetics involved in the combustion process. The time delay was correlated to the chemical time delay. Upon comparing the results of the experiments with the three fuels, it was concluded that for all equivalence ratios studied, propane flame had a higher dynamic gain than methane flames. Ethane flames exhibited a higher dynamic gain than methane flame in the frequency range of 20-100 Hz. Thus, burning of propane instead of methane increased the likelihood of the occurrence of thermo-acoustic instabilities. The experimental techniques developed during the dynamic studies conducted on laminar flat flames were applied to swirl stabilized turbulent flames. Experiments were performed for QAir = 15 scfm and 20 scfm, F = 0.55, 0.6, 0.65, and S = 0.79 and 1.19. The results of fully premixed experiments showed that the flame behaved as a 8th order low pass filter. The results of the partially premixed experiment exhibited a rich spectra, which maintained its bandwidth over the entire range of frequency studied. Comparison of fully and partially premixed flames in the frequency range of 200-400 Hz, indicated that at overall lean conditions the dynamic gain of the totally premixed flames was almost an order of magnitude lower than that of the partially premixed conditions. Thus, it was concluded that combustors with fully premixed flames have a higher probability of being thermo-acoustically stable than those with partially premixed flames. Advisors/Committee Members: Vandsburger, Uri (committeechair), Baumann, William T. (committee member), Saunders, William R. (committee member), Lovett, Jeffery A. (committee member), Richards, George (committee member).

Subjects/Keywords: dynamics; combustion; thermo-acoustic instability; turbulent flames; flame transfer function; laminar flames

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Khanna, V. K. (2001). A Study of the Dynamics of Laminar and Turbulent Fully and Partially Premixed Flames. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/28527

Chicago Manual of Style (16^th Edition):

Khanna, Vivek K. “A Study of the Dynamics of Laminar and Turbulent Fully and Partially Premixed Flames.” 2001. Doctoral Dissertation, Virginia Tech. Accessed April 12, 2021. http://hdl.handle.net/10919/28527.

MLA Handbook (7^th Edition):

Khanna, Vivek K. “A Study of the Dynamics of Laminar and Turbulent Fully and Partially Premixed Flames.” 2001. Web. 12 Apr 2021.

Vancouver:

Khanna VK. A Study of the Dynamics of Laminar and Turbulent Fully and Partially Premixed Flames. [Internet] [Doctoral dissertation]. Virginia Tech; 2001. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10919/28527.

Council of Science Editors:

Khanna VK. A Study of the Dynamics of Laminar and Turbulent Fully and Partially Premixed Flames. [Doctoral Dissertation]. Virginia Tech; 2001. Available from: http://hdl.handle.net/10919/28527

17. Smith, Colin Healey. Studies of rich and ultra-rich combustion for syngas production.

Degree: PhD, Mechanical Engineering, 2012, University of Texas – Austin

URL: http://hdl.handle.net/2152/19578

► Syngas is a mixture of hydrogen (H2), carbon monoxide (CO) and other species including nitrogen (N2), water (H2O), methane (CH4) and higher hydrocarbons. Syngas is… (more)

▼ Syngas is a mixture of hydrogen (H2), carbon monoxide (CO) and other species including nitrogen (N2), water (H2O), methane (CH4) and higher hydrocarbons. Syngas is a highly desired product because it is very versatile. It can be used for combustion in turbines or engines, converted to H2 for use in fuel cells, turned into diesel or other high-molecular weight fuels by the Fischer-Tropsch process and used as a chemical feedstock. Syngas can be derived from hydrocarbons in the presence of oxidizer or water as in steam reforming. There are many demonstrated methods to produce syngas with or without water addition including catalytic methods, plasma reforming and combustion. The goal of this study is to add to the understanding of non-catalytic conversion of hydrocarbon fuels to syngas, and this was accomplished through two investigations: the first on fuel conversion potential and the second on the effect of preheat temperature. A primarily experimental investigation of the conversion of jet fuel and butanol to syngas was undertaken to understand the potential of these fuels for conversion. With these new data and previously-published experimental data, a comparison amongst a larger set of fuels for conversion was also conducted. Significant soot formation was observed in experiments with both fuels, but soot formation was so significant in the jet fuel experiments that it limited the range of experimental operating conditions. The comparison amongst fuels indicated that higher conversion rates are observed with smaller molecular weight fuels, generally. However, equilibrium calculations, which are often used to determine trends in fuel conversion, showed the opposite trend. In order to investigate preheat temperature, which is one important aspect of non-catalytic conversion, experiments were undertaken with burner-stabilized flames that are effectively 1-D and steady-state. An extensive set of model calculations were compared to the obtained experimental data and was used to investigate the effect of preheat temperatures that were beyond what was achievable experimentally. Throughout the range of operating conditions that were tested experimentally, the computational model was excellent in its predictions. Experiments where the reactants were preheated showed a significant expansion of the stable operating range of the burner (increasing the equivalence ratio at which the flame blew off). However, increasing preheat temperature beyond what is required for stabilization did not improve syngas yields. Advisors/Committee Members: Ellzey, Janet L. (advisor), Ezekoye, Ofodike A (committee member), Hidrovo, Carlos H (committee member), Berberoglu, Halil (committee member), Raja, Laxminarayan L (committee member).

Subjects/Keywords: Combustion; Syngas; Jet fuel; Butanol; Laminar flames; Preheated flames

…about 200 K, but the laminar flame speed increases by almost 4 times. Flames propagate through… …with burner-stabilized flames that are effectively 1-D and steady-state. An extensive set of… …FLAMES .....................................................................82 3.1 Analytical… …Effect of Preheat on BurnerStabilized Flames… …because the propagation of a flame requires heat and mass transfer. The laminar flame speed of a…

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Smith, C. H. (2012). Studies of rich and ultra-rich combustion for syngas production. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/19578

Chicago Manual of Style (16^th Edition):

Smith, Colin Healey. “Studies of rich and ultra-rich combustion for syngas production.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed April 12, 2021. http://hdl.handle.net/2152/19578.

MLA Handbook (7^th Edition):

Smith, Colin Healey. “Studies of rich and ultra-rich combustion for syngas production.” 2012. Web. 12 Apr 2021.

Vancouver:

Smith CH. Studies of rich and ultra-rich combustion for syngas production. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2152/19578.

Council of Science Editors:

Smith CH. Studies of rich and ultra-rich combustion for syngas production. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/19578

18. Demarco, Rodrigo. Modelling thermal radiation and soot formation in buoyant diffision flames : Modélisation du rayonnement thermique et de la formation de suies dans des flammes de diffusion affectes par des forces de flottabilité.

Degree: Docteur es, Energétique, 2012, Aix Marseille Université

URL: http://www.theses.fr/2012AIXM4745

►

Le rayonnement joue un rôle fondamental dans les problèmes d'incendie puisque c'est le mode dominant de transfert de chaleur entre la flamme et le milieu… (more)

▼

Le rayonnement joue un rôle fondamental dans les problèmes d'incendie puisque c'est le mode dominant de transfert de chaleur entre la flamme et le milieu environnant. Il contrôle la pyrolyse, et donc la puissance de flamme, et la vitesse de croissance de l'incendie. Étudier les flammes de diffusion contrôlées par les forces de flottabilité est une première étape pour comprendre et de prédire les incendies. Le principal objectif de ce travail est de modéliser le transfert radiatif et les processus de production/destruction de la suie dans ce type de flammes. Premièrement, différents modèles de propriétés radiatives des gaz ont été comparés dans des configurations tests. Il est apparu que le modèle FSCK couplé avec le schéma de mélange de Modest et Riazzi est le meilleur compromis entre précision et temps de calcul, ce modèle étant un bon candidat pour être implémenté dans des codes CFD traitant des problèmes d'incendie. Dans un second temps, un modèle de formation/oxydation des suies semi-détaillé, considérant l'acétylène et le benzène comme précurseurs, a été validé dans des flammes de diffusion laminaires de type coflow sur une large gamme d'hydrocarbures (C1-C3) et pour différentes conditions. Ensuite, le FSCK et le modèle de formation/destruction ont été appliqués pour simuler des feux de nappe de méthane et de propane aux échelles du laboratoire et intermédiaire. Les structures de flamme prédites ainsi que les flux radiatif transférés au milieu environnant ont montré un bon accord avec les résultats expérimentaux disponibles. Finalement, les interactions entre le rayonnement et la turbulence ont été quantifiées.

The radiative heat transfer plays an important role in fire problems since it is the dominant mode of heat transfer between flames and surroundings. It controls the pyrolysis, and therefore the heat release rate, and the growth rate of the fire. In the present work a numerical study of buoyant diffusion flames is carried out, with the main objective of modelling the thermal radiative transfer and the soot formation/destruction processes. In a first step, different radiative property models were tested in benchmark configurations. It was found that the FSCK coupled with the Modest and Riazzi mixing scheme was the best compromise in terms of accuracy and computational requirements, and was a good candidate to be implemented in CFD codes dealing with fire problems. In a second step, a semi-empirical soot model, considering acetylene and benzene as precursor species for soot nucleation, was validated in laminar coflow diffusion flames over a wide range of hydrocarbons (C1-C3) and conditions. In addition, the optically-thin approximation was found to produce large discrepancies in the upper part of these small laminar flames. Reliable predictions of soot volume fractions require the use of an advanced radiation model. Then the FSCK and the semi-empirical soot model were applied to simulate laboratory-scale and intermediate-scale pool fires of methane and propane. Predicted flame structures as well as the…

Advisors/Committee Members: Consalvi, Jean-Louis (thesis director).

Subjects/Keywords: Rayonnement thermique; Modèle de suies; Flamme laminaire de diffusion; Flamme turbulente de diffusion; Thermal radiation; Soot model; Laminar diffusion flames; Turbulent diffusion flames

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Demarco, R. (2012). Modelling thermal radiation and soot formation in buoyant diffision flames : Modélisation du rayonnement thermique et de la formation de suies dans des flammes de diffusion affectes par des forces de flottabilité. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2012AIXM4745

Chicago Manual of Style (16^th Edition):

Demarco, Rodrigo. “Modelling thermal radiation and soot formation in buoyant diffision flames : Modélisation du rayonnement thermique et de la formation de suies dans des flammes de diffusion affectes par des forces de flottabilité.” 2012. Doctoral Dissertation, Aix Marseille Université. Accessed April 12, 2021. http://www.theses.fr/2012AIXM4745.

MLA Handbook (7^th Edition):

Demarco, Rodrigo. “Modelling thermal radiation and soot formation in buoyant diffision flames : Modélisation du rayonnement thermique et de la formation de suies dans des flammes de diffusion affectes par des forces de flottabilité.” 2012. Web. 12 Apr 2021.

Vancouver:

Demarco R. Modelling thermal radiation and soot formation in buoyant diffision flames : Modélisation du rayonnement thermique et de la formation de suies dans des flammes de diffusion affectes par des forces de flottabilité. [Internet] [Doctoral dissertation]. Aix Marseille Université 2012. [cited 2021 Apr 12]. Available from: http://www.theses.fr/2012AIXM4745.

Council of Science Editors:

Demarco R. Modelling thermal radiation and soot formation in buoyant diffision flames : Modélisation du rayonnement thermique et de la formation de suies dans des flammes de diffusion affectes par des forces de flottabilité. [Doctoral Dissertation]. Aix Marseille Université 2012. Available from: http://www.theses.fr/2012AIXM4745

19. Rakha, Ihsan Allah. Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures.

Degree: Physical Science and Engineering (PSE) Division, 2015, King Abdullah University of Science and Technology

URL: http://hdl.handle.net/10754/554400

► The steady coflow diffusion flame is a widely used configuration for studying combustion kinetics, flame dynamics, and pollutant formation. In the current work, a set… (more)

Subjects/Keywords: Soot Formation; Laminar Coflow Flames; Ethylene-Air Flames; Combustion

…processes. Due to their simplicity, two-dimensional axisymmetric laminar diffusion flames are… …the early numerical studies of soot formation in laminar co-flow diffusion flames at… …Liu et al. [7] reported the same findings for laminar methane-air flames at 1 atm… …formation in laminar diffusion flames at elevated pressures. Zhang and Ezekoye [8]… …air and ethylene/air laminar diffusion co-flow flames. Their model over-predicted the value…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Rakha, I. A. (2015). Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures. (Thesis). King Abdullah University of Science and Technology. Retrieved from http://hdl.handle.net/10754/554400

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Rakha, Ihsan Allah. “Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures.” 2015. Thesis, King Abdullah University of Science and Technology. Accessed April 12, 2021. http://hdl.handle.net/10754/554400.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Rakha, Ihsan Allah. “Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures.” 2015. Web. 12 Apr 2021.

Vancouver:

Rakha IA. Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures. [Internet] [Thesis]. King Abdullah University of Science and Technology; 2015. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/10754/554400.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Rakha IA. Numerical Modelling of Soot Formation in Laminar Axisymmetric Ethylene-Air Coflow Flames at Atmospheric and Elevated Pressures. [Thesis]. King Abdullah University of Science and Technology; 2015. Available from: http://hdl.handle.net/10754/554400

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of California – San Diego

20. Moreno Boza, Daniel. Stability and asymptotic analyses of effects of buoyancy on reactive flows.

Degree: Engineering Sciences (Aerospace Engineering), 2017, University of California – San Diego

URL: http://www.escholarship.org/uc/item/9sf7w4rn

► Asymptotic methods and experimental techniques have been used in combination with direct numerical simulations and stability analyses to investigate effects of buoyancy-driven motion in two… (more)

▼ Asymptotic methods and experimental techniques have been used in combination with direct numerical simulations and stability analyses to investigate effects of buoyancy-driven motion in two different reactive problems, namely, flickering of nonpremixed diffusion flames in open atmospheres and slowly reacting combustion of confined mixtures. A brief description of these two separate topics is given below.Part I of this dissertation deals with the flickering of jet diffusion flames and the puffing of liquid-fuel pool fires. Both phenomena are a manifestation of an axisymmmetric global hydrodynamic instability driven by the interactions of the buoyancy force with thedensity differences induced by the chemical heat release, which occurs in the flame sheet separating the fuel and oxidizer domains. For these flows, the predictive capability of local quasi-parallel stability analyses is limited by the non-slender character of the resultingeigenmodes, so that a biglobal analysis is needed to accurately determine marginal instability conditions and resulting frequencies. The results for jet diffusion flames, including the Froude number/Reynolds number instability boundaries for different fuel-feed dilutions,are compared with direct numerical simulations, giving good agreement for the range of conditions explored in our study. For liquid-fuel pool fires, the stability analysis provides the critical value of the Rayleigh number at the onset of the puffing instability. The predictions for different liquid fuels are compared with the results obtained in small-scale laboratory experiments.Part II is concerned with the “slowly reacting” mode of combustion, and its thermal-explosion limits, of an initially cold gaseous mixture enclosed in a spherical vessel with a constant wall temperature, a relevant problem in connection with the safe storageand transportation of reactant gas mixtures. Following Frank-Kamenetskii’s seminal analysis of this problem, the strong temperature dependence of the effective overall reaction rate is taken into account by using a single-reaction model with an Arrhenius rate havinga large activation energy, resulting in a critical value Da_c of the controlling Damköhler number above which the slowly reacting mode of combustion no longer exists. A Rayleigh number Ra based on the relevant density difference is seen to measure the relative effect ofnatural convection. Our numerical computations indicate that the value of Da_c increases with Ra as a result of the enhanced heat-transfer rate. Specific consideration is given to the flow structure in the asymptotic limits Ra << 1 and Ra >> 1, which yield accuratepredictions of critical explosion conditions. For completeness, the application of Frank-Kamenetskii’s ideas to the problem of flow of a reactive mixture in a pipe is presented in an appendix for the case of buoyancy-free conditions.

Subjects/Keywords: Aerospace engineering; Mechanical engineering; Asymptotic analysis; Global stability analysis; Laminar diffusion flames; Reactive flows; Thermal explosion limits

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Moreno Boza, D. (2017). Stability and asymptotic analyses of effects of buoyancy on reactive flows. (Thesis). University of California – San Diego. Retrieved from http://www.escholarship.org/uc/item/9sf7w4rn

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Moreno Boza, Daniel. “Stability and asymptotic analyses of effects of buoyancy on reactive flows.” 2017. Thesis, University of California – San Diego. Accessed April 12, 2021. http://www.escholarship.org/uc/item/9sf7w4rn.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Moreno Boza, Daniel. “Stability and asymptotic analyses of effects of buoyancy on reactive flows.” 2017. Web. 12 Apr 2021.

Vancouver:

Moreno Boza D. Stability and asymptotic analyses of effects of buoyancy on reactive flows. [Internet] [Thesis]. University of California – San Diego; 2017. [cited 2021 Apr 12]. Available from: http://www.escholarship.org/uc/item/9sf7w4rn.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Moreno Boza D. Stability and asymptotic analyses of effects of buoyancy on reactive flows. [Thesis]. University of California – San Diego; 2017. Available from: http://www.escholarship.org/uc/item/9sf7w4rn

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

21. Maugendre, Mathieu. Etude des particules de suie dans les flammes de kérosène et de diester : Study of soots particles in kerosene and biofuel flames.

Degree: Docteur es, Physique, 2009, Rouen, INSA

URL: http://www.theses.fr/2009ISAM0016

►

Les suies se présentent sous la forme de fines particules carbonées de diamètres compris entre quelques dizaines de nanomètres à quelques micromètres. Dans l’atmosphère, elles… (more)

▼

Les suies se présentent sous la forme de fines particules carbonées de diamètres compris entre quelques dizaines de nanomètres à quelques micromètres. Dans l’atmosphère, elles entraînent des enjeux climatiques, de par leurs propriétés radiatives, mais aussi des enjeux sanitaires, du fait de leur faible taille : elles pénètrent facilement dans le système respiratoire et même, pour les plus fines, dans le système sanguin. L’objectif est de parfaire les connaissances sur les propriétés physiques des suies produites par différents systèmes de combustion. C’est dans le but de mieux comprendre l’influence des systèmes de combustion, faisant intervenir des temps de séjours différents, des propriétés de turbulence, d’oxydation et de pression distinctes que nous avons choisi d’étudier trois types de combustion spécifiques : d’une part, des flammes de diffusion laminaires à pression atmosphérique, initiées dans un brûleur développé au cours de ces travaux ; d’autre part, une flamme de diffusion laminaire sous atmosphère pressurisée (3 à 5 bars) ; enfin, une flamme turbulente produite par une chambre tubulaire, elle aussi sous atmosphère pressurisée (1.2 à 3 bar). Un autre enjeu de ce travail était d’approfondir les informations relatives à la combustion de carburants liquides, à savoir le kérosène et le diester. Les travaux effectués visent à déterminer les caractéristiques morphologiques (dimension fractale, diamètre des monomères...) et l’indice complexe m* des suies issues des différents systèmes de combustion. La technique employée pour la mesure de l’indice complexe de réfraction des suies, repose sur l’analyse d’une partie des fumées produites par les flammes. Ces fumées sont acheminées dans un banc d’analyse permettant la mesure de signaux d’extinction et de diffusion, ainsi que de distributions de taille des suies. Par ailleurs, des analyses de clichés obtenus par microscope en transmission d’électrons (TEM) permettent l’obtention d’informations sur la morphologie des agrégats de suies. L’utilisation de la théorie de la diffusion de la lumière pour des agrégats fractals dans la limite de Rayleigh (RDG-FA) permet d’estimer à partir de ces données deux fonctions de l’indice complexe E(m) et F(m), et ainsi de retrouver m*.

Soot are carbonaceous fine particles, which diameters are ranged from a few nanometres to a few micrometers. They have an impact on climate, due to their radiative properties, as well as on health, due to their small size. That’s why particulate matter is an important concern. In order to gain a better understanding of the influence of the combustion devices, which implies specific residence time and also specific turbulence, oxidation and pressure properties, we studied three specific kinds of combustion : first, laminar diffusion flames at atmospheric pressure ; then, a laminar diffusion flame a high pressures (3 to 5 bar) ; finally, a turbulent flame produced in a combustor at high pressures (1,2 to 3 bar). Another objective of this work was to improve the knowledge about soot produced by the…

Advisors/Committee Members: Coppalle, Alexis (thesis director).

Subjects/Keywords: Particules de suie; Flamme de diffusion laminaire; Flamme turbulente; Soot particles; Laminar diffusion flames; Turbulent flame

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Maugendre, M. (2009). Etude des particules de suie dans les flammes de kérosène et de diester : Study of soots particles in kerosene and biofuel flames. (Doctoral Dissertation). Rouen, INSA. Retrieved from http://www.theses.fr/2009ISAM0016

Chicago Manual of Style (16^th Edition):

Maugendre, Mathieu. “Etude des particules de suie dans les flammes de kérosène et de diester : Study of soots particles in kerosene and biofuel flames.” 2009. Doctoral Dissertation, Rouen, INSA. Accessed April 12, 2021. http://www.theses.fr/2009ISAM0016.

MLA Handbook (7^th Edition):

Maugendre, Mathieu. “Etude des particules de suie dans les flammes de kérosène et de diester : Study of soots particles in kerosene and biofuel flames.” 2009. Web. 12 Apr 2021.

Vancouver:

Maugendre M. Etude des particules de suie dans les flammes de kérosène et de diester : Study of soots particles in kerosene and biofuel flames. [Internet] [Doctoral dissertation]. Rouen, INSA; 2009. [cited 2021 Apr 12]. Available from: http://www.theses.fr/2009ISAM0016.

Council of Science Editors:

Maugendre M. Etude des particules de suie dans les flammes de kérosène et de diester : Study of soots particles in kerosene and biofuel flames. [Doctoral Dissertation]. Rouen, INSA; 2009. Available from: http://www.theses.fr/2009ISAM0016

University of Michigan

22. Qiao, Li. Effects of diluents on laminar premixed hydrogen flames in microgravity.

Degree: PhD, Mechanical engineering, 2007, University of Michigan

URL: http://hdl.handle.net/2027.42/126802

► An experimental and computational study of the effects of diluents on the properties of laminar premixed hydrogen flames in microgravity was carried out during the… (more)

▼ An experimental and computational study of the effects of diluents on the properties of laminar premixed hydrogen flames in microgravity was carried out during the present investigation. The microgravity experiments made use of a short-drop free-fall laboratory facility that provided at least 450 ms of 10^-2 g conditions. Outwardly propagating spherical flames were used to measure laminar burning velocities at fuel-equivalence ratios of 1.0 and 1.8, and at pressures of 0.5, 0.7 and 1.0 atm, containing varying concentrations of He, Ar, N₂ and CO₂ as fire suppressants. Burning velocities were also computed using the steady, one-dimensional laminar premixed flame code PREMIX with detailed chemical kinetics, transport properties, and radiative heat loss. Measured and computed results both showed the suppressant effectiveness (based on the reduction of burning velocity for a given concentration) to increase in the order He, Ar, N₂ and CO₂. This is attributed to two different physical effects: quenching of chain reaction due to the lower temperatures produced by the suppressant effects on the specific heats of the gases, and changes in the transport rates in the flame reaction zone. However the suppressants can also decrease the Markstein number, especially for CO₂, causing the flames to become more susceptible to preferential-diffusion instability. The resulting increase in flame surface wrinkling increases the burning velocity, thus counteracting the desired effect of the flame suppressant. Far from the flammability limit, the agreement between measured and computed laminar burning velocities was found to be good. For near-limit flames, however, the computed and measured burning velocities deviated noticeably, with the observed differences being substantially larger than the measured uncertainties. Sensitivity analyses suggest that inaccuracies in three-body termination rates for H+O₂+M=HO₂+M reactions, particularly in the third-body chaperon efficacy of various species M, and in mass diffusion coefficients, particularly for H₂ diffusion, are the most likely explanation for these near-limit differences. Advisors/Committee Members: Dahm, Werner J. A. (advisor), Oran, Elaine S. (advisor).

Subjects/Keywords: Diluents; Effects; Flames; Hydrogen; Laminar; Microgravity; Premixed

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Qiao, L. (2007). Effects of diluents on laminar premixed hydrogen flames in microgravity. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/126802

Chicago Manual of Style (16^th Edition):

Qiao, Li. “Effects of diluents on laminar premixed hydrogen flames in microgravity.” 2007. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/126802.

MLA Handbook (7^th Edition):

Qiao, Li. “Effects of diluents on laminar premixed hydrogen flames in microgravity.” 2007. Web. 12 Apr 2021.

Vancouver:

Qiao L. Effects of diluents on laminar premixed hydrogen flames in microgravity. [Internet] [Doctoral dissertation]. University of Michigan; 2007. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/126802.

Council of Science Editors:

Qiao L. Effects of diluents on laminar premixed hydrogen flames in microgravity. [Doctoral Dissertation]. University of Michigan; 2007. Available from: http://hdl.handle.net/2027.42/126802

University of Michigan

23. Lin, Kuo-Cheng. Hydrodynamic effects on soot formation in laminar hydrocarbon-fueled diffusion flames.

Degree: PhD, Applied Sciences, 1996, University of Michigan

URL: http://hdl.handle.net/2027.42/130047

► An experimental and numerical study of hydrodynamic effects on soot formation in laminar hydrocarbon-fueled diffusion flames was conducted. The main issues addressed were hydrodynamic suppression… (more)

▼ An experimental and numerical study of hydrodynamic effects on soot formation in laminar hydrocarbon-fueled diffusion flames was conducted. The main issues addressed were hydrodynamic suppression of soot formation in laminar diffusion flames, fundamental processes of soot nucleation and growth in laminar coflowing-jet diffusion flames, and the structure of soot-free (permanently-blue) opposed-jet diffusion flames. The existence of state relationships in permanently-blue diffusion flames was also examined. The experiments involved acetylene, propylene and 1,3-butadiene coflowing-jet diffusion flames, burning in air with air/fuel-stream velocity ratios in the range 0.4-6.7 and pressures in the range 0.19-0.50 atm; and hydrocarbon-fueled opposed-jet diffusion flames, burning at atmospheric pressure with stoichiometric mixture fractions in the range 0.06-0.78 and strain rates ranging from 30 s^-1 to flame extinction conditions. Measurements included laminar smoke-point flame lengths, soot volume fractions, soot and gas temperatures, soot structure, gas compositions and flow velocities. Numerical simulations were based on the CHEMKIN algorithm, using the OPPDIF code and both the GRI-mech and Peters' mechanisms, for permanently-blue ethylene opposed-jet diffusion flames with a stoichiometric mixture fraction of 0.7 and strain rates of 60, 120 and 240 s^-1. The measurements showed that laminar smoke-point flame lengths can be increased and soot emissions possibly suppressed entirely, by increasing the air/fuel-stream velocity ratios for coflowing-jet diffusion flames; in addition, the critical strain rates at soot-particle inception can be decreased and soot emissions can also possibly be suppressed entirely, by increasing the stoichiometric mixture fractions for opposed-jet diffusion flames. The mechanism of these effects involves the manipulating direction of the flow velocities relative to the flame sheet and the soot residence times available for soot nucleation and growth. Soot nucleation and growth rates exhibit first-order behavior with respect to acetylene concentrations, with an activation energy of 39 kcal/gmole and a collision efficiency of 0.0030. The structure of permanently-blue ethylene diffusion flames can be predicted quite well using the GRI-mech and Peters' mechanisms; in addition, reasonably universal state relationships for temperature and major gas species are observed for the permanently-blue flames over a wide range of strain rates. Advisors/Committee Members: Faeth, Gerard M. (advisor).

Subjects/Keywords: Diffusion; Effects; Flames; Formation; Fueled; Hydrocarbon; Hydrodynamic; Laminar; Soot

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Lin, K. (1996). Hydrodynamic effects on soot formation in laminar hydrocarbon-fueled diffusion flames. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/130047

Chicago Manual of Style (16^th Edition):

Lin, Kuo-Cheng. “Hydrodynamic effects on soot formation in laminar hydrocarbon-fueled diffusion flames.” 1996. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/130047.

MLA Handbook (7^th Edition):

Lin, Kuo-Cheng. “Hydrodynamic effects on soot formation in laminar hydrocarbon-fueled diffusion flames.” 1996. Web. 12 Apr 2021.

Vancouver:

Lin K. Hydrodynamic effects on soot formation in laminar hydrocarbon-fueled diffusion flames. [Internet] [Doctoral dissertation]. University of Michigan; 1996. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/130047.

Council of Science Editors:

Lin K. Hydrodynamic effects on soot formation in laminar hydrocarbon-fueled diffusion flames. [Doctoral Dissertation]. University of Michigan; 1996. Available from: http://hdl.handle.net/2027.42/130047

University of Michigan

24. Sunderland, Peter Bradford. Soot formation in laminar jet diffusion flames.

Degree: PhD, Mechanical engineering, 1995, University of Michigan

URL: http://hdl.handle.net/2027.42/129570

► The structure and soot properties of round laminar jet hydrocarbon diffusion flames burning in air were studied experimentally. Ten normal-gravity flames were investigated in detail,… (more)

▼ The structure and soot properties of round laminar jet hydrocarbon diffusion flames burning in air were studied experimentally. Ten normal-gravity flames were investigated in detail, including four burning acetylene due to the widely recognized importance of acetylene in soot formation and one each burning ethane, propane, n-butane, ethylene, propylene and 1,3-butadiene. In order to maintain manageable soot concentrations, the ambient pressure was varied from 25-99 kPa and nitrogen dilution was added to some fuels. The measurements emphasized properties along the flame axes, where soot processes most resemble those in nonbuoyant diffusion flames. The measurements included: soot volume fractions, temperatures, soot structure, concentrations of major gas species, and velocities. Along the axes of the present test flames, soot was first observed when temperatures reached 1250 K, and soot formation ended when fuel-equivalence ratios decreased to 1.4. Observations of the four acetylene flames yielded soot growth rates similar to past observations of new soot in premixed flames and, after correction for soot oxidation, revealed first-order growth with respect to acetylene concentrations with a negligible activation energy and an acetylene/soot collision efficiency of 0.41%. Observations of the other hydrocarbon flames revealed higher soot growth rates at corresponding acetylene concentrations, which were attributed to a parallel ethylene growth channel with a collision efficiency of 1.41%. Present measurements of soot nucleation rates indicated first-order nucleation with respect to acetylene concentrations in all the flames with an activation energy of 35 kcal/gmole. In addition to the measurements in flames at normal gravity, laminar smoke points were determined for a number of low-gravity laminar jet diffusion flames using the NASA KC-135 flying laboratory. These involved propane- and ethylene-air flames at pressures of 0.5, 1.0 and 2.0 atm. The laminar smoke point luminosity lengths of these nonbuoyant flames were found to be independent of burner diameter and roughly one fourth as long as the smoke-point lengths of corresponding flames in normal gravity. The latter observation results from different soot paths for the buoyant and nonbuoyant jet diffusion flames. Advisors/Committee Members: Faeth, Gerard M. (advisor).

Subjects/Keywords: Diffusion Flame; Flames; Formation; Jet; Laminar; Soot

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sunderland, P. B. (1995). Soot formation in laminar jet diffusion flames. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/129570

Chicago Manual of Style (16^th Edition):

Sunderland, Peter Bradford. “Soot formation in laminar jet diffusion flames.” 1995. Doctoral Dissertation, University of Michigan. Accessed April 12, 2021. http://hdl.handle.net/2027.42/129570.

MLA Handbook (7^th Edition):

Sunderland, Peter Bradford. “Soot formation in laminar jet diffusion flames.” 1995. Web. 12 Apr 2021.

Vancouver:

Sunderland PB. Soot formation in laminar jet diffusion flames. [Internet] [Doctoral dissertation]. University of Michigan; 1995. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/2027.42/129570.

Council of Science Editors:

Sunderland PB. Soot formation in laminar jet diffusion flames. [Doctoral Dissertation]. University of Michigan; 1995. Available from: http://hdl.handle.net/2027.42/129570

Texas A&M University

25. Siwatch, Vivek. Modeling of NOx formation in circular laminar jet flames.

Degree: MS, Mechanical Engineering, 2007, Texas A&M University

URL: http://hdl.handle.net/1969.1/4749

► Emissions of oxides of nitrogen (NOx) from combustion devices is a topic of tremendous current importance. The bulk of the review of NOx emissions has… (more)

▼ Emissions of oxides of nitrogen (NOx) from combustion devices is a topic of tremendous current importance. The bulk of the review of NOx emissions has been in the field of turbulent jet flames. However laminar jet flames have provided much insight into the relative importance of NOx reaction pathways in non premixed combustion for various flame conditions. The existing models include detailed chemistry kinetics for various species involved in the flame. These detailed models involve very complex integration of hundreds of chemical reactions of various species and their intermediates. Hence such models are highly time consuming and also normally involve heavy computational costs. This work proposes a numerical model to compute the total production of NOx in a non-premixed isolated circular laminar jet flame. The jet consists of the fuel rich inner region and the O2 rich outer region. The model estimates both thermal NOx and prompt NOx assuming single step kinetics for NOx formation and a thin flame model. Further the amount of air entrainment by jet depends upon the Sc number of fuel. The higher the Sc number, the higher is the air entrained which lowers the flame temperature and hence NOx formation. With increasing Sc number, flame volume increases which leads to an increase in the NOx formation. The effect of the Sc number variation on the net production of NOx and flame structure is also investigated. The effect of equilibrium chemistry for CO2 <-> CO + 1/2 O2 and H2O <-> H2 +1/2 O2 on total NOx emission is studied. Also the effect of both CO2 and H2O equilibrium is considered simultaneously and the net x NO formation for propane is 45 ppm. The split between pre-flame and post-flame regions is also investigated. For Propane, 96% of NO emissions occur in the pre-flame region and about 4% in the post-flame region. The model predictions are compared with experimental values of NOx missions reported elsewhere. Advisors/Committee Members: Annamalai, Kalyan (advisor), Girimaji, Sharath (committee member), Han, Je (committee member).

Subjects/Keywords: NOx; Flames; Zeldovich; Prompt; Sc; Laminar; Siwatch

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Siwatch, V. (2007). Modeling of NOx formation in circular laminar jet flames. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/4749

Chicago Manual of Style (16^th Edition):

Siwatch, Vivek. “Modeling of NOx formation in circular laminar jet flames.” 2007. Masters Thesis, Texas A&M University. Accessed April 12, 2021. http://hdl.handle.net/1969.1/4749.

MLA Handbook (7^th Edition):

Siwatch, Vivek. “Modeling of NOx formation in circular laminar jet flames.” 2007. Web. 12 Apr 2021.

Vancouver:

Siwatch V. Modeling of NOx formation in circular laminar jet flames. [Internet] [Masters thesis]. Texas A&M University; 2007. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/1969.1/4749.

Council of Science Editors:

Siwatch V. Modeling of NOx formation in circular laminar jet flames. [Masters Thesis]. Texas A&M University; 2007. Available from: http://hdl.handle.net/1969.1/4749

University of Toronto

26. Wang, Weichao. Experimental and Numerical Investigation of Structure and Extinction Limits of Biofuels in Laminar Counterflow Diffusion Flames.

Degree: 2014, University of Toronto

URL: http://hdl.handle.net/1807/67886

►

Extinction of laminar counterflow diffusion flames were investigated at atmospheric pressures as a function of nitrogen dilution through experiment and two-dimensional axisymmetric full domain numerical… (more)

Subjects/Keywords: Ethanol combustion; Flame extinction; Laminar counterflow diffusion flames; Numerical combustion modelling; Strain rate; Syngas combustion; 0538

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, W. (2014). Experimental and Numerical Investigation of Structure and Extinction Limits of Biofuels in Laminar Counterflow Diffusion Flames. (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/67886

Chicago Manual of Style (16^th Edition):

Wang, Weichao. “Experimental and Numerical Investigation of Structure and Extinction Limits of Biofuels in Laminar Counterflow Diffusion Flames.” 2014. Masters Thesis, University of Toronto. Accessed April 12, 2021. http://hdl.handle.net/1807/67886.

MLA Handbook (7^th Edition):

Wang, Weichao. “Experimental and Numerical Investigation of Structure and Extinction Limits of Biofuels in Laminar Counterflow Diffusion Flames.” 2014. Web. 12 Apr 2021.

Vancouver:

Wang W. Experimental and Numerical Investigation of Structure and Extinction Limits of Biofuels in Laminar Counterflow Diffusion Flames. [Internet] [Masters thesis]. University of Toronto; 2014. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/1807/67886.

Council of Science Editors:

Wang W. Experimental and Numerical Investigation of Structure and Extinction Limits of Biofuels in Laminar Counterflow Diffusion Flames. [Masters Thesis]. University of Toronto; 2014. Available from: http://hdl.handle.net/1807/67886

27. Vallinayagam pillai, Subramanian. Modélisation de la combustion turbulente : application des méthodes de tabulation de la chimie détaillée l'allumage forcé : Numerical simulation of forced ignition using LES coupled with a tabulated detailed chemistry approach.

Degree: Docteur es, Energétique, 2010, Rouen, INSA

URL: http://www.theses.fr/2010ISAM0001

►

L'optimisation des systèmes d'allumage est un paramètre critique pour la définition des foyers de combustion industriels. Des simulations aux grandes échelles (ou LES pour Large-Eddy… (more)

▼

L'optimisation des systèmes d'allumage est un paramètre critique pour la définition des foyers de combustion industriels. Des simulations aux grandes échelles (ou LES pour Large-Eddy Simulation) d'un brûleur de type bluff-body non pré-mélangé ont été menées afin de comprendre l'influence de la position de la bougie sur la probabilité d'allumage. La prise en compte de la combustion est basée sur une méthode de tabulation de la chimie détaillée (PCM-FPI pour Presumed Conditional Moments - Flame Prolongation of ILDM). Les résultats de ces simulations ont été confrontés des résultats expérimentaux disponibles dans la littérature. Dans un premier temps, les mesures de vitesse et du champ de richesse à froid sont comparées aux résultats de la simulation pour évaluer les capacités de prédiction en terme de structure de l'écoulement et de mélange turbulent. Un suivi temporel des vitesses et de la fraction de mélange est réalisé à différents points pour déterminer les fonctions de densité de probabilité (ou PDF)des variables caractéristiques de l'écoulement, à partir des champs résolus en LES. Les PDFs ainsi obtenues servent l'analyse des phénomènes d'allumages réussis ou déficients rencontrés expérimentalement. Des simulations d'allumage forcé ont été effectuées pour analyser les différents scénarios de développement de la flamme. Les corrélations entre les valeurs locales (fraction de mélange, vitesse) autour de la position d'allumage et les chances de succès de développement du noyau de gaz brûlés sont alors discutées. Enfin, une extension de la méthode PCM-FPI avec prise en compte des effets d'étirement est développée à l'aide d'une analyse asymptotique, puis confrontée aux résultats de mesures expérimentales.

The optimization of the ignition process is a crucial issue in the design of many combustion systems. Large eddy simulation (LES) of a conical shaped bluff-body turbulent non-premixed burner has been performed to study the impact of spark location on ignition success. The chemistry part of the simulation is done using tabulated detailed chemistry approach. This burner was experimentally investigated by Ahmed et al at Cambridge (UK). The present work focuses on the case without swirl for which detailed measurements are available. First, cold fkow measurements of velocities and mixture fraction are compared with their LES counterparts, to assess the prediction capabilities of simulations in terms of flow and turbulent mixing. Time history of velocities and mixture fraction are recorded at selected spots, to probe the resolved probability density function (pdf) of flow variables, in an attempt to reproduce, from the knowledge of LES resolved instantaneous flow conditions, the experimentally observed reasons of success or failure of spark ignition. A flammability map is also constructed from the resolved mixture fraction pdf and compared with its experimental counterpart. LES of forced ignition is then performed using flamelet fully detailed tabulated chemistry combined with presumed pdfs (PCM-FPI). Various scenarios…

Advisors/Committee Members: Domingo, Pascale (thesis director), Vervisch, Luc (thesis director).

Subjects/Keywords: Simulation aux grandes échelles; Allumage forcé; Flammelettes laminaires; Flammes turbulentes; Large eddy simulation; Spark ignition; Laminar flamelets; Turbulent flames

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Vallinayagam pillai, S. (2010). Modélisation de la combustion turbulente : application des méthodes de tabulation de la chimie détaillée l'allumage forcé : Numerical simulation of forced ignition using LES coupled with a tabulated detailed chemistry approach. (Doctoral Dissertation). Rouen, INSA. Retrieved from http://www.theses.fr/2010ISAM0001

Chicago Manual of Style (16^th Edition):

Vallinayagam pillai, Subramanian. “Modélisation de la combustion turbulente : application des méthodes de tabulation de la chimie détaillée l'allumage forcé : Numerical simulation of forced ignition using LES coupled with a tabulated detailed chemistry approach.” 2010. Doctoral Dissertation, Rouen, INSA. Accessed April 12, 2021. http://www.theses.fr/2010ISAM0001.

MLA Handbook (7^th Edition):

Vallinayagam pillai, Subramanian. “Modélisation de la combustion turbulente : application des méthodes de tabulation de la chimie détaillée l'allumage forcé : Numerical simulation of forced ignition using LES coupled with a tabulated detailed chemistry approach.” 2010. Web. 12 Apr 2021.

Vancouver:

Vallinayagam pillai S. Modélisation de la combustion turbulente : application des méthodes de tabulation de la chimie détaillée l'allumage forcé : Numerical simulation of forced ignition using LES coupled with a tabulated detailed chemistry approach. [Internet] [Doctoral dissertation]. Rouen, INSA; 2010. [cited 2021 Apr 12]. Available from: http://www.theses.fr/2010ISAM0001.

Council of Science Editors:

Vallinayagam pillai S. Modélisation de la combustion turbulente : application des méthodes de tabulation de la chimie détaillée l'allumage forcé : Numerical simulation of forced ignition using LES coupled with a tabulated detailed chemistry approach. [Doctoral Dissertation]. Rouen, INSA; 2010. Available from: http://www.theses.fr/2010ISAM0001

University of Kentucky

28. Owens, Tyler. Flame Stabilization of a Premixed Jet in Vitiated Coflow.

Degree: 2020, University of Kentucky

URL: https://uknowledge.uky.edu/me_etds/159

► Premixed staged combustion in gas turbine engines can reduce emissions by lowering peak flame temperatures but can also lead to different stability characteristics when compared… (more)

Subjects/Keywords: Autoignition; Premixed Combustion; Vitiated Flows; Laminar Flames; Flame Stabilization; Aerodynamics and Fluid Mechanics; Aerospace Engineering; Propulsion and Power

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Owens, T. (2020). Flame Stabilization of a Premixed Jet in Vitiated Coflow. (Masters Thesis). University of Kentucky. Retrieved from https://uknowledge.uky.edu/me_etds/159

Chicago Manual of Style (16^th Edition):

Owens, Tyler. “Flame Stabilization of a Premixed Jet in Vitiated Coflow.” 2020. Masters Thesis, University of Kentucky. Accessed April 12, 2021. https://uknowledge.uky.edu/me_etds/159.

MLA Handbook (7^th Edition):

Owens, Tyler. “Flame Stabilization of a Premixed Jet in Vitiated Coflow.” 2020. Web. 12 Apr 2021.

Vancouver:

Owens T. Flame Stabilization of a Premixed Jet in Vitiated Coflow. [Internet] [Masters thesis]. University of Kentucky; 2020. [cited 2021 Apr 12]. Available from: https://uknowledge.uky.edu/me_etds/159.

Council of Science Editors:

Owens T. Flame Stabilization of a Premixed Jet in Vitiated Coflow. [Masters Thesis]. University of Kentucky; 2020. Available from: https://uknowledge.uky.edu/me_etds/159

University of Toronto

29. Joo, Hyun Il. Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures.

Degree: 2010, University of Toronto

URL: http://hdl.handle.net/1807/24775

►

An experimental study was conducted using axisymmetric co-flow laminar diffusion flames of methane-air, methane-oxygen and ethylene-air to examine the effect of pressure on soot formation… (more)

▼

An experimental study was conducted using axisymmetric co-flow laminar diffusion flames of methane-air, methane-oxygen and ethylene-air to examine the effect of pressure on soot formation and the structure of the temperature field. A liquid fuel burner was designed and built to observe the sooting behavior of methanol-air and n-heptane-air laminar diffusion flames at elevated pressures up to 50 atm. A non-intrusive, line-of-sight spectral soot emission (SSE) diagnostic technique was used to determine the temperature and the soot volume fraction of methane-air flames up to 60 atm, methane-oxygen flames up to 90 atm and ethylene-air flames up to 35 atm. The physical flame structure of the methane-air and methane-oxygen diffusion flames were characterized over the pressure range of 10 to 100 atm and up to 35 atm for ethylene-air flames. The flame height, marked by the visible soot radiation emission, remained relatively constant for methane-air and ethylene-air flames over their respected pressure ranges, while the visible flame height for the methane-oxygen flames was reduced by over 50 % between 10 and 100 atm. During methane-air experiments, observations of anomalous occurrence of liquid material formation at 60 atm and above were recorded. The maximum conversion of the carbon in the fuel to soot exhibited a strong power-law dependence on pressure. At pressures 10 to 30 atm, the pressure exponent is approximately 0.73 for methane-air flames. At higher pressures, between 30 and 60 atm, the pressure exponent is approximately 0.33. The maximum fuel carbon conversion to soot is 12.6 % at 60 atm. For methane-oxygen flames, the pressure exponent is approximately 1.2 for pressures between 10 and 40 atm. At pressures between 50 and 70 atm, the pressure exponent is about -3.8 and approximately -12 for 70 to 90 atm. The maximum fuel carbon conversion to soot is 2 % at 40 atm. For ethylene-air flames, the pressure exponent is approximately 1.4 between 10 and 30 atm. The maximum carbon conversion to soot is approximately 6.5 % at 30 atm and remained constant at higher pressures.

PhD

Advisors/Committee Members: Gulder, Omer L., Aerospace Science and Engineering.

Subjects/Keywords: soot formation; high pressure combustion; laminar diffusion flames; 0538

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Joo, H. I. (2010). Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures. (Doctoral Dissertation). University of Toronto. Retrieved from http://hdl.handle.net/1807/24775

Chicago Manual of Style (16^th Edition):

Joo, Hyun Il. “Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures.” 2010. Doctoral Dissertation, University of Toronto. Accessed April 12, 2021. http://hdl.handle.net/1807/24775.

MLA Handbook (7^th Edition):

Joo, Hyun Il. “Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures.” 2010. Web. 12 Apr 2021.

Vancouver:

Joo HI. Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures. [Internet] [Doctoral dissertation]. University of Toronto; 2010. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/1807/24775.

Council of Science Editors:

Joo HI. Soot Formation in Non-premixed Laminar Flames at Subcritical and Supercritical Pressures. [Doctoral Dissertation]. University of Toronto; 2010. Available from: http://hdl.handle.net/1807/24775

University of Toronto

30. Veshkini, Armin. Understanding Soot Particle Growth Chemistry and Particle Sizing Using a Novel Soot Growth and Formation Model.

Degree: PhD, 2015, University of Toronto

URL: http://hdl.handle.net/1807/71398

► Research efforts are focused on advancing soot modeling in laminar flames using a detailed sectional aerosol dynamic model, toward an end goal of developing a… (more)

▼ Research efforts are focused on advancing soot modeling in laminar flames using a detailed sectional aerosol dynamic model, toward an end goal of developing a robust model applicable to a wide range of conditions. The effects of the soot coalescence process on soot particle diameter predictions are studied. Two coalescence models based on different merging mechanisms are implemented into the soot model. The models are applied to a laminar ethylene/air diffusion flame, and comparisons are made with experimental data to validate the models. The implementation of coalescence models significantly improves the agreement of prediction of particle diameters with the experimental data. A comprehensive study follows in which a function for surface reactivity of soot particles is developed to have a single model able to predict soot in many coflow ethylene/air flames. This study investigates how the surface reactivity of soot particles varies with particle thermal age. The surface reactivity function is applied to coflow diffusion flames with varying fuel/air ratios and fuel dilution, and to partially premixed coflow flames for a range of equivalence ratios. Comparisons are made with experimental data to validate the model. Good agreement is seen between numerical predictions and experimental measurements for soot volume fraction on the annular regions of the flames. The final part of this thesis explores the role of PAH-soot modeling on burner stabilized stagnation premixed flames and a coflow diffusion flame. Two chemical mechanisms are employed to model both flames. It is found that one of the mechanisms gives more accurate description of the PAH chemistry in premixed flames while the other improves the agreement of soot predictions in diffusion flames and the results and conclusion are drastically effected by the choice of PAH mechanism. An equilibrium based condensation efficiency model is developed and combined with a reversible nucleation model to predict soot formation in both premixed and nonpremixed flames. Compared to the measured data, soot PSDs are reasonably well predicted. Effects of different soot formation processes on PSD predictions are characterized. In the diffusion flame, employing a reversible nucleation model leads to a shift in onset of soot formation. Advisors/Committee Members: Thomson, Murray J, Dworkin, Seth B, Mechanical and Industrial Engineering.

Subjects/Keywords: Laminar Premixed and Diffusion Flames; Soot Coalescence; Soot Condensation; Soot Formation Modeling; Soot Nucleation; Soot Surface Growth; 0548

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Veshkini, A. (2015). Understanding Soot Particle Growth Chemistry and Particle Sizing Using a Novel Soot Growth and Formation Model. (Doctoral Dissertation). University of Toronto. Retrieved from http://hdl.handle.net/1807/71398

Chicago Manual of Style (16^th Edition):

Veshkini, Armin. “Understanding Soot Particle Growth Chemistry and Particle Sizing Using a Novel Soot Growth and Formation Model.” 2015. Doctoral Dissertation, University of Toronto. Accessed April 12, 2021. http://hdl.handle.net/1807/71398.

MLA Handbook (7^th Edition):

Veshkini, Armin. “Understanding Soot Particle Growth Chemistry and Particle Sizing Using a Novel Soot Growth and Formation Model.” 2015. Web. 12 Apr 2021.

Vancouver:

Veshkini A. Understanding Soot Particle Growth Chemistry and Particle Sizing Using a Novel Soot Growth and Formation Model. [Internet] [Doctoral dissertation]. University of Toronto; 2015. [cited 2021 Apr 12]. Available from: http://hdl.handle.net/1807/71398.

Council of Science Editors:

Veshkini A. Understanding Soot Particle Growth Chemistry and Particle Sizing Using a Novel Soot Growth and Formation Model. [Doctoral Dissertation]. University of Toronto; 2015. Available from: http://hdl.handle.net/1807/71398

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations