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Texas A&M University
1.
Muthu Narayanan, Aditya.
Investigation of the Difference in Cool Flame Characteristics between Petroleum Diesel and Soybean Biodiesel Operating in Low Temperature Combustion Mode.
Degree: MS, Mechanical Engineering, 2014, Texas A&M University
URL: http://hdl.handle.net/1969.1/151940 
► One of the promising solutions to rising emission standards is the in-cylinder emission reduction, through low temperature combustion. Low temperature combustion defeats conventional soot-NOx trade…
(more)
▼ One of the promising solutions to rising emission standards is the in-cylinder emission reduction, through low temperature combustion. Low temperature combustion defeats conventional soot-NOx trade off by simultaneous reduction of both emissions by controlling the in-cylinder temperature below the Soot and NOx forming temperature zones.
The use of low temperature combustion strategy phases the combustion into the expansion stroke, making the entire combustion process highly sensitive to start of high temperature combustion. Early start of high temperature combustion results in the advancement of combustion, resulting in higher in-cylinder temperature and pressure promoting the formation of oxides of nitrogen. Delayed start of combustion results in the retardation of the high temperature combustion further into the expansion stroke the first stage combustion, in this case
cool flame combustion, has an important role to play in the phasing of high temperature combustion, associated emissions and efficiency.
The focus of this study is to investigate the difference in the
cool flame combustion characteristics between petroleum diesel and soybean biodiesel, when operating in low temperature combustion mode. Previous studies have attributed the absence of the
cool flame in biodiesel purely due to oxygen content of the biodiesel. Cycle-to-cycle variation, exhaust gas constituents, rail pressure and fuel penetration length were analyzed to determine the causes for difference in the
cool flame characteristic between the two fuels. The result of the analysis was that
cool flame combustion is present in all combustion processes and not a product of systematic error or due to the combustion of the partially combusted species in the recirculated exhaust gas. It does not entirely depend on the chemical composition of fuel and rather on the in-cylinder conditions in particular the ambient oxygen concentration. Lower ambient oxygen concentration causes the
cool flame to advance with respect to the high temperature heat release, making it visible in the heat release profile. The appearance of the
cool flame at increased rail pressure in biodiesel does not cause a change in the trend of ignition delay, unburned hydrocarbon or carbon monoxide with respect to rail pressure. It only results in the retardation of high temperature combustion, further into the expansion stroke.
Low temperature combustion defeats conventional soot-NOx trade off by simultaneous reduction of both emissions by controlling the in-cylinder temperature below the Soot and NOx forming temperature zones. In this study, low temperature combustion is achieved with the use of high exhaust gas recirculation circulation and late injection timing, phasing the combustion in the expansion stroke.
The use of low temperature combustion strategy phases the combustion into the expansion stroke, making the entire combustion process highly sensitive to start of high temperature combustion. Early start of high temperature combustion results in the advancement…
Advisors/Committee Members: Jacobs, Timothy John (advisor), Alvarado, Jorge (committee member), Caton, Jerald (committee member).
Subjects/Keywords: Low temperature combustion; cool flame
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APA (6th Edition):
Muthu Narayanan, A. (2014). Investigation of the Difference in Cool Flame Characteristics between Petroleum Diesel and Soybean Biodiesel Operating in Low Temperature Combustion Mode. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151940
Chicago Manual of Style (16th Edition):
Muthu Narayanan, Aditya. “Investigation of the Difference in Cool Flame Characteristics between Petroleum Diesel and Soybean Biodiesel Operating in Low Temperature Combustion Mode.” 2014. Masters Thesis, Texas A&M University. Accessed April 13, 2021.
http://hdl.handle.net/1969.1/151940.
MLA Handbook (7th Edition):
Muthu Narayanan, Aditya. “Investigation of the Difference in Cool Flame Characteristics between Petroleum Diesel and Soybean Biodiesel Operating in Low Temperature Combustion Mode.” 2014. Web. 13 Apr 2021.
Vancouver:
Muthu Narayanan A. Investigation of the Difference in Cool Flame Characteristics between Petroleum Diesel and Soybean Biodiesel Operating in Low Temperature Combustion Mode. [Internet] [Masters thesis]. Texas A&M University; 2014. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1969.1/151940.
Council of Science Editors:
Muthu Narayanan A. Investigation of the Difference in Cool Flame Characteristics between Petroleum Diesel and Soybean Biodiesel Operating in Low Temperature Combustion Mode. [Masters Thesis]. Texas A&M University; 2014. Available from: http://hdl.handle.net/1969.1/151940
Drexel University
2.
Foster, Michael Robert.
Earth, Partial, and Reduced Gravity Experiments and Numerical Work on Propane-Oxygen Cool Flames at Sub-atmospheric Pressures.
Degree: 2006, Drexel University
URL: http://hdl.handle.net/1860/1111
► Natural convection plays an important role in nearly all terrestrial (1g), unstirred, static reactor cool flame and low-temperature auto-ignition studies. At near-zero gravity, however, Rayleigh…
(more)
▼ Natural convection plays an important role in nearly all terrestrial (1g), unstirred, static reactor cool flame and low-temperature auto-ignition studies. At near-zero gravity, however, Rayleigh numbers (Ra) less than the critical Ra for onset of buoyant convection can be achieved and the effects of convection can be suppressed. In this case, transport occurs strictly through diffusive fluxes of heat and species. To systematically vary the relative importance of natural convection versus diffusive transport without varying the mixture stoichiometry, reactor pressure, or vessel size, low-temperature reactions and cool flames are studied experimentally in a closed, unstirred, static reactor at 1g and aboard NASA’s KC-135A subject to different gravitational accelerations (Martian—0.38g, Lunar—0.16g, and reduced-gravity—10−2g).Representative results will be presented on the visible light emission, the temperaturehistories, and the pressure histories at temperatures ranging from 593–623 K (320–350◦C) in sub-atmospheric propane:oxygen premixtures. The results are compared qualitatively to numerical predictions derived from solutions to the coupled species, energy, and incompressible Navier-Stokes equations using a Gray-Yang skeletal kinetic mechanism.
M.S., Mechanical Engineering and Mechanics – Drexel University, 2006
Advisors/Committee Members: Pearlman, Howard.
Subjects/Keywords: Cool flame; Combustion
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APA (6th Edition):
Foster, M. R. (2006). Earth, Partial, and Reduced Gravity Experiments and Numerical Work on Propane-Oxygen Cool Flames at Sub-atmospheric Pressures. (Thesis). Drexel University. Retrieved from http://hdl.handle.net/1860/1111
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Foster, Michael Robert. “Earth, Partial, and Reduced Gravity Experiments and Numerical Work on Propane-Oxygen Cool Flames at Sub-atmospheric Pressures.” 2006. Thesis, Drexel University. Accessed April 13, 2021.
http://hdl.handle.net/1860/1111.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Foster, Michael Robert. “Earth, Partial, and Reduced Gravity Experiments and Numerical Work on Propane-Oxygen Cool Flames at Sub-atmospheric Pressures.” 2006. Web. 13 Apr 2021.
Vancouver:
Foster MR. Earth, Partial, and Reduced Gravity Experiments and Numerical Work on Propane-Oxygen Cool Flames at Sub-atmospheric Pressures. [Internet] [Thesis]. Drexel University; 2006. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1860/1111.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Foster MR. Earth, Partial, and Reduced Gravity Experiments and Numerical Work on Propane-Oxygen Cool Flames at Sub-atmospheric Pressures. [Thesis]. Drexel University; 2006. Available from: http://hdl.handle.net/1860/1111
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Princeton University
3.
Reuter, Christopher Bryan.
Chemistry and Dynamics of Counterflow Cool Flames
.
Degree: PhD, 2019, Princeton University
URL: http://arks.princeton.edu/ark:/88435/dsp01765374239
► Cool flame experiments offer an unexplored platform in addressing challenges relevant to the design of advanced engines. Advanced engine designs often focus on premixed or…
(more)
▼ Cool flame experiments offer an unexplored platform in addressing challenges relevant to the design of advanced engines. Advanced engine designs often focus on premixed or partially premixed strategies involving reduced
flame temperatures and, consequently, near-limit combustion with heightened sensitivity to the fuel reactivity and ignition timing. Despite the emissions and efficiency advantages, however, these designs have not been widely implemented due to the limited knowledge of the combustion chemistry required to operate them. A complete understanding of the chemical reactivity of real transportation fuels has been particularly difficult to achieve when considering the complexity of low-temperature combustion phenomena. By investigating low-temperature
cool flames in counterflow burners, this dissertation advances the fundamental understanding of the chemistry and dynamics of both nonpremixed and premixed
cool flames.
In the first section of this dissertation, the counterflow
cool flame platform is presented as an important tool in the quantitative validation of chemical kinetic models at low temperatures. Measurements of the nonpremixed
cool flame extinction limits are shown to magnify relatively small differences in low-temperature chemistry, giving the platform a potential use for screening the reactivity of different fuels. It is found that kinetic model predictions of the
cool flame extinction limits cannot reproduce experimental measurements accurately due to their inability to capture low-temperature heat release rates in
cool flames. An updated kinetic model for dimethyl ether/methane mixtures is developed and validated by targeting reactions disproportionally important to
cool flame extinction.
In the second part of the dissertation, the dynamics of both
cool flames and hot flames are investigated. The structure and stability of lean premixed
cool flames are measured over various conditions, and it is observed that
cool flames can sometimes burn under conditions that hot flames cannot, resulting in an extension of the lower flammability limits. In some cases, hot flames can extinguish into
cool flames via a transitional double
flame structure, composed of a leading
cool flame and a trailing hot
flame. The interactions between double flames and vortices are also investigated, revealing new and interesting transient
flame structures. These findings highlight the relevance of
cool flames to near-limit combustion.
Advisors/Committee Members: Ju, Yiguang (advisor).
Subjects/Keywords: Cool flame;
Counterflow flame;
Dimethyl ether;
Extinction limit;
Low-temperature chemistry;
Ozone
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APA (6th Edition):
Reuter, C. B. (2019). Chemistry and Dynamics of Counterflow Cool Flames
. (Doctoral Dissertation). Princeton University. Retrieved from http://arks.princeton.edu/ark:/88435/dsp01765374239
Chicago Manual of Style (16th Edition):
Reuter, Christopher Bryan. “Chemistry and Dynamics of Counterflow Cool Flames
.” 2019. Doctoral Dissertation, Princeton University. Accessed April 13, 2021.
http://arks.princeton.edu/ark:/88435/dsp01765374239.
MLA Handbook (7th Edition):
Reuter, Christopher Bryan. “Chemistry and Dynamics of Counterflow Cool Flames
.” 2019. Web. 13 Apr 2021.
Vancouver:
Reuter CB. Chemistry and Dynamics of Counterflow Cool Flames
. [Internet] [Doctoral dissertation]. Princeton University; 2019. [cited 2021 Apr 13].
Available from: http://arks.princeton.edu/ark:/88435/dsp01765374239.
Council of Science Editors:
Reuter CB. Chemistry and Dynamics of Counterflow Cool Flames
. [Doctoral Dissertation]. Princeton University; 2019. Available from: http://arks.princeton.edu/ark:/88435/dsp01765374239
King Abdullah University of Science and Technology
4.
Alfazazi, Adamu.
Autoignition chemistry of liquid and gaseous fuels in non-premixed systems.
Degree: Physical Science and Engineering (PSE) Division, 2018, King Abdullah University of Science and Technology
URL: http://hdl.handle.net/10754/628739
► Heat-release in CI engines occurs in the presence of concentration and temperature gradients. Recognizing the need for a validation of chemical kinetic models in transport-affected…
(more)
▼ Heat-release in CI engines occurs in the presence of concentration and temperature gradients. Recognizing the need for a validation of chemical kinetic models in transport-affected systems, this study employs non-premixed systems to better understand complex couplings between low/high temperature oxidation kinetics and diffusive transport. This dissertation is divided into two sections.
In the first section, a two-stage Lagrangian model compares model prediction of ignition delay time and experimental data from the KAUST ignition quality tester, and ignition data for liquid sprays in constant volume combustion chambers. The TSL employed in this study utilizes detailed chemical kinetics while also simulating basic mixing processes. The TSL model was found to be efficient in simulating IQT in long ignition delay time fuels; it was also effective in CVCC experiments with high injection pressures, where physical processes contributed little to ignition delay time.
In section two, an atmospheric pressure counterflow burner was developed and fully validated. The counterflow burner was employed to examine the effects of molecular structure on low/high temperature reactivity of various fuels in transport-affected systems. These effects were investigated through measurement of conditions of extinction and ignition of various fuel/oxidizer mixtures. Data generated were used to validate various chemical kinetic models in diffusion flames. Where necessary, suggestions were made for improving these models.
For hot flames studies, tested fuels included C3-C4 alcohols and six FACE gasoline fuels. Results for alcohols indicated that the substituted alcohols were less reactive than the normal alcohols. The ignition temperature of FACE gasoline was found to be nearly identical, while there was a slight difference in their extinction limits. Predictions by Sarathy et al. (2014) alcohol combustion model, and by the gasoline surrogate model (Sarathy et al., 2015), agreed with the experimental data. For
cool diffusion flames studies, tested fuels included butane isomers, naphtha, gasolines and their surrogates. Results revealed that the addition of ozone successfully established
cool flames in the fuels at low and moderate strain rates. Numerical simulations were performed to replicate the extinction limits of the
cool flames of butane isomers. The model captured experimental trends for both fuels; but over-predicted their extinction limits.
Advisors/Committee Members: Sarathy, Mani (advisor), Peinemann, Klaus-Viktor (committee member), Roberts, William L. (committee member), Kuti, Olawole A. (committee member).
Subjects/Keywords: Non-Premixed; Combustion; Cool Diffusion Flame; Hot Diffusion Flame; TSL; Two-Stage Lagrangian Model
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APA (6th Edition):
Alfazazi, A. (2018). Autoignition chemistry of liquid and gaseous fuels in non-premixed systems. (Thesis). King Abdullah University of Science and Technology. Retrieved from http://hdl.handle.net/10754/628739
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Alfazazi, Adamu. “Autoignition chemistry of liquid and gaseous fuels in non-premixed systems.” 2018. Thesis, King Abdullah University of Science and Technology. Accessed April 13, 2021.
http://hdl.handle.net/10754/628739.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Alfazazi, Adamu. “Autoignition chemistry of liquid and gaseous fuels in non-premixed systems.” 2018. Web. 13 Apr 2021.
Vancouver:
Alfazazi A. Autoignition chemistry of liquid and gaseous fuels in non-premixed systems. [Internet] [Thesis]. King Abdullah University of Science and Technology; 2018. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/10754/628739.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Alfazazi A. Autoignition chemistry of liquid and gaseous fuels in non-premixed systems. [Thesis]. King Abdullah University of Science and Technology; 2018. Available from: http://hdl.handle.net/10754/628739
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of New South Wales
5.
Krisman, Alexander.
Direct numerical simulation of diesel-relevant combustion.
Degree: Mechanical & Manufacturing Engineering, 2016, University of New South Wales
URL: http://handle.unsw.edu.au/1959.4/55498
;
https://unsworks.unsw.edu.au/fapi/datastream/unsworks:37862/SOURCE02?view=true
► Diesel combustion is a major contributor to global energy production. However, despite major improvements to diesel engine design, substantial gaps exist in the fundamental description…
(more)
▼ Diesel combustion is a major contributor to global energy production. However, despite major improvements to diesel engine design, substantial gaps exist in the fundamental description of the in-cylinder combustion process. This impedes the development of simple, predictive models which are necessary for designing improved combustion devices. In particular, only an under-resolved description of ignition and lifted
flame stabilisation exists, due to physical limitations of experimental measurements. Ignition and
flame stabilisation govern the formation of pollutants and combustion efficiency, and so a refined understanding is required. In this thesis, direct numerical simulation (DNS) techniques are applied to idealised configurations that represent facets of diesel combustion. A particular focus is applied to representing the correct thermochemical conditions which result in multi-stage autoignition and a negative temperature coefficient (NTC) regime of ignition delay times. The results were broadly consistent with prior experimental studies, but the well-resolved information also revealed details of several novel combustion features that have not been previously reported. Simulations of lifted laminar flames at NTC conditions with detailed dimethyl ether chemistry observed that edge
flame or hybrid edge
flame/autoignition structures can exist even at diesel-relevant autoignitive conditions, which raises the possibility that edge
flame propagation or a combination of edge
flame propagation and autoignition are responsible for diesel
flame stabilisation. The ignition of a two-dimensional mixing layer at NTC conditions in isotropic turbulence with detailed dimethyl ether chemistry was conducted. A complex ignition process was observed in which two-stage autoignition,
cool flames, and hybrid edge
flame/autoignition structures contributed to the overall ignition process. In particular, it was observed that the
cool flame influenced the timing and location of the high temperature ignition. A three-dimensional ignition at NTC conditions with global heptane chemistry was conducted. The results were consistent with the two-dimensional mixing layer results. The results also emphasised the importance of mixing rates in determining the location and timing of high temperature ignition. Overall, this thesis complements prior experimental results, identifies novel combustion features and highlights the substantial modelling challenge presented by diesel combustion.
Advisors/Committee Members: Hawkes, Evatt, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW, Kook, Sanghoon, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW.
Subjects/Keywords: Negative temperature coefficient; Direct numerical simulation; Diesel-relevant combustion; Triple flame; Two-stage ignition; Polybrachial flame; Tribrachial flame; Ignition; Cool flame; Edge flame
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APA (6th Edition):
Krisman, A. (2016). Direct numerical simulation of diesel-relevant combustion. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/55498 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:37862/SOURCE02?view=true
Chicago Manual of Style (16th Edition):
Krisman, Alexander. “Direct numerical simulation of diesel-relevant combustion.” 2016. Doctoral Dissertation, University of New South Wales. Accessed April 13, 2021.
http://handle.unsw.edu.au/1959.4/55498 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:37862/SOURCE02?view=true.
MLA Handbook (7th Edition):
Krisman, Alexander. “Direct numerical simulation of diesel-relevant combustion.” 2016. Web. 13 Apr 2021.
Vancouver:
Krisman A. Direct numerical simulation of diesel-relevant combustion. [Internet] [Doctoral dissertation]. University of New South Wales; 2016. [cited 2021 Apr 13].
Available from: http://handle.unsw.edu.au/1959.4/55498 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:37862/SOURCE02?view=true.
Council of Science Editors:
Krisman A. Direct numerical simulation of diesel-relevant combustion. [Doctoral Dissertation]. University of New South Wales; 2016. Available from: http://handle.unsw.edu.au/1959.4/55498 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:37862/SOURCE02?view=true
6.
Reuter, Christopher Bryan.
Chemistry and Dynamics of Counterflow Cool Flames
.
Degree: PhD, 2019, Princeton University
URL: http://arks.princeton.edu/ark:/88435/dsp01nv9355739
► Cool flame experiments offer an unexplored platform in addressing challenges relevant to the design of advanced engines. Advanced engine designs often focus on premixed or…
(more)
▼ Cool flame experiments offer an unexplored platform in addressing challenges relevant to the design of advanced engines. Advanced engine designs often focus on premixed or partially premixed strategies involving reduced
flame temperatures and, consequently, near-limit combustion with heightened sensitivity to the fuel reactivity and ignition timing. Despite the emissions and efficiency advantages, however, these designs have not been widely implemented due to the limited knowledge of the combustion chemistry required to operate them. A complete understanding of the chemical reactivity of real transportation fuels has been particularly difficult to achieve when considering the complexity of low-temperature combustion phenomena. By investigating low-temperature
cool flames in counterflow burners, this dissertation advances the fundamental understanding of the chemistry and dynamics of both nonpremixed and premixed
cool flames.
In the first section of this dissertation, the counterflow
cool flame platform is presented as an important tool in the quantitative validation of chemical kinetic models at low temperatures. Measurements of the nonpremixed
cool flame extinction limits are shown to magnify relatively small differences in low-temperature chemistry, giving the platform a potential use for screening the reactivity of different fuels. It is found that kinetic model predictions of the
cool flame extinction limits cannot reproduce experimental measurements accurately due to their inability to capture low-temperature heat release rates in
cool flames. An updated kinetic model for dimethyl ether/methane mixtures is developed and validated by targeting reactions disproportionally important to
cool flame extinction.
In the second part of the dissertation, the dynamics of both
cool flames and hot flames are investigated. The structure and stability of lean premixed
cool flames are measured over various conditions, and it is observed that
cool flames can sometimes burn under conditions that hot flames cannot, resulting in an extension of the lower flammability limits. In some cases, hot flames can extinguish into
cool flames via a transitional double
flame structure, composed of a leading
cool flame and a trailing hot
flame. The interactions between double flames and vortices are also investigated, revealing new and interesting transient
flame structures. These findings highlight the relevance of
cool flames to near-limit combustion.
Advisors/Committee Members: Ju, Yiguang (advisor).
Subjects/Keywords: Cool flame;
Counterflow flame;
Dimethyl ether;
Extinction limit;
Low-temperature chemistry;
Ozone
…13
1.3.1 Historical Cool Flame Studies… …13
1.3.2 Recent Cool Flame Studies… …3.3.2 Experimental Measurement of Nonpremixed Cool Flame Extinction .........39
3.3.3… …2015,
Dahms et al. 2017, Krisman et al. 2017). A cool flame governed by the same… …for experimental cool flame studies to complement
homogeneous reactor experiments and…
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Record Details
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APA ·
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MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Reuter, C. B. (2019). Chemistry and Dynamics of Counterflow Cool Flames
. (Doctoral Dissertation). Princeton University. Retrieved from http://arks.princeton.edu/ark:/88435/dsp01nv9355739
Chicago Manual of Style (16th Edition):
Reuter, Christopher Bryan. “Chemistry and Dynamics of Counterflow Cool Flames
.” 2019. Doctoral Dissertation, Princeton University. Accessed April 13, 2021.
http://arks.princeton.edu/ark:/88435/dsp01nv9355739.
MLA Handbook (7th Edition):
Reuter, Christopher Bryan. “Chemistry and Dynamics of Counterflow Cool Flames
.” 2019. Web. 13 Apr 2021.
Vancouver:
Reuter CB. Chemistry and Dynamics of Counterflow Cool Flames
. [Internet] [Doctoral dissertation]. Princeton University; 2019. [cited 2021 Apr 13].
Available from: http://arks.princeton.edu/ark:/88435/dsp01nv9355739.
Council of Science Editors:
Reuter CB. Chemistry and Dynamics of Counterflow Cool Flames
. [Doctoral Dissertation]. Princeton University; 2019. Available from: http://arks.princeton.edu/ark:/88435/dsp01nv9355739
7.
Bittle, Joshua.
Two-stage Ignition as an Indicator of Low Temperature Combustion in a Late Injection Pre-mixed Compression Ignition Control Strategy.
Degree: MS, Mechanical Engineering, 2011, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8945
► Internal combustion engines have dealt with increasingly restricted emissions requirements. After-treatment devices are successful in bringing emissions into compliance, but in-cylinder combustion control can reduce…
(more)
▼ Internal combustion engines have dealt with increasingly restricted emissions requirements. After-treatment devices are successful in bringing emissions into compliance, but in-cylinder combustion control can reduce their burden by reducing engine out emissions. For example, oxides of nitrogen (NOx) are diesel combustion exhaust species that are notoriously difficult to remove by after-treatment. In-cylinder conditions can be controlled for low levels of NOx, but this produces high levels of soot potentially leading to increased particulate matter (PM). The simultaneous reduction of NOx and PM can be realized through a combustion process known as low temperature combustion (LTC).
In this study, the typical definition of LTC as the defeat of the inverse relationship between soot and NOx is not applicable as a return to the soot-NOx tradeoff is observed with increasing exhaust gas recirculation (EGR). It is postulated that this effect is the result of an increase in the hot ignition equivalence ratio, moving the combustion event into a slightly higher soot formation region. This is important because a simple emissions based definition of LTC is no longer helpful. In this study, the manifestation of LTC in the calculated heat release profile is investigated.
The conditions classified as LTC undergo a two-stage ignition process. Two-stage ignition is characterized by an initial
cool-
flame reaction followed by typical hot ignition. In traditional combustion conditions, the ignition is fast enough that a
cool-
flame is not observed. By controlling initial conditions (pressure, temperature, and composition), the creation and duration of the
cool-
flame event is predictable. Further, the effect that injection timing and the exhaust gas recirculation level have on the controlling factors of the
cool-
flame reaction is well correlated to the duration of the
cool-
flame event. These two results allow the postulation that the presence of a sufficiently long
cool-
flame reaction indicates a combustion event that can be classified as low temperature combustion. A potential method for identifying low temperature combustion events using only the rate of heat release profile is theorized.
This study employed high levels of EGR and late injection timing to realize the LTC mode of ordinary petroleum diesel fuel. Under these conditions, and based on a 90 percent reduction in nitric oxide and no increase in smoke output relative to the chosen baseline condition, a two part criteria is developed that identifies the LTC classified conditions. The criteria are as follow: the combustion event of conventional petroleum diesel fuel must show a two-stage ignition process; the first stage (
cool-
flame reaction) must consume at least 2 percent of the normalized fuel energy before the hot ignition commences.
Advisors/Committee Members: Jacobs, Timothy (advisor), Caton, Jerald (committee member), Karpetis, Adonios (committee member).
Subjects/Keywords: Two-stage Ignition; Low Temperature Combustion; Diesel; NOx; Cool-flame; diagnostic tool
…4
1.2.1. Cool-flame Reactions… …8
1.2.3. Link between Cool-flame and Low Temperature Combustion ............ 9
1.3… …18
2.4.3. Cool-flame Property Support Calculations… …29
3.2.2. Cool-flame Properties… …the calculation of cool-flame duration and other locations of interest. ......... 23…
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APA ·
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APA (6th Edition):
Bittle, J. (2011). Two-stage Ignition as an Indicator of Low Temperature Combustion in a Late Injection Pre-mixed Compression Ignition Control Strategy. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8945
Chicago Manual of Style (16th Edition):
Bittle, Joshua. “Two-stage Ignition as an Indicator of Low Temperature Combustion in a Late Injection Pre-mixed Compression Ignition Control Strategy.” 2011. Masters Thesis, Texas A&M University. Accessed April 13, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8945.
MLA Handbook (7th Edition):
Bittle, Joshua. “Two-stage Ignition as an Indicator of Low Temperature Combustion in a Late Injection Pre-mixed Compression Ignition Control Strategy.” 2011. Web. 13 Apr 2021.
Vancouver:
Bittle J. Two-stage Ignition as an Indicator of Low Temperature Combustion in a Late Injection Pre-mixed Compression Ignition Control Strategy. [Internet] [Masters thesis]. Texas A&M University; 2011. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8945.
Council of Science Editors:
Bittle J. Two-stage Ignition as an Indicator of Low Temperature Combustion in a Late Injection Pre-mixed Compression Ignition Control Strategy. [Masters Thesis]. Texas A&M University; 2011. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8945
8.
Zhao, Peng.
Problems in Reaction Networks and Low Temperature Combustion
.
Degree: PhD, 2015, Princeton University
URL: http://arks.princeton.edu/ark:/88435/dsp01js956j144
► This dissertation consists of two parts, with Part I focusing on aspects of chemical reaction networks, including the construction of kinetic models for hydrocarbon oxidation…
(more)
▼ This dissertation consists of two parts, with Part I focusing on aspects of chemical reaction networks, including the construction of kinetic models for hydrocarbon oxidation and the development of a computational algorithm based on the concept of betweenness centrality for numerical combustion diagnostics and reduction of complex reaction networks, and Part II on low temperature combustion, specifically on the characteristics of low-temperature chemistry (LTC) in homogeneous combustion environments and its coupled effect with transport processes and flows under nonpremixed and premixed conditions.
In Part I of this dissertation research, a comprehensive chemical kinetic model for butene isomers in the intermediate-to-high temperature range is developed based on the understanding of C0 to C4 chemistry. High-fidelity nonpremixed counterflow ignition experiments as well as laminar
flame speed measurements under various pressures are acquired as the validation targets. Numerical simulations with detailed chemistry and transport under the experimental conditions were conducted, with the results compared with measurements to assess the adequacy of the kinetic models. Satisfactory performance of the model prediction is achieved for the current experimental results as well as the literature data such as those of flat
flame speciation, shock tube autoignition delay, and jet-stirred reactor species measurements.
Recognizing the complex nature of chemical kinetics, the prospect of using network science to analyze and simplify complex chemistry is explored. A numerical tool based on the concepts of the shortest path and betweenness centrality (BC) in network science is developed for computational diagnostics and model reduction, and has been applied to various combustion scenarios such methane oxidation, NOx formation, n-heptane LTC, and soot formation to yield useful reaction path information. Furthermore, with the index of importance of species assigned as the global BC from the reactants to the major products, skeletal mechanisms of flexible sizes have been generated by keeping species with higher BC values, showing good capability in reproducing autoignition delays and S-curves in perfectly-stirred reactors (PSR). Comparison of the BC and other methods such as directed relation graph (DRG), directed relation graph with error propagation (DRGEP) and sensitivity analysis (SA), demonstrates its satisfactory performance in generating accurate skeletal mechanisms.
In Part II of the dissertation research, the characteristics of LTC in homogeneous systems as well as the coupled effects with transport processes are investigated, recognizing that LTC has been extensively studied in homogeneous systems, such as shock tubes (ST), rapid compression machines (RCM), jet-stirred reactors (JSR) and flow reactors (FR), and has been demonstrated to be closely related to important combustion features such as the negative-temperature coefficient (NTC) in large hydrocarbon ignition and engine knocks. In this work, the…
Advisors/Committee Members: Law, Chung K (advisor).
Subjects/Keywords: centrality;
cool flame;
low temperature chemistry;
model reduction;
NTC;
reaction network
…161
VIII
6.2 Ignition and Propagation of the 1-D Planar Cool Flame… …164
6.3 Stretched Cool Flame in Counterflow - Computation… …169
6.4 Stretched Cool Flame in Counterflow: Experiment… …known as the cool flame phenomenon.
Then LTC is suppressed, the alkyl radicals generated would… …29
Laminar Flame Speeds, Counterflow Ignition, and Kinetic Modeling of the Butene
Isomers…
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APA (6th Edition):
Zhao, P. (2015). Problems in Reaction Networks and Low Temperature Combustion
. (Doctoral Dissertation). Princeton University. Retrieved from http://arks.princeton.edu/ark:/88435/dsp01js956j144
Chicago Manual of Style (16th Edition):
Zhao, Peng. “Problems in Reaction Networks and Low Temperature Combustion
.” 2015. Doctoral Dissertation, Princeton University. Accessed April 13, 2021.
http://arks.princeton.edu/ark:/88435/dsp01js956j144.
MLA Handbook (7th Edition):
Zhao, Peng. “Problems in Reaction Networks and Low Temperature Combustion
.” 2015. Web. 13 Apr 2021.
Vancouver:
Zhao P. Problems in Reaction Networks and Low Temperature Combustion
. [Internet] [Doctoral dissertation]. Princeton University; 2015. [cited 2021 Apr 13].
Available from: http://arks.princeton.edu/ark:/88435/dsp01js956j144.
Council of Science Editors:
Zhao P. Problems in Reaction Networks and Low Temperature Combustion
. [Doctoral Dissertation]. Princeton University; 2015. Available from: http://arks.princeton.edu/ark:/88435/dsp01js956j144
9.
Κατσουρίνης, Δημήτριος.
Προσομοίωση διεργασιών ετερογενών μειγμάτων με χρήση υπολογιστικών εργαλείων.
Degree: 2008, National Technical University of Athens (NTUA); Εθνικό Μετσόβιο Πολυτεχνείο (ΕΜΠ)
URL: http://hdl.handle.net/10442/hedi/16076
► The main objective of this thesis is to study fuel vapor, low temperature, chemical oxidation phenomena occurring inside reactors, where fuel sprays evaporate due to…
(more)
▼ The main objective of this thesis is to study fuel vapor, low temperature, chemical oxidation phenomena occurring inside reactors, where fuel sprays evaporate due to their interaction with preheated gas streams. The work focuses on the “stabilized cool - flame (SCF)” phenomenon, which allows subsequent use of premixed combustion technologies. This combination leads to an increase of the process overall efficiency, while at the same time reduces the formation of pollutants. In addition, the thesis highlights the advantages of combining experimental methods and CFD simulations, in order to understand in detail the occurring phenomena. Ιn the context of the present thesis, an “in-house” developed computational fluid dynamics (CFD) code has been extended to account for the simulation of turbulent, two - phase flow applications, utilizing the Euler-Euler methodology (2-Phase code / Version 2F / incorporating the two-fluid approach). On the other hand, the ability of - available in the literature - n - heptane reduced chemical kinetic mechanisms to describe the complex oxidative phenomena associated with the SCF phenomenon is investigated. In order to be able to compute the effect of low temperature chemical oxidation phenomena in the developing flow and thermal fields inside SCF reactors, an Ordinary Differential Equations (ODE) solver (adaptation of the “DVODE” solver package) incorporating a 7-step kinetic mechanism, is linked to the developed CFD code (2-Phase code / Version 2F). Hence, a composite CFD tool is introduced, based on the Direct Integration (DI) approach. The performance of the developed CFD code (2-Phase code / Version 2F / DI approach) is initially evaluated by numerically investigating diesel spray evaporation inside an atmospheric pressure SCF reactor. Experiments have also been conducted, resulting in a series of gas mixture temperature measurements, which represent the thermal field developing inside an atmospheric pressure SCF loop - type reactor with inbuilt re-circulation zones. Computational results are compared to the obtained temperature measurements, in order to assess the ability of the developed CFD tool, to accurately capture the main thermo-chemical characteristics occurring inside the reactor. It is concluded that the developed CFD tool (2-Phase code / Version 2F / DI approach) can reliably support geometry design and operation optimization of devices exploiting complex thermo - chemical phenomena, such as the SCF reactor. It is also evident that the implemented CFD approach provides useful information regarding the flow and thermal fields developing in regions inside the reactor, where measurements are not feasible due to the complexities of the examined geometry
Κύριο αντικείμενο της διατριβής αποτελεί η μελέτη των χημικών διεργασιών οξείδωσης ατμών καυσίμου στην περιοχή των χαμηλών θερμοκρασιών και ιδιαίτερα στο εσωτερικό αντιδραστήρων, όπου δέσμη σταγονιδίων (σπρέι) υγρού καυσίμου ατμοποιείται λόγω αλληλεπίδρασης της με θερμό ρεύμα οξειδωτικού συνεχούς μέσου. Έμφαση δίνεται στη…
Subjects/Keywords: Υπολογιστική ρευστοδυναμική, Κώδικας; Ροές; Ροές; Καύσιμα, Οξείδωση; Ψυχρή φλόγα, Φαινόμενο; Κανονικό επτάνιο, Μηχανισμοί χημικής κινητικής; Diesel, Ατμοποίηση δέσμης σταγονιδίων; Ψυχρή φλόγα, Αντιδραστήρες (Πειραματικές μετρήσεις); Computational fluid dynamics (CFD) code; Flows; Flows; Cool flame phenomenon; Fuel oxidation; N - Heptane, Chemical kinetic mechanisms of; Diesel spray evaporation; Cool flame, Reactors (Experimental measurements)
Record Details
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Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Κατσουρίνης, . . (2008). Προσομοίωση διεργασιών ετερογενών μειγμάτων με χρήση υπολογιστικών εργαλείων. (Thesis). National Technical University of Athens (NTUA); Εθνικό Μετσόβιο Πολυτεχνείο (ΕΜΠ). Retrieved from http://hdl.handle.net/10442/hedi/16076
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Κατσουρίνης, Δημήτριος. “Προσομοίωση διεργασιών ετερογενών μειγμάτων με χρήση υπολογιστικών εργαλείων.” 2008. Thesis, National Technical University of Athens (NTUA); Εθνικό Μετσόβιο Πολυτεχνείο (ΕΜΠ). Accessed April 13, 2021.
http://hdl.handle.net/10442/hedi/16076.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Κατσουρίνης, Δημήτριος. “Προσομοίωση διεργασιών ετερογενών μειγμάτων με χρήση υπολογιστικών εργαλείων.” 2008. Web. 13 Apr 2021.
Vancouver:
Κατσουρίνης . Προσομοίωση διεργασιών ετερογενών μειγμάτων με χρήση υπολογιστικών εργαλείων. [Internet] [Thesis]. National Technical University of Athens (NTUA); Εθνικό Μετσόβιο Πολυτεχνείο (ΕΜΠ); 2008. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/10442/hedi/16076.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Κατσουρίνης . Προσομοίωση διεργασιών ετερογενών μειγμάτων με χρήση υπολογιστικών εργαλείων. [Thesis]. National Technical University of Athens (NTUA); Εθνικό Μετσόβιο Πολυτεχνείο (ΕΜΠ); 2008. Available from: http://hdl.handle.net/10442/hedi/16076
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
. 
Open Access Theses and Dissertations
