+publisher:"Georgia Tech" +contributor:("Seitzman, Jerry")

Georgia Tech

1. Lambert, Alexander. LES of Turbulent Premixed Flame Kernel Formation and Development.

Degree: MS, Aerospace Engineering, 2020, Georgia Tech

► Spark ignition of flammable mixtures is highly sensitive to early and local conditions. Kernel formation and subsequent flame development are largely governed by turbulent conditions… (more)

Subjects/Keywords: Large Eddy Simulation; Spark Ignition; Turbulent Combustion; Computational Fluid Dynamics

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APA (6^th Edition):

Lambert, A. (2020). LES of Turbulent Premixed Flame Kernel Formation and Development. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/64079

Chicago Manual of Style (16^th Edition):

Lambert, Alexander. “LES of Turbulent Premixed Flame Kernel Formation and Development.” 2020. Masters Thesis, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/64079.

MLA Handbook (7^th Edition):

Lambert, Alexander. “LES of Turbulent Premixed Flame Kernel Formation and Development.” 2020. Web. 11 Apr 2021.

Vancouver:

Lambert A. LES of Turbulent Premixed Flame Kernel Formation and Development. [Internet] [Masters thesis]. Georgia Tech; 2020. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/64079.

Council of Science Editors:

Lambert A. LES of Turbulent Premixed Flame Kernel Formation and Development. [Masters Thesis]. Georgia Tech; 2020. Available from: http://hdl.handle.net/1853/64079

Georgia Tech

2. Sirignano, Matthew Davis. Experimental investigation of nitrogen oxide production in premixed reacting jets in a vitiated crossflow.

Degree: PhD, Aerospace Engineering, 2019, Georgia Tech

URL: http://hdl.handle.net/1853/62291

► The presented work describes the experimental investigation of nitrogen oxide (NOx) emissions from reacting jets in a vitiated crossflow (RJICF). It is motivated by interest… (more)

▼ The presented work describes the experimental investigation of nitrogen oxide (NOx) emissions from reacting jets in a vitiated crossflow (RJICF). It is motivated by interest in axial staging of combustion as an approach to reduce undesirable NOx emissions from gas turbine combustors operating at high flame temperatures (>1900K). In lean-premixed combustion, NOx levels are exponential functions of temperature and linear functions of residence time. Consequently, NOx production rates are high at such temperatures, and conventional combustor architectures are unable to simultaneously deliver low NOx and part-load operability. A RJICF is a natural means of implementing axial staging. Therefore, a fuller understanding of the governing processes and parameters regarding pollutant formation within this complex flow field is critical to the next generation of gas turbine technology advancement. It is clear that RJICF NOx production is a highly coupled process. A key challenge was decoupling the interdependent jet parameters in order to observe fundamental NOx production sensitivities. Data is presented for premixed jets injected into a vitiated crossflow of lean combustion products. The jets varied in: fuel selection (methane or ethane or a combination), equivalence ratio (0.8≤ϕjet≤9.0), momentum flux ratio (2≤J≤40), and exit geometry (pipe or nozzle). The crossflow temperatures ranged from 1350K – 1810K, and the reacting jets induced a bulk averaged temperature rise on the flow (ΔT) ranging from 75K – 350K. In addition, several data series were replicated with varied ethane/methane ratios at constant ϕjet to influence flame lifting independent of other parameters. Similarly, the jet exit geometry was varied to influence shear layer vortex growth rates. Overall, these data indicate that NOx emissions are largely determined by ΔT. However, significant variation was observed at constant ΔT levels. The data is consistent with the idea that this variation is controlled by the stoichiometry at which combustion actually occurs, referred to as ϕFlame. ϕFlame is influenced by ϕjet and pre-flame mixing of the jet and crossflow that, in turn, is a function of flame lift-off distance (LO), nozzle geometry, and crossflow temperature. The data highlights the importance of flame lifting as well as the potential importance of post-flame mixing effects. Both are complex problems and are not directly addressed in this work. Further work in these areas would significantly deepen understanding of the relevant phenomena in RJICF NOx production. Advisors/Committee Members: Lieuwen, Timothy C. (advisor), Seitzman, Jerry M. (committee member), Sun, Wenting (committee member), Steinberg, Adam (committee member), Laster, Ray (committee member).

Subjects/Keywords: NOx emissions; Gas turbines; Axial staging; Reacting jet in crossflow; Flame lifting; Hydrodynamic stability

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APA (6^th Edition):

Sirignano, M. D. (2019). Experimental investigation of nitrogen oxide production in premixed reacting jets in a vitiated crossflow. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62291

Chicago Manual of Style (16^th Edition):

Sirignano, Matthew Davis. “Experimental investigation of nitrogen oxide production in premixed reacting jets in a vitiated crossflow.” 2019. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/62291.

MLA Handbook (7^th Edition):

Sirignano, Matthew Davis. “Experimental investigation of nitrogen oxide production in premixed reacting jets in a vitiated crossflow.” 2019. Web. 11 Apr 2021.

Vancouver:

Sirignano MD. Experimental investigation of nitrogen oxide production in premixed reacting jets in a vitiated crossflow. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/62291.

Council of Science Editors:

Sirignano MD. Experimental investigation of nitrogen oxide production in premixed reacting jets in a vitiated crossflow. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/62291

Georgia Tech

3. Wei, Sheng. Effect of jet fuel composition on forced ignition in gas turbine combustors.

Degree: PhD, Aerospace Engineering, 2019, Georgia Tech

URL: http://hdl.handle.net/1853/61204

► The rapid growth in the aviation industry means increasing consumption of jet fuels, which is leading to greater interest in alternate and sustainable fuel sources.… (more)

▼ The rapid growth in the aviation industry means increasing consumption of jet fuels, which is leading to greater interest in alternate and sustainable fuel sources. The overall properties of these alternative fuels can be designed to meet existing standards. Nevertheless, the compositional differences between alternative and conventional fuels can lead to important variations in chemical and physical properties that impact engine performance. For example, ignition is of paramount importance to ensure reliable operation, especially in extreme conditions like cold starts and high altitude relights. For aircraft engines, ignition is the process of creating self-sustaining flames starting with a high-temperature source located near a combustor liner. This thesis is devoted to studying the differences in ignition behavior due to the variations in fuel composition. Fuel variations in ignition are studied in a well-characterized test facility that is readily amenable to modeling and simulation. The experiments employ a sunken-fire ignitor, like those typically employed in aircraft engines, operating at 15 Hz with ~1.25J spark energy. Performance differences among fuels are characterized through their ignition probabilities. To understand both the chemical and physical fuel effects on ignition, both prevaporized fuels and liquid fuel sprays are examined. The purpose of prevaporizing the fuel is to remove the process of liquid to gas transition and to focus on combustion chemistry alone. In the forced ignition of liquid fuel sprays, which mimics the situation encountered in aviation gas turbine engines, both physical and chemical properties of the fuel are relevant. Statistically significant differences between fuel ignition probabilities are observed. The droplet heating time is shown to correlate well with ignition probability. A particle Doppler phase analyzer (PDPA) is used to study droplet size distribution near the ignitor. These droplet distribution measurements can be useful for future CFD modeling. In addition to differentiating fuel performances through ignition probability, advanced diagnostic techniques are employed to understand the evolution of a spark kernels as it interacts with combustible mixtures. These techniques include high speed OH planar laser induced fluorescence, OH* chemiluminescence, and schlieren imaging. The results reveal the entrainment of ambient fluid into the convecting spark kernel, the decomposition of vaporized jet fuel in the high temperature kernel, and the transition from local “hot spots” within the spark kernel to a self-sustaining flame. In addition to the experiments, reduced order modeling is used to better understand the physics and chemistry of ignition for both prevaporized and liquid fuels. Chemical differences are found to depend on the relative distribution between intermediate breakdown products (e.g., ethylene, propene and isobutene) from the parent fuels, as these intermediates have drastically different chemical rates as a function of temperature. The energy transfer… Advisors/Committee Members: Seitzman, Jerry (advisor), Jagoda, Jechiel (committee member), Sun, Wenting (committee member), Oefelein, Joseph (committee member), Ranjan, Devesh (committee member).

Subjects/Keywords: Ignition; Combustion

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APA (6^th Edition):

Wei, S. (2019). Effect of jet fuel composition on forced ignition in gas turbine combustors. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/61204

Chicago Manual of Style (16^th Edition):

Wei, Sheng. “Effect of jet fuel composition on forced ignition in gas turbine combustors.” 2019. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/61204.

MLA Handbook (7^th Edition):

Wei, Sheng. “Effect of jet fuel composition on forced ignition in gas turbine combustors.” 2019. Web. 11 Apr 2021.

Vancouver:

Wei S. Effect of jet fuel composition on forced ignition in gas turbine combustors. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/61204.

Council of Science Editors:

Wei S. Effect of jet fuel composition on forced ignition in gas turbine combustors. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/61204

Georgia Tech

4. Muraleedharan, Murali Gopal gopal. Nanoscale heat transfer effects in the combustion of nanoenergetic materials.

Degree: PhD, Aerospace Engineering, 2018, Georgia Tech

URL: http://hdl.handle.net/1853/62223

► Metal-based composite energetic materials have substantially higher volumetric energy density when compared with monomolecular compounds such as trinitrotoluene (TNT). Micron-sized metal particles have been routinely… (more)

Subjects/Keywords: Nanoenergetic materials; Nanoscale heat transfer; Atomistic simulations; Molecular dynamics; Density functional theory

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APA (6^th Edition):

Muraleedharan, M. G. g. (2018). Nanoscale heat transfer effects in the combustion of nanoenergetic materials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62223

Chicago Manual of Style (16^th Edition):

Muraleedharan, Murali Gopal gopal. “Nanoscale heat transfer effects in the combustion of nanoenergetic materials.” 2018. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/62223.

MLA Handbook (7^th Edition):

Muraleedharan, Murali Gopal gopal. “Nanoscale heat transfer effects in the combustion of nanoenergetic materials.” 2018. Web. 11 Apr 2021.

Vancouver:

Muraleedharan MGg. Nanoscale heat transfer effects in the combustion of nanoenergetic materials. [Internet] [Doctoral dissertation]. Georgia Tech; 2018. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/62223.

Council of Science Editors:

Muraleedharan MGg. Nanoscale heat transfer effects in the combustion of nanoenergetic materials. [Doctoral Dissertation]. Georgia Tech; 2018. Available from: http://hdl.handle.net/1853/62223

Georgia Tech

5. Goh, Edwin. Reduced-order model for prediction of staged-combustor NOx emissions with detailed chemistry and finite-rate mixing.

Degree: PhD, Aerospace Engineering, 2020, Georgia Tech

URL: http://hdl.handle.net/1853/62848

► The ground power industry is targeting combined cycle plant efficiencies of 65% and above, which can be achieved primarily through higher combustor firing temperatures. Because… (more)

▼ The ground power industry is targeting combined cycle plant efficiencies of 65% and above, which can be achieved primarily through higher combustor firing temperatures. Because conventional combustors fail to meet NOx regulations at such temperatures, there is a pressing need for high-temperature, low-emissions combustors. In this regard, the staged combustion architecture is one such concept that shows promise due to its enhanced emissions performance and operational flexibility. The prohibitive cost of building prototypes relegates full-scale testing to the final stages of the product design cycle, while accurate models with turbulence and detailed chemistry cannot be used to efficiently explore the design space. Therefore, an efficient computational model is necessary to study a broad range of architectures. Despite extensive research on staged combustion and the related jet-in-crossflow (JICF) problem, there is little published research regarding the minimum NOx levels achievable by staged combustion architectures. The first contribution of this thesis presents a set of fundamental minimum NOx levels that are obtained by wrapping a constrained optimization routine around a reduced-order staged combustor model. For a firing temperature of 1975 K which corresponds to 65% efficiency, the minimum NO levels are determined to be roughly 1 ppm. Sensitivities of these minimum NOx levels to operational, geometric and computational parameters are identified and discussed. Recognizing that a turbulent flow field affects NOx chemistry primarily through mixing, the second contribution presents a reduced-order Limited Mixing and Entrainment (LiME) reactor model to predict emissions based on mixing and entrainment time scales. Molecular mixing is simulated based on the Interaction by Exchange with the Mean (IEM) model through interacting Lagrangian particles. The consensus is that better JICF mixing leads to lower NOx emissions, but little work has been done to characterize the effects of large-scale entrainment and small-scale mixing on NOx in isolation. The third contribution elucidates the sensitivity of NOx to mixing and entrainment time scales using reduced-order models and demonstrates a potential use case of this model in a constrained design optimization problem to identify minimum NOx levels under fixed entrainment rates. The impact of fuel and air staging on NOx under mixing and entrainment-limited scenarios is elucidated. Advisors/Committee Members: Seitzman, Jerry M. (advisor), Lieuwen, Tim C. (committee member), German, Brian (committee member), Isaac, Tobin (committee member), Oefelein, Joe (committee member).

Subjects/Keywords: Power generation; Emissions; Chemical reactor network; Combustion; Staged combustion; Oxides of nitrogen

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APA (6^th Edition):

Goh, E. (2020). Reduced-order model for prediction of staged-combustor NOx emissions with detailed chemistry and finite-rate mixing. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62848

Chicago Manual of Style (16^th Edition):

Goh, Edwin. “Reduced-order model for prediction of staged-combustor NOx emissions with detailed chemistry and finite-rate mixing.” 2020. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/62848.

MLA Handbook (7^th Edition):

Goh, Edwin. “Reduced-order model for prediction of staged-combustor NOx emissions with detailed chemistry and finite-rate mixing.” 2020. Web. 11 Apr 2021.

Vancouver:

Goh E. Reduced-order model for prediction of staged-combustor NOx emissions with detailed chemistry and finite-rate mixing. [Internet] [Doctoral dissertation]. Georgia Tech; 2020. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/62848.

Council of Science Editors:

Goh E. Reduced-order model for prediction of staged-combustor NOx emissions with detailed chemistry and finite-rate mixing. [Doctoral Dissertation]. Georgia Tech; 2020. Available from: http://hdl.handle.net/1853/62848

Georgia Tech

6. Ochs, Bradley Alan. Ignition, topology, and growth of turbulent premixed flames in supersonic flows.

Degree: PhD, Aerospace Engineering, 2019, Georgia Tech

URL: http://hdl.handle.net/1853/62313

► Supersonic combustion ramjets (scramjets) are currently the most efficient combustor technology for air breathing hypersonic flight, however, lack of fundamental understanding and numerous engineering challenges… (more)

▼ Supersonic combustion ramjets (scramjets) are currently the most efficient combustor technology for air breathing hypersonic flight, however, lack of fundamental understanding and numerous engineering challenges hinder regular deployment of these devices. This work addresses scramjet-relevant knowledge gaps in supersonic turbulent premixed combustion, including laser ignition, numerical modeling, and flame-compressibility interaction. One of the main contributions of this work is introduction of a new turbulent premixed flame arrangement where flame-compressibility interaction can be systematically explored: flame kernels in an expanding flow field. The scramjet flow path is replaced by a simplified channel geometry with a well characterized mean flow acceleration that mimics flow field expansion typically imposed on scramjet combustors to avoid thermal choking. Spherically expanding flames are created via laser ignition and subsequent flame growth and morphology are investigated using combined physical and numerical experiments. Pressure-density misalignment due to flame-compressibility interaction produces vorticity at the flame surface through baroclinic torque, i.e. flame-compressibility interaction acts like a turbulence source. The flame ultimately evolves into a reacting vortex ring that increases the flame speed and enhances reactant consumption. To explore the relative importance of turbulence and compressibility on flame dynamics, the Mach number (M=1.5,1.75,2), equivalence ratio (φ= 1.0,0.9,0.8,0.7), and root-mean-squared turbulent velocity (u'=3.98,4.14,4.45 m/s) are varied systematically. This work also introduces flame kernels in an expanding flow field as a canonical numerical validation test case for flame-compressibility interaction. Inaccuracies in simulation results are easily identified due to high flow velocity and simplicity of the problem. The numerical setup and models are scrutinized to minimize errors. Using the appropriately verified numerical models, simulation results show very reasonable agreement with experimental data. Validated simulations are instrumental in enhancing understanding of the underlying physics of supersonic flame kernels. Laser ignition studies in supersonic flows have historically focused on ignition of non-premixed fuels within cavity flame holders. This work introduces a far simpler and more tractable problem: laser ignition of a fully premixed supersonic gas. Ignition experiments with a range of laser settings are performed to determine supersonic breakdown and ignition probabilities, length of time the ignition event influences flame growth, and Mach number influence on the ignition process. The ignition event has a long-lasting effect on kernel growth, but the influence can be minimized by properly selecting the laser energy. Mach number has a minimal impact on the ignition process, but does affect the initial kernel shape due to flow field variations with Mach number. Kernel growth matches low speed studies closely at early times, but deviates at later times due… Advisors/Committee Members: Menon, Suresh (advisor), Ranjan, Devesh (committee member), Seitzman, Jerry (committee member), Sun, Wenting (committee member), Pitz, Robert (committee member), Carter, Campbell (committee member).

Subjects/Keywords: Hypersonics; Supersonic flows; Supersonic combustion; Laser ignition; Turbulent flames; Premixed flames

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APA (6^th Edition):

Ochs, B. A. (2019). Ignition, topology, and growth of turbulent premixed flames in supersonic flows. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62313

Chicago Manual of Style (16^th Edition):

Ochs, Bradley Alan. “Ignition, topology, and growth of turbulent premixed flames in supersonic flows.” 2019. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/62313.

MLA Handbook (7^th Edition):

Ochs, Bradley Alan. “Ignition, topology, and growth of turbulent premixed flames in supersonic flows.” 2019. Web. 11 Apr 2021.

Vancouver:

Ochs BA. Ignition, topology, and growth of turbulent premixed flames in supersonic flows. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/62313.

Council of Science Editors:

Ochs BA. Ignition, topology, and growth of turbulent premixed flames in supersonic flows. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/62313

Georgia Tech

7. Amato, Alberto. Leading points concepts in turbulent premixed combustion modeling.

Degree: PhD, Mechanical Engineering, 2014, Georgia Tech

URL: http://hdl.handle.net/1853/52247

► The propagation of premixed flames in turbulent flows is a problem of wide physical and technological interest, with a significant literature on their propagation speed… (more)

▼ The propagation of premixed flames in turbulent flows is a problem of wide physical and technological interest, with a significant literature on their propagation speed and front topology. While certain scalings and parametric dependencies are well understood, a variety of problems remain. One major challenge, and focus of this thesis, is to model the influence of fuel/oxidizer composition on turbulent burning rates. Classical explanations for augmentation of turbulent burning rates by turbulent velocity fluctuations rely on global arguments - i.e., the turbulent burning velocity increase is directly proportional to the increase in flame surface area and mean local burning rate along the flame. However, the development of such global approaches is complicated by the abundance of phenomena influencing the propagation of turbulent premixed flames. Emphasizing key governing processes and cutting-off interesting but marginal phenomena appears to be necessary to make further progress in understanding the subject. An alternative approach to understand turbulent augmentation of burning rates is based upon so-called "leading points", which are intrinsically local properties of the turbulent flame. Leading points concepts suggest that the key physical mechanism controlling turbulent burning velocities of premixed flames is the velocity of the points on the flame that propagate farthest out into the reactants. It is postulated that modifications in the overall turbulent combustion speed depend solely on modifications of the burning rate at the leading points since an increase (decrease) in the average propagation speed of these points causes more (less) flame area to be produced behind them. In this framework, modeling of turbulent burning rates can be thought as consisting of two sub-problems: the modeling of (1) burning rates at the leading points and of (2) the dynamics/statistics of the leading points in the turbulent flame. The main objective of this thesis is to critically address both aspects, providing validation and development of the physical description put forward by leading point concepts. To address the first sub-problem, a comparison between numerical simulations of one-dimensional laminar flames in different geometrical configurations and statistics from a database of direct numerical simulations (DNS) is detailed. In this thesis, it is shown that the leading portions of the turbulent flame front display a structure that on average can be reproduced reasonably well by results obtained from model geometries with the same curvature. However, the comparison between model laminar flame computations and highly curved flamelets is complicated by the presence of negative (i.e., compressive) strain rates, due to gas expansion. For the highest turbulent intensity investigated, local consumption speeds, curvatures, strain rates and flame thicknesses approach the maximum values obtained by the laminar model geometries, while other cases display substantially lower values. To address the second sub-problem, the… Advisors/Committee Members: Lieuwen, Timothy C. (advisor), Seitzman, Jerry M. (committee member), Genzale, Caroline (committee member), Yeung, P.K. (committee member), Bakhtin, Yuri (committee member).

Subjects/Keywords: Premixed flames; Turbulent combustion; Leading points; Flame stretch; G-equation

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APA (6^th Edition):

Amato, A. (2014). Leading points concepts in turbulent premixed combustion modeling. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/52247

Chicago Manual of Style (16^th Edition):

Amato, Alberto. “Leading points concepts in turbulent premixed combustion modeling.” 2014. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/52247.

MLA Handbook (7^th Edition):

Amato, Alberto. “Leading points concepts in turbulent premixed combustion modeling.” 2014. Web. 11 Apr 2021.

Vancouver:

Amato A. Leading points concepts in turbulent premixed combustion modeling. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/52247.

Council of Science Editors:

Amato A. Leading points concepts in turbulent premixed combustion modeling. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/52247

Georgia Tech

8. Coso, Alexandra Emelina. Preparing students to incorporate stakeholder requirements in aerospace vehicle design.

Degree: PhD, Aerospace Engineering, 2014, Georgia Tech

URL: http://hdl.handle.net/1853/51885

► The design of an aerospace vehicle system is a complex integration process driven by technological developments, stakeholder and mission needs, cost, and schedule. The vehicle… (more)

▼ The design of an aerospace vehicle system is a complex integration process driven by technological developments, stakeholder and mission needs, cost, and schedule. The vehicle then operates in an equally complex context, dependent on many aspects of the environment, the performance of stakeholders and the quality of the design itself. Satisfying the needs of all stakeholders is a complicated challenge for designers and engineers, and stakeholder requirements are, at times, neglected in design decisions. Thus, it is critical to examine how to better incorporate stakeholder requirements earlier and throughout the design process. The intent of this research is to (1) examine how stakeholder considerations are currently integrated into aerospace vehicle design practice and curricula, (2) design empirically-informed and theoretically-grounded educational interventions for an aerospace design capstone course, and (3) isolate the characteristics of the interventions and learning environment which support students’ integration of stakeholder considerations. The first research phase identified how stakeholder considerations are taken into account within an aerospace vehicle design firm and in current aerospace engineering design curricula. Interviews with aerospace designers revealed six conditions at the group, interaction and individual levels affecting the integration of stakeholder considerations. Examining current curricula, aerospace design education relies on quantitative measures. Thus, many students are not introduced to stakeholder considerations that are challenging to quantify. In addition, at the start of an aerospace engineering senior design capstone course, students were found to have some understanding of the customer and a few contextual considerations, but in general students did not see the impact of the broader context or of stakeholders outside of the customer. The second research phase comprised the design and evaluation of a Requirements Lab and Stakeholders in Design Labs, two in-class interventions implemented in a senior aircraft design capstone course. Further, a Stakeholders in Design rubric was developed to evaluate students’ design understanding and integration of stakeholder considerations and, as such, can be used as a summative assessment tool. The two interventions were evaluated using a multi-level framework to examine student capstone design projects, a written evaluation, and observations of students’ design team meetings. The findings demonstrated an increase in students’ awareness of a diverse group of stakeholders, but also perceptions that students appeared to only integrate stakeholder considerations in cases where interactions with stakeholders were possible and the design requirements had an explicit stakeholder focus. Particular aspects of the aircraft design learning environment such as the lack of explicit stakeholder requirements, the differences between the learning environment in the two semesters of the course, and the availability of tools impacted students’ integration… Advisors/Committee Members: Pritchett, Amy (advisor), German, Brian (committee member), Seitzman, Jerry (committee member), Newstetter, Wendy (committee member), Adams, Robin (committee member), Jacobsen, Alan (committee member).

Subjects/Keywords: Aerospace vehicle design; Engineering design education; Stakeholder considerations; Space vehicles; Design; Group decision making; Multiple criteria decision making

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APA (6^th Edition):

Coso, A. E. (2014). Preparing students to incorporate stakeholder requirements in aerospace vehicle design. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/51885

Chicago Manual of Style (16^th Edition):

Coso, Alexandra Emelina. “Preparing students to incorporate stakeholder requirements in aerospace vehicle design.” 2014. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/51885.

MLA Handbook (7^th Edition):

Coso, Alexandra Emelina. “Preparing students to incorporate stakeholder requirements in aerospace vehicle design.” 2014. Web. 11 Apr 2021.

Vancouver:

Coso AE. Preparing students to incorporate stakeholder requirements in aerospace vehicle design. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/51885.

Council of Science Editors:

Coso AE. Preparing students to incorporate stakeholder requirements in aerospace vehicle design. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/51885

Georgia Tech

9. Gao, Xiang. The effects of ozone addition on flame propagation and stabilization.

Degree: PhD, Aerospace Engineering, 2017, Georgia Tech

URL: http://hdl.handle.net/1853/59251

► Combustion plays a vital role in transportation and power generation. However, concerns of efficiency, emission, and operations at extreme conditions highlight the needs to enhance… (more)

▼ Combustion plays a vital role in transportation and power generation. However, concerns of efficiency, emission, and operations at extreme conditions highlight the needs to enhance combustion process. If the rate-limiting chemical pathways can be modified, the ignition and combustion process could be dramatically accelerated. Following this idea, addition of ozone (O3) is proposed as a potential solution. O3 is one of the strongest oxidizers. It can be efficiently and economically produced in situ at high pressures, and transported to the desired region from an injection location to modify fuel oxidization and control the combustion process. To serve as a basis for future application on practical combustion systems, this dissertation investigates the effects of O3 addition on two fundamental combustion processes: the propagation of laminar premixed flames and the stabilization of non- premixed jet flames in autoignitive environment. Previous studies have shown that O3 addition can enhance flame propagation, stability and ignition, but the dependence on pressure and temperature were not clear. Furthermore, few studies have been conducted on the effects of ozonolysis reactions, which are rapid even at room temperature for unsaturated hydrocarbons. The results presented in this dissertation are an attempt to address these questions. The effects of O3 addition on the propagation of laminar premixed flames are investigated with respect to pressure, initial temperature, O3 concentration and fuel kinetics. For alkane/air premixed laminar flames, high-pressure Bunsen flame experiments in the present work show that the enhancement in laminar flame speed (SL) increases with pressures. This is due to the fact that O3 decomposition, which releases reactive oxygen atoms, becomes a more dominant O3 consumption pathway at higher pressure. Simulations show that adding O3 at higher initial temperature is not as effective as lower initial temperatures. A nearly linear relation between the enhancement and O3 concentration is observed at room temperature and atmospheric pressure. If the fuel is changed from alkanes to C2H4, an unsaturated hydrocarbon species, ozonolysis reactions take place in the premixing process. When the heat released from ozonolysis reactions is lost, decrease in SL is observed. In contrast, if ozonolysis reaction are frozen, either by cooling the reactants or decreasing the pressure, enhancement of SL by O3 addition is observed. The study on flame stabilization with O3 addition is conducted with a non-premixed jet burner in a quartz tube using C2H4 as the fuel. At low-dilution conditions, autoignition events are initiated by ozonolysis reactions. The autoignition timescale is further investigated quantitatively. Overall, this timescale decreases as the inlet velocity increases. At such autoignitive conditions created by ozonolysis reactions, the stabilization of a lifted non-premixed flame is fundamentally different from non-autoignitive conditions. Propagation is enhanced due to the “preprocessing” of fuel by… Advisors/Committee Members: Sun, Wenting (advisor), Ombrello, Timothy (committee member), Seitzman, Jerry (committee member), Sankar, Lakshmi (committee member), Jagoda, Jechiel (committee member).

Subjects/Keywords: Ozone; Flame propagation; Flame stabilization; Ozonolysis

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APA (6^th Edition):

Gao, X. (2017). The effects of ozone addition on flame propagation and stabilization. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59251

Chicago Manual of Style (16^th Edition):

Gao, Xiang. “The effects of ozone addition on flame propagation and stabilization.” 2017. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/59251.

MLA Handbook (7^th Edition):

Gao, Xiang. “The effects of ozone addition on flame propagation and stabilization.” 2017. Web. 11 Apr 2021.

Vancouver:

Gao X. The effects of ozone addition on flame propagation and stabilization. [Internet] [Doctoral dissertation]. Georgia Tech; 2017. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/59251.

Council of Science Editors:

Gao X. The effects of ozone addition on flame propagation and stabilization. [Doctoral Dissertation]. Georgia Tech; 2017. Available from: http://hdl.handle.net/1853/59251

Georgia Tech

10. Marshall, Andrew. Turbulent flame propagation characteristics of high hydrogen content fuels.

Degree: PhD, Mechanical Engineering, 2015, Georgia Tech

URL: http://hdl.handle.net/1853/53859

► Increasingly stringent pollution and emission controls have caused a rise in the use of combustors operating under lean, premixed conditions. Operating lean (excess air) lowers… (more)

▼ Increasingly stringent pollution and emission controls have caused a rise in the use of combustors operating under lean, premixed conditions. Operating lean (excess air) lowers the level of nitrous oxides (NOx) emitted to the environment. In addition, concerns over climate change due to increased carbon dioxide (CO2) emissions and the need for energy independence in the United States have spurred interest in developing combustors capable of operating with a wide range of fuel compositions. One method to decrease the carbon footprint of modern combustors is the use of high hydrogen content (HHC) fuels. The objective of this research is to develop tools to better understand the physics of turbulent flame propagation in highly stretch sensitive premixed flames in order to predict their behavior at conditions realistic to the environment of gas turbine combustors. This thesis presents the results of an experimental study into the flame propagation characteristics of highly stretch-sensitive, turbulent premixed flames generated in a low swirl burner (LSB). This study uses a scaling law, developed in an earlier thesis from leading point concepts for turbulent premixed flames, to collapse turbulent flame speed data over a wide range of conditions. The flow and flame structure are characterized using high speed particle image velocimetry (PIV) over a wide range of fuel compositions, mean flow velocities, and turbulence levels. The first part of this study looks at turbulent flame speeds for these mixtures and applies the previously developed leading points scaling model in order to test its validity in an alternate geometry. The model was found to collapse the turbulent flame speed data over a wide range of fuel compositions and turbulence levels, giving merit to the leading points model as a method that can produce meaningful results with different geometries and turbulent flame speed definitions. The second part of this thesis examines flame front topologies and stretch statistics of these highly stretch sensitive, turbulent premixed flames. Instantaneous flame front locations and local flow velocities are used to calculate flame curvatures and tangential strain rates. Statistics of these two quantities are calculated both over the entire flame surface and also conditioned at the leading points of the flames. Results presented do not support the arguments made in the development of the leading points model. Only minor effects of fuel composition are noted on curvature statistics, which are mostly dominated by the turbulence. There is a stronger sensitivity for tangential strain rate statistics, however, time-averaged values are still well below the values hypothesized from the leading points model. The results of this study emphasize the importance of local flame topology measurements towards the development of predictive models of the turbulent flame speed. Advisors/Committee Members: Lieuwen, Tim C. (advisor), Seitzman, Jerry (committee member), Menon, Suresh (committee member), Genzale, Caroline (committee member), Zinn, Ben T. (committee member).

Subjects/Keywords: Turbulent flames; Premixed flames; Turbulent flame speed; High hydrogen; Stretch effects; Curvature; Tangential strain rate; Leading points; Fuel effects; Low swirl burner; Particle image velocimetry; Flame topology

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APA (6^th Edition):

Marshall, A. (2015). Turbulent flame propagation characteristics of high hydrogen content fuels. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/53859

Chicago Manual of Style (16^th Edition):

Marshall, Andrew. “Turbulent flame propagation characteristics of high hydrogen content fuels.” 2015. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/53859.

MLA Handbook (7^th Edition):

Marshall, Andrew. “Turbulent flame propagation characteristics of high hydrogen content fuels.” 2015. Web. 11 Apr 2021.

Vancouver:

Marshall A. Turbulent flame propagation characteristics of high hydrogen content fuels. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/53859.

Council of Science Editors:

Marshall A. Turbulent flame propagation characteristics of high hydrogen content fuels. [Doctoral Dissertation]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/53859

Georgia Tech

11. Quinlan, John Mathew. Investigation of driving mechanisms of combustion instabilities in liquid rocket engines via the dynamic mode decomposition.

Degree: PhD, Aerospace Engineering, 2015, Georgia Tech

URL: http://hdl.handle.net/1853/54343

► Combustion instability due to feedback coupling between unsteady heat release and natural acoustic modes can cause catastrophic failure in liquid rocket engines and to predict… (more)

▼ Combustion instability due to feedback coupling between unsteady heat release and natural acoustic modes can cause catastrophic failure in liquid rocket engines and to predict and prevent these instabilities the mechanisms that drive them must be further elucidated. With this goal in mind, the objective of this thesis was to develop techniques that improve the understanding of the specific underlying physical processes involved in these driving mechanisms. In particular, this work sought to develop a small-scale, optically accessible liquid rocket engine simulator and to apply modern, high-speed diagnostic techniques to characterize the reacting flow and acoustic field within the simulator. Specifically, high-speed (10 kHz), simultaneous data were acquired while the simulator was experiencing a 170 Hz combustion instability using particle image velocimetry, OH planar laser induced fluorescence, CH* chemiluminescence, and dynamic pressure measurements. In addition, this work sought to develop approaches to reduce the large quantities of data acquired, extracting key physical phenomena involved in the driving mechanisms. The initial data reduction approach was chosen based on the fact that the combustion instability problem is often simplified to the point that it can be characterized by an approximately linear constant coefficient system of equations. Consistent with this simplification, the experimental data were analyzed by the dynamic mode decomposition method. The developed approach to apply the dynamic mode decomposition to simultaneously acquired data located a coupled hydrodynamic/combustion/acoustic mode at 1017 Hz. On the other hand, the dynamic mode decomposition's assumed constant operator approach failed to locate any modes of interest near 170 Hz. This led to the development of two new data analysis techniques based on the dynamic mode decomposition and Floquet theory that assume that the experiment is governed by a linear, periodic system of equations. The new periodic-operator data analysis techniques, the Floquet decomposition and the ensemble Floquet decomposition, approximate, from experimental data, the largest moduli Floquet multipliers, which determine the stability of the periodic solution trajectory of the system. The unstable experiment dataset was analyzed with these techniques and the ensemble Floquet decomposition analysis found a large modulus Floquet multiplier and associated mode with a frequency of 169.6 Hz. Furthermore, the approximate Rayleigh criterion indicated that this mode was unstable with respect to combustion instability. Overall, based on the positive finding that the ensemble Floquet decomposition was able to locate an unstable combustion mode at 170 Hz when the operator's time period was set to 1 ms, suggests that the dynamic mode decomposition based 1017 Hz mode parametrically forces the 170 Hz mode, resulting in what could be characterized as a parametric combustion instability. Advisors/Committee Members: Zinn, Ben T. (advisor), Dieci, Luca (committee member), Lieuwen, Tim (committee member), Menon, Suresh (committee member), Seitzman, Jerry M. (committee member).

Subjects/Keywords: CI; LRE; DMD; Floquet; Floquet decomposition; FD; EFD; POD; Combustion; Stability; Instability; Acoustic; Liquid rocket; Dynamic mode decomposition; Ensemble floquet decomposition; Periodic; Vibrations; Time-varying; Eigenvalues

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APA (6^th Edition):

Quinlan, J. M. (2015). Investigation of driving mechanisms of combustion instabilities in liquid rocket engines via the dynamic mode decomposition. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54343

Chicago Manual of Style (16^th Edition):

Quinlan, John Mathew. “Investigation of driving mechanisms of combustion instabilities in liquid rocket engines via the dynamic mode decomposition.” 2015. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/54343.

MLA Handbook (7^th Edition):

Quinlan, John Mathew. “Investigation of driving mechanisms of combustion instabilities in liquid rocket engines via the dynamic mode decomposition.” 2015. Web. 11 Apr 2021.

Vancouver:

Quinlan JM. Investigation of driving mechanisms of combustion instabilities in liquid rocket engines via the dynamic mode decomposition. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/54343.

Council of Science Editors:

Quinlan JM. Investigation of driving mechanisms of combustion instabilities in liquid rocket engines via the dynamic mode decomposition. [Doctoral Dissertation]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/54343

Georgia Tech

12. Kundu, Reema. Impact of engine icing on jet engine compressor flow dynamics.

Degree: PhD, Aerospace Engineering, 2015, Georgia Tech

URL: http://hdl.handle.net/1853/54870

► Core engine icing has been recognized to affect a wide variety of engines since the 1990's. This previously unrecognized form of icing occurs in flights… (more)

▼ Core engine icing has been recognized to affect a wide variety of engines since the 1990's. This previously unrecognized form of icing occurs in flights through high altitude convective regions and vicinity of thunderstorms. Engine icing events involve power loss or damage associated to the engine core, namely instabilities such as compressor surge, stall, engine rollback and even combustor flameout events. The effects on compressor performance are significant in understanding the response of the engine to atmospheric ice ingestion. A one-dimensional axisymmetric flow model is used to simulate the continuous phase through the compressor. The steady state operation of dry air is validated with an industrial database. By changing an exit throttle, the point where the dry compressor mass flow rate slowly starts to drop, is predicted. The stage that is the first to locally collapse, causing the remaining stages and eventually the complete compressor failure, is determined. The continuous flow model is then coupled with a Lagrangian model for the discrete phase in a framework that conserves mass, momentum and energy. From numerical simulations of the coupled, continuous-discrete phase flow model, it is observed that a rematching of the stages across the compressor occurs with increasing ice flow rates to accommodate loss of energy to the ice flow. The migration of the operating point towards the stall point at the rear stage eventually causes the compressor to stall. The onset of stall is characterized by initial oscillations followed by a rapid decay of pressures of the last stage with the instability traveling quickly towards the front of the compressor. Effectively, a reduction in the compressor stall margin is observed as the ice flow rate increases. Further, the relevance of factors such as blockage due to discrete particles and break/splash semi-empirical models in the icing physics, are analyzed through parametric studies. Conclusions are drawn that underscore the influence of the assumptions and models in prediction of the flow behavior in the presence of ice ingestion. Smaller ice crystal diameters have a greater influence on the gas flow dynamics in terms of a higher reduction in surge margin. The break empirical model for ice crystals and splash model for the droplets that are used to calculate the secondary particle size upon impact with rotor blades have a significant influence on the gas flow predictions. Advisors/Committee Members: Prasad, J. V. R. (advisor), Seitzman, Jerry (committee member), Sankar, Lakshmi (committee member), Jagoda, J. I. (committee member), Singh, Rajkeshar (committee member).

Subjects/Keywords: Engine icing; Compressor; Jet engine; Compressible flow; Compressor stall

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APA (6^th Edition):

Kundu, R. (2015). Impact of engine icing on jet engine compressor flow dynamics. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/54870

Chicago Manual of Style (16^th Edition):

Kundu, Reema. “Impact of engine icing on jet engine compressor flow dynamics.” 2015. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/54870.

MLA Handbook (7^th Edition):

Kundu, Reema. “Impact of engine icing on jet engine compressor flow dynamics.” 2015. Web. 11 Apr 2021.

Vancouver:

Kundu R. Impact of engine icing on jet engine compressor flow dynamics. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/54870.

Council of Science Editors:

Kundu R. Impact of engine icing on jet engine compressor flow dynamics. [Doctoral Dissertation]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/54870

Georgia Tech

13. Caruso, Natalie R. S. Facility effects on Helicon ion thruster operation.

Degree: PhD, Aerospace Engineering, 2016, Georgia Tech

URL: http://hdl.handle.net/1853/55014

► In order to enable comparison of Helicon ion thruster performance across different vacuum test facilities, an understanding of the effect of operating pressure on plasma… (more)

Subjects/Keywords: Helicon ion thruster; MadHeX; Facility effects; Neutral ingestion; Magnetic nozzle; Plasma; Electric propulsion

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APA (6^th Edition):

Caruso, N. R. S. (2016). Facility effects on Helicon ion thruster operation. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/55014

Chicago Manual of Style (16^th Edition):

Caruso, Natalie R S. “Facility effects on Helicon ion thruster operation.” 2016. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/55014.

MLA Handbook (7^th Edition):

Caruso, Natalie R S. “Facility effects on Helicon ion thruster operation.” 2016. Web. 11 Apr 2021.

Vancouver:

Caruso NRS. Facility effects on Helicon ion thruster operation. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/55014.

Council of Science Editors:

Caruso NRS. Facility effects on Helicon ion thruster operation. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/55014

Georgia Tech

14. Smith, Andrew Gerard. Simulations of vitiated bluff body stabilized flames.

Degree: PhD, Aerospace Engineering, 2016, Georgia Tech

URL: http://hdl.handle.net/1853/55582

► Bluff bodies have a wide range of applications where low-cost, light weight methods are needed to stabilize flames in high-speed flow. The principles of bluff… (more)

▼ Bluff bodies have a wide range of applications where low-cost, light weight methods are needed to stabilize flames in high-speed flow. The principles of bluff body flame stabilization are straightforward, but many details are not understood; this is especially true in vitiated environments where measurements are difficult to obtain. Most work has focused on premixed flames but changing application requirements are now driving studies on non-premixed gaseous and spray flames. This thesis aims to improve the understanding of vitiated, bluff body stabilized flames, specifically on non-premixed, spray flames, through the use of Large Eddy Simulation (LES). The single flameholder facility at Georgia Tech was chosen as the basis for the simulations in this thesis. The flameholder was a rectangular bluff body with an aerodynamic leading edge with discrete liquid fuel injectors embedded just upstream of the trailing edge in a configuration described as “close-coupled.” The liquid phase was modeled using a Lagrangian particle approach where discrete fuel droplets were injected into the domain. Experimental data was used to tune model parameters as well as the stripped droplet velocities and sizes. The discharge coefficient needed to be taken into account to achieve the correct fuel jet penetration. The experiments were conducted over a range of global equivalence ratios; lean equivalence ratios, φ global ≈ 0.5, exhibited symmetric flame shedding and conversely large scale sinusoidal B ́ernard/von-K ́arm ́an shedding was observed when the equiva- lence ratio was near unity. Reacting flow LES were computed at these two fuel flow rates to improve understanding of the different flame dynamics. LES were first com- pleted using a quasi-laminar subgrid turbulence-chemistry interaction model. Span- wise averaging of instantaneous and time-averaged LES results were compared with experimental high- and low-speed imaging and showed the LES was in qualitative agreement at both fuel flow rates. At phi_global ≈ 0.5, the fuel jet did not penetrate as far into the crossflow compared to phi_global ≈ 0.95 and thus more fuel was delivered to the shear layers of the bluff body resulting in higher heat release in the shear layers for the low fuel flow rate. The heat release damped the large sinusoidal structures via gas expansion and baroclinic torque generation. Higher fuel jet penetration in the phi_global ≈ 0.95 case meant less fuel was delivered to the shear layers and so less heat release occurred directly behind the bluff body so the large scale sinusoidal shedding was not damped. The impact of the subgrid turbulence-chemistry interaction model on the flame dynamics was tested by comparing the quasi-laminar LES with LES using the subgrid linear eddy model (LEMLES). The flame structure predicted with LEMLES matched that of the quasi-laminar LES, at both fuel flow rates in the near- field behind the bluff body but deviated farther downstream. A flame edge analysis showed little sensitivity to the choice of… Advisors/Committee Members: Menon, Suresh (advisor), Seitzman, Jerry (committee member), Lovett, Jeffery (committee member), Sankar, Lakshmi (committee member), Jagoda, Jechiel (committee member).

Subjects/Keywords: LES; Bluff body; Combustion

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APA (6^th Edition):

Smith, A. G. (2016). Simulations of vitiated bluff body stabilized flames. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/55582

Chicago Manual of Style (16^th Edition):

Smith, Andrew Gerard. “Simulations of vitiated bluff body stabilized flames.” 2016. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/55582.

MLA Handbook (7^th Edition):

Smith, Andrew Gerard. “Simulations of vitiated bluff body stabilized flames.” 2016. Web. 11 Apr 2021.

Vancouver:

Smith AG. Simulations of vitiated bluff body stabilized flames. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/55582.

Council of Science Editors:

Smith AG. Simulations of vitiated bluff body stabilized flames. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/55582

Georgia Tech

15. Fries, Dan. Entrainment, Mixing, and Ignition in Single and Multiple Jets in a Supersonic Crossflow.

Degree: PhD, Aerospace Engineering, 2020, Georgia Tech

URL: http://hdl.handle.net/1853/64095

► Jets in crossflow are a canonical example for three-dimensional turbulent mixing. Here, non-reacting and reacting sonic jets in a supersonic crossflow are studied. The influence… (more)

▼ Jets in crossflow are a canonical example for three-dimensional turbulent mixing. Here, non-reacting and reacting sonic jets in a supersonic crossflow are studied. The influence of injectant properties on turbulent mixing is investigated. Using pure gases, the molecular weight and specific heat ratio is varied between 4-44 g/mol and 1.24-1.66, respectively. The jets are injected into a Mach 1.71 crossflow with a stagnation temperature ~600 K. Two single jet injectors and two staged jet injectors are designed to characterize potential enhancements in turbulent mixing and combustion processes. Mixture fraction and velocity fields are determined via Mie-scattering off solid particles. Velocity vectors are obtained by processing Mie-scattering image pairs with a correlation technique (particle image velocimetry). To ignite the flow field and enable systematic variation of the ignition location a traversable laser spark system is employed. The reacting flow is probed via CH* chemiluminescence and OH planar laser induced fluorescence visualizing regions containing hot combustion products. A new trajectory scaling improves correlation between all data sets considered, suggesting that the bow shock, boundary layer and momentum flux ratio are the dominant controlling factors. Turbulent mixing rates are highest for injectants with higher molecular weight and lower specific heat ratio. The larger of two jet spacings tested yields the greater enhancement of turbulent mixing rates. Ignition locations on the symmetry plane of the flow field are evaluated for their ability to sustain chemical reactions/heat release. Most favorable ignition locations lie in the windward jet shear layer away from the regions of highest flow strain. The smallest diameter single jet with presumably more boundary layer interaction and moderate strain rates provides the best results with regard to thermal energy release after spark deposition. Trends suggest that moderate compressible strain rates and no flow expansion are advantageous to sustain thermal energy release. Implications for future research directions and opportunities are discussed. Advisors/Committee Members: Menon, Suresh (advisor), Ranjan, Devesh (advisor), Steinberg, Adam M (committee member), Seitzman, Jerry M (committee member), Ombrello, Timothy M (committee member).

Subjects/Keywords: Jet in Crossflow; Supersonic Flow; Turbulent mixing; Laser ignition; Staged jets

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APA (6^th Edition):

Fries, D. (2020). Entrainment, Mixing, and Ignition in Single and Multiple Jets in a Supersonic Crossflow. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/64095

Chicago Manual of Style (16^th Edition):

Fries, Dan. “Entrainment, Mixing, and Ignition in Single and Multiple Jets in a Supersonic Crossflow.” 2020. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/64095.

MLA Handbook (7^th Edition):

Fries, Dan. “Entrainment, Mixing, and Ignition in Single and Multiple Jets in a Supersonic Crossflow.” 2020. Web. 11 Apr 2021.

Vancouver:

Fries D. Entrainment, Mixing, and Ignition in Single and Multiple Jets in a Supersonic Crossflow. [Internet] [Doctoral dissertation]. Georgia Tech; 2020. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/64095.

Council of Science Editors:

Fries D. Entrainment, Mixing, and Ignition in Single and Multiple Jets in a Supersonic Crossflow. [Doctoral Dissertation]. Georgia Tech; 2020. Available from: http://hdl.handle.net/1853/64095

16. Magina, Nicholas A. Dynamics of Harmonically Forced Nonpremixed Flames.

Degree: PhD, Aerospace Engineering, 2016, Georgia Tech

URL: http://hdl.handle.net/1853/55559

► This thesis describes the dynamics, both spatio-temporal and heat release, of harmonically excited non-premixed flames. Analytical, numerical, computational, and, experimental analyses were performed, along with… (more)

Subjects/Keywords: Non-premixed flame; Diffusion flame; Linear flame response dynamics; Velocity coupled response; Combustion instabilities; Flame transfer function

11 more images…

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APA (6^th Edition):

Magina, N. A. (2016). Dynamics of Harmonically Forced Nonpremixed Flames. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/55559

Chicago Manual of Style (16^th Edition):

Magina, Nicholas A. “Dynamics of Harmonically Forced Nonpremixed Flames.” 2016. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/55559.

MLA Handbook (7^th Edition):

Magina, Nicholas A. “Dynamics of Harmonically Forced Nonpremixed Flames.” 2016. Web. 11 Apr 2021.

Vancouver:

Magina NA. Dynamics of Harmonically Forced Nonpremixed Flames. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/55559.

Council of Science Editors:

Magina NA. Dynamics of Harmonically Forced Nonpremixed Flames. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/55559

17. Pasumarti, Venkata-Ramya. Large eddy simulation of heated pulsed jets in high speed turbulent crossflow.

Degree: MS, Aerospace Engineering, 2010, Georgia Tech

URL: http://hdl.handle.net/1853/37291

► The jet-in-crossflow problem has been extensively studied, mainly because of its applications in film cooling and injector designs. It has been established that in low-speed… (more)

Subjects/Keywords: LES; Jet in crossflow; Jet scaling; Compressible flow; Turbulent flow; Fluid dynamics; Eddies

11 more images…

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APA (6^th Edition):

Pasumarti, V. (2010). Large eddy simulation of heated pulsed jets in high speed turbulent crossflow. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/37291

Chicago Manual of Style (16^th Edition):

Pasumarti, Venkata-Ramya. “Large eddy simulation of heated pulsed jets in high speed turbulent crossflow.” 2010. Masters Thesis, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/37291.

MLA Handbook (7^th Edition):

Pasumarti, Venkata-Ramya. “Large eddy simulation of heated pulsed jets in high speed turbulent crossflow.” 2010. Web. 11 Apr 2021.

Vancouver:

Pasumarti V. Large eddy simulation of heated pulsed jets in high speed turbulent crossflow. [Internet] [Masters thesis]. Georgia Tech; 2010. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/37291.

Council of Science Editors:

Pasumarti V. Large eddy simulation of heated pulsed jets in high speed turbulent crossflow. [Masters Thesis]. Georgia Tech; 2010. Available from: http://hdl.handle.net/1853/37291

Georgia Tech

18. Syed, Mohmed Akil. High temperature pyrolysis and gasification of biomass and blends.

Degree: PhD, Chemical and Biomolecular Engineering, 2016, Georgia Tech

URL: http://hdl.handle.net/1853/59740

► Biomass is expected to play an important role in the future because biomass can be gasified to produce syngas for the sustainable production of electricity,… (more)

▼ Biomass is expected to play an important role in the future because biomass can be gasified to produce syngas for the sustainable production of electricity, chemicals, and fuels. The research focus of this thesis was to provide a more fundamental understanding of four important parameters that affect biomass char gasification kinetics in a gasifier - pyrolysis conditions, biomass composition and inorganic content, interaction between two biomasses when co-fed together, and the gasifying media. The first study showed that higher pyrolysis temperature and higher residence time in a pressurized entrained flow reactor led to a decrease in char gasification reactivity. Furthermore, a complex char reactivity dependence on pyrolysis pressure is observed with minimum char reactivity at 15 bar (at 800 °C – 26 s – 5 to 20 bar). The second study correlated the reactivity of different types of biomass chars with its active surface area measured by CO2 chemisorption. This empirical correlation can be used for predicting the gasification reactivity of different biomass chars. The third study demonstrated that co-gasification of mixtures of Brazilian bagasse and cane trash was not additive. It was found that co-gasification of these two biomasses led to lower than expected gasification performance due to potassium redistribution between chars. The last study showed that the active sites for steam and CO2 gasification are likely to be the same. However, as the char gasification progresses in pure steam, the active sites are likely to be blocked by in-situ hydrogen product formation. It was demonstrated that product inhibition by hydrogen led to a different gasification reactivity profile in steam compared to CO2 during gasification of potassium containing bagasse char. Advisors/Committee Members: Agrawal, Pradeep K. (advisor), Sievers, Carsten (committee member), Seitzman, Jerry M. (committee member), Muzzy, John D. (committee member), Lively, Ryan P. (committee member), Flick, Derrick W. (committee member).

Subjects/Keywords: Biomass; Pyrolysis; Char gasification; High pressure pyrolysis; Pressurized entrained flow reactor; Sugarcane bagasse; Cane tops and leaves; CO2 gasification; Steam gasification; CO2 chemisorption; Co-gasification

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APA (6^th Edition):

Syed, M. A. (2016). High temperature pyrolysis and gasification of biomass and blends. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/59740

Chicago Manual of Style (16^th Edition):

Syed, Mohmed Akil. “High temperature pyrolysis and gasification of biomass and blends.” 2016. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/59740.

MLA Handbook (7^th Edition):

Syed, Mohmed Akil. “High temperature pyrolysis and gasification of biomass and blends.” 2016. Web. 11 Apr 2021.

Vancouver:

Syed MA. High temperature pyrolysis and gasification of biomass and blends. [Internet] [Doctoral dissertation]. Georgia Tech; 2016. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/59740.

Council of Science Editors:

Syed MA. High temperature pyrolysis and gasification of biomass and blends. [Doctoral Dissertation]. Georgia Tech; 2016. Available from: http://hdl.handle.net/1853/59740

Georgia Tech

19. Newalkar, Gautami. High-pressure pyrolysis and gasification of biomass.

Degree: PhD, Chemical and Biomolecular Engineering, 2015, Georgia Tech

URL: http://hdl.handle.net/1853/53917

► With the limited reserves of fossil fuels and the environmental problems associated with their use, the world is moving towards cleaner, renewable, and sustainable sources… (more)

▼ With the limited reserves of fossil fuels and the environmental problems associated with their use, the world is moving towards cleaner, renewable, and sustainable sources of energy. Biomass is a promising feedstock towards attaining this goal because it is abundant, renewable, and can be considered as a carbon neutral source of energy. Syngas can be further processed to produce liquid fuels, hydrogen, high value chemicals, or it can be converted to heat and power using turbines. Most of the downstream processing of syngas occurs at high pressures, which requires cost intensive gas compression. It has been considered to be techno-economically advantageous to generate pressurized syngas by performing high-pressure gasification. Gasification utilizes high temperatures and an oxidizing gas to convert biomass to synthesis gas (syngas, a mixture of CO and H2). Most of the past studies on gasification used process conditions that did not simulate an industrial gasification operation. This work aims at understanding the chemical and physical transformations taking place during high-pressure biomass gasification at heating rates of practical significance. We have adopted an approach of breaking down the gasification process into two steps: 1) Pyrolysis or devolatalization (fast step), and 2) Char gasification (slow step). This approach allows us to understand pyrolysis and char gasification separately and also to study the effect of pyrolysis conditions on the char gasification kinetics. Alkali and alkaline earth metals in biomass are known to catalyze the gasification reaction. This potentially makes biomass feedstock a cheap source of catalyst during coal gasification. This work also explores catalytic interactions in biomass-coal blends during co-gasification of the mixed feeds. The results of this study can be divided into four parts: (a) pyrolysis of loblolly pine; (b) gasification of pine chars; (c) pyrolysis and gasification of switchgrass; (d) co-gasification of pine/switchgrass with lignite and bituminous coals. Advisors/Committee Members: Sievers, Carsten (advisor), Agrawal, Pradeep K. (advisor), Seitzman, Jerry (committee member), Sinquefield, Scott (committee member), Iisa, Kristiina (committee member), Koros, William J. (committee member).

Subjects/Keywords: Biomass; Pyrolysis; Gasification; Co-gasification; Coal; Renewable energy

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APA (6^th Edition):

Newalkar, G. (2015). High-pressure pyrolysis and gasification of biomass. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/53917

Chicago Manual of Style (16^th Edition):

Newalkar, Gautami. “High-pressure pyrolysis and gasification of biomass.” 2015. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/53917.

MLA Handbook (7^th Edition):

Newalkar, Gautami. “High-pressure pyrolysis and gasification of biomass.” 2015. Web. 11 Apr 2021.

Vancouver:

Newalkar G. High-pressure pyrolysis and gasification of biomass. [Internet] [Doctoral dissertation]. Georgia Tech; 2015. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/53917.

Council of Science Editors:

Newalkar G. High-pressure pyrolysis and gasification of biomass. [Doctoral Dissertation]. Georgia Tech; 2015. Available from: http://hdl.handle.net/1853/53917

20. Periagaram, Karthik Balasubramanian. Determination of flame characteristics in a low swirl burner at gas turbine conditions through reaction zone imaging.

Degree: PhD, Aerospace Engineering, 2012, Georgia Tech

URL: http://hdl.handle.net/1853/45828

► This thesis explores the effects of operating parameters on the location and shape of lifted flames in a Low Swirl Burner (LSB). In addition, it… (more)

▼ This thesis explores the effects of operating parameters on the location and shape of lifted flames in a Low Swirl Burner (LSB). In addition, it details the development and analysis of a CH PLIF imaging system for visualizing flames in lean combustion systems. The LSB is studied at atmospheric pressure using LDV and CH PLIF. CH* chemiluminescence is used for high pressure flame imaging. A four-level model of the fluorescing CH system is developed to predict the signal intensity in hydrocarbon flames. Results from imaging an atmospheric pressure laminar flame are used to validate the behavior of the signal intensity as predicted by the model. The results show that the fluorescence signal is greatly reduced at high pressure due to the decreased number of CH molecules and the increased collisional quenching rate. This restricts the use of this technique to increasingly narrow equivalence ratio ranges at high pressures. The limitation is somewhat alleviated by increasing the preheat temperature of the reactant mixture. The signal levels from high hydrogen-content syngas mixtures doped with methane are found to be high enough to make CH PLIF a feasible diagnostic to study such flames. Finally, the model predicts that signal levels are unlikely to be significantly affected by the presence of strain in the flow field, as long as the flames are not close to extinction. The results from the LSB flame investigation reveal that combustor provides reasonably robust flame stabilization at low and moderate values of combustor pressure and reference velocities. However, at very high velocities and pressures, the balance between the reactant velocity and the turbulent flame speed shifts in favor of the former resulting in the flame moving downstream. The extent of this movement is small, but indicates a tendency towards blow off at higher pressures and velocities that may be encountered in real world gas turbine applications. There is an increased tendency of relatively fuel-rich flames to behave like attached flames at high pressure. These results raise interesting questions about turbulent combustion at high pressure as well as provide usable data to gas turbine combustor designers by highlighting potential problems. Advisors/Committee Members: Seitzman, Jerry (Committee Chair), Genzale, Caroline (Committee Member), Jagoda, Jeff (Committee Member), Lieuwen, Tim (Committee Member), Menon, Suresh (Committee Member).

Subjects/Keywords: Chemkin; LIF modeling; LSB; CH PLIF; Swirl combustor; Combustion engineering; Combustion; Flame stability; Gas-turbines

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APA (6^th Edition):

Periagaram, K. B. (2012). Determination of flame characteristics in a low swirl burner at gas turbine conditions through reaction zone imaging. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/45828

Chicago Manual of Style (16^th Edition):

Periagaram, Karthik Balasubramanian. “Determination of flame characteristics in a low swirl burner at gas turbine conditions through reaction zone imaging.” 2012. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/45828.

MLA Handbook (7^th Edition):

Periagaram, Karthik Balasubramanian. “Determination of flame characteristics in a low swirl burner at gas turbine conditions through reaction zone imaging.” 2012. Web. 11 Apr 2021.

Vancouver:

Periagaram KB. Determination of flame characteristics in a low swirl burner at gas turbine conditions through reaction zone imaging. [Internet] [Doctoral dissertation]. Georgia Tech; 2012. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/45828.

Council of Science Editors:

Periagaram KB. Determination of flame characteristics in a low swirl burner at gas turbine conditions through reaction zone imaging. [Doctoral Dissertation]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/45828

21. Williams, Logan Todd. Ion acceleration mechanisms of helicon thrusters.

Degree: PhD, Aerospace Engineering, 2013, Georgia Tech

URL: http://hdl.handle.net/1853/47691

► A helicon plasma source is a device that can efficiently ionize a gas to create high density, low temperature plasma. There is growing interest in… (more)

▼ A helicon plasma source is a device that can efficiently ionize a gas to create high density, low temperature plasma. There is growing interest in utilizing a helicon plasma source in propulsive applications, but it is not yet known if the helicon plasma source is able to function as both an ion source and ion accelerator, or whether an additional ion acceleration stage is required. In order to evaluate the capability of the helicon source to accelerate ions, the acceleration and ionization processes must be decoupled and examined individually. To accomplish this, a case study of two helicon thruster configurations is conducted. The first is an electrodeless design that consists of the helicon plasma source alone, and the second is a helicon ion engine that combines the helicon plasma source with electrostatic grids used in ion engines. The gridded configuration separates the ionization and ion acceleration mechanisms and allows for individual evaluation not only of ion acceleration, but also of the components of total power expenditure and the ion production cost. In this study, both thruster configurations are fabricated and experimentally characterized. The metrics used to evaluate ion acceleration are ion energy, ion beam current, and the plume divergence half-angle, as these capture the magnitude of ion acceleration and the bulk trajectory of the accelerated ions. The electrode-less thruster is further studied by measuring the plasma potential, ion number density, and electron temperature inside the discharge chamber and in the plume up to 60 cm downstream and 45 cm radially outward. The two configurations are tested across several operating parameter ranges: 343-600 W RF power, 50-450 G magnetic field strength, 1.0-4.5 mg/s argon flow rate, and the gridded configuration is tested over a 100-600 V discharge voltage range. Both configurations have thrust and efficiency below that of contemporary thrusters of similar power, but are distinct in terms of ion acceleration capability. The gridded configuration produces a 65-120 mA ion beam with energies in the hundreds of volts that is relatively collimated. The operating conditions also demonstrate clear control over the performance metrics. In contrast, the electrodeless configuration generally produces a beam current less than 20 mA at energies between 20-40 V in a very divergent plume. The ion energy is set by the change in plasma potential from inside the device to the plume. The divergence ion trajectories are caused by regions of high plasma potential that create radial electric fields.. Furthermore, the operating conditions have limited control of the resulting performance metrics. The estimated ion production cost of the helicon ranged between 132-212 eV/ion for argon, the lower bound of which is comparable to the 157 eV/ion in contemporary DC discharges. The primary power expenditures are due to ion loss to the walls and high electron temperature leading to energy loss at the plasma sheaths. The conclusion from this work is that the… Advisors/Committee Members: Walker, Mitchell (Committee Chair), Jagoda, Jechiel (Committee Member), Longmier, Benjamin (Committee Member), Seitzman, Jerry (Committee Member), Wilhite, Alan (Committee Member).

Subjects/Keywords: Ion acceleration; Ion engine; Helicon; Ion accelerators; Particle accelerators; Propulsion systems; Helicons (Electromagnetism)

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APA (6^th Edition):

Williams, L. T. (2013). Ion acceleration mechanisms of helicon thrusters. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/47691

Chicago Manual of Style (16^th Edition):

Williams, Logan Todd. “Ion acceleration mechanisms of helicon thrusters.” 2013. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/47691.

MLA Handbook (7^th Edition):

Williams, Logan Todd. “Ion acceleration mechanisms of helicon thrusters.” 2013. Web. 11 Apr 2021.

Vancouver:

Williams LT. Ion acceleration mechanisms of helicon thrusters. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/47691.

Council of Science Editors:

Williams LT. Ion acceleration mechanisms of helicon thrusters. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/47691

22. Singh, Lake Austin. Very low earth orbit propellant collection feasibility assessment.

Degree: PhD, Aerospace Engineering, 2014, Georgia Tech

URL: http://hdl.handle.net/1853/53039

► This work focuses on the concept of sustainable propellant collection. The concept consists of gathering ambient gas while on-orbit and using it as propellant. Propellant… (more)

Subjects/Keywords: Propellant collection; Electric propulsion; Air-breathing propulsion

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APA (6^th Edition):

Singh, L. A. (2014). Very low earth orbit propellant collection feasibility assessment. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/53039

Chicago Manual of Style (16^th Edition):

Singh, Lake Austin. “Very low earth orbit propellant collection feasibility assessment.” 2014. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/53039.

MLA Handbook (7^th Edition):

Singh, Lake Austin. “Very low earth orbit propellant collection feasibility assessment.” 2014. Web. 11 Apr 2021.

Vancouver:

Singh LA. Very low earth orbit propellant collection feasibility assessment. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/53039.

Council of Science Editors:

Singh LA. Very low earth orbit propellant collection feasibility assessment. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/53039

23. Kim, Jaecheol. The role of radicals supplied directly and indirectly on ignition.

Degree: PhD, Aerospace Engineering, 2014, Georgia Tech

URL: http://hdl.handle.net/1853/53001

► The ignition process is a critical consideration for combustion devices. External energy transfer to the combustor is required for ignition in common combustion systems. There… (more)

▼ The ignition process is a critical consideration for combustion devices. External energy transfer to the combustor is required for ignition in common combustion systems. There are many ways to deposit energy into the flow but a standard method is a spark discharge because it is simple, compact, and reliable. Sparks can be categorized as either inductive or capacitive sparks that use a coil or an electrical resonance circuit with capacitor, respectively, to amplify the voltage. The creation of a successful ignition event depends on the spark energy deposited into the flow, the initial composition, pressure, temperature, turbulence level of flow etc. The deposited energy by the spark into the flow is critical for estimation of initial energy available for ignition of the mixture. Therefore, the electrical characteristics of the sparks were investigated under various flow conditions. Then measurements of deposited energy into the flow were conducted using a very accurate experimental procedure that was developed in this research. The results showed considerable electric energy losses to the electrodes for the relatively long, inductive sparks. However, the short, capacitive spark deposits electric energy into the flow with minimal loss (above 90% deposition efficiency). In addition, the characteristics of inductive spark are affected by flow velocity and by the existence of a flame. However, variations in the flow conditions do not affect the characteristics of the capacitive spark such as voltage-current time trace and energy deposition efficiency. Two ignition systems using above mentioned two spark types were developed. First, the capacitive spark energy was directly deposited into the premixed flow. Most researchers have not concentrated on the early initiation process but on the flame growth. Therefore, the generated kernel formed by the energy deposition was observed and characterized using optical methods, immediately following the spark. In addition, the mixing effect for this ignition kernel with surrounding gas was simulated using a numerical method. Based on the time trace of the OH* chemiluminescence, the reaction starts with the discharge and it is continuous until combustion begins. This means that in the presence of a high density spark in premixed flow, there exists no traditional delay as defined by other researchers for auto ignition. A simple Radical Jet Generator (RJG) was developed that is able to ignite and stabilize a flame in a high-speed flow. The inductive spark initiates the combustion in the RJG chamber. The RJG then injects the partially-burned products carrying large amounts of heat and radicals into a rapidly moving flammable main stream. Then it ignites and stabilizes a flame. The RJG requires low levels of electrical power as long as the flow velocity is relatively low since most of the radicals are produced by the incomplete combustion in its chamber. The importance of radicals was analyzed by RJG experiments and numerical methods. The reaction zone for RJG using a rich mixture was… Advisors/Committee Members: Jagoda, Jeff (advisor), Seitzman, Jerry (committee member), Scarborough, David (committee member), Menon, Suresh (committee member), Choi, Woong-sik (committee member).

Subjects/Keywords: High energy; OH chemiluminescence;

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APA (6^th Edition):

Kim, J. (2014). The role of radicals supplied directly and indirectly on ignition. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/53001

Chicago Manual of Style (16^th Edition):

Kim, Jaecheol. “The role of radicals supplied directly and indirectly on ignition.” 2014. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/53001.

MLA Handbook (7^th Edition):

Kim, Jaecheol. “The role of radicals supplied directly and indirectly on ignition.” 2014. Web. 11 Apr 2021.

Vancouver:

Kim J. The role of radicals supplied directly and indirectly on ignition. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/53001.

Council of Science Editors:

Kim J. The role of radicals supplied directly and indirectly on ignition. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/53001

24. Sforzo, Brandon Anthony. High energy spark ignition in non-premixed flowing combustors.

Degree: PhD, Aerospace Engineering, 2014, Georgia Tech

URL: http://hdl.handle.net/1853/53014

► In many practical combustion devices, including those used in gas turbine engines for aircraft and power generation, a high energy spark kernel is necessary to… (more)

▼ In many practical combustion devices, including those used in gas turbine engines for aircraft and power generation, a high energy spark kernel is necessary to reliably ignite the turbulently flowing flammable gases. Complicating matters, the spark kernel is sometimes generated in a region where a non-flammable mixture is present, or where there is no fuel at all. This requires the spark kernel to travel to a flammable region before rapid combustion can begin in non-premixed or stratified flows. This transit time allows for chemical reactions to take place within the kernel as well as mixing with surrounding gases. Despite these demanding conditions, the majority of research in ignition has been for low energy sparks and premixed conditions, not resembling those found in many combustion devices. Similarly, there is little work addressing this issue of spark kernel evolution in the non-premixed flowing environment, and none available that control the time allowed for transit. The goal of this thesis is to understand the development of a spark kernel issued into a non-premixed flow and the sensitivities of the ignition process. To this effect, a stratified flow facility for ignition experiments has been fabricated utilizing a high speed schlieren and emission imaging system for visualizing the kernel motion and ignition success. Additionally, OH chemiluminescence and CH PLIF were used to track chemical species during the ignition process. This facility is also used to control the important variables regarding the flow and spark kernel interaction to quantify the influence on ignition probability. A reduced order model employing a perfectly stirred reactor (PSR) has also been developed based on experimental observations of the entrainment of fluid into the evolving kernel. The simulations provide additional insight to the chemical development in the kernel under different input conditions. This model was enhanced by introducing random perturbations to the input variables, mimicking a practical situation. A computationally efficient support vector machine was trained to replicate the numerical model outputs and predict ignition probabilities for nominal input conditions, providing comparison to experimental results. Experimental and numerical results show that initial mixing with non-flammable fluid quickly reduces the ability for the kernel to ignite the flammable flow, resulting in a strong influence of the inlet temperature and the kernel transit time on the probability of ignition. Once the kernel reaches the flammable mixture, entrainment of this flow occurs, which requires on the order of a vortex turn-over time before chemistry can begin. Initial chemical reactions include endothermic fuel decomposition, further reducing the kernel temperature prior to heat release, creating a competition between the cooling effect of additional mass entrainment and the delayed heat release reactions. CH PLIF results show that flame chemistry is initially confined to a thin region that corresponds to the… Advisors/Committee Members: Seitzman, Jerry (advisor), Jagoda, Jeff (committee member), Menon, Suresh (committee member), Sun, Wenting (committee member), McKinney, Randal (committee member).

Subjects/Keywords: Ignition; Combustion; Experimental; Numerical; Gas turbines

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APA (6^th Edition):

Sforzo, B. A. (2014). High energy spark ignition in non-premixed flowing combustors. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/53014

Chicago Manual of Style (16^th Edition):

Sforzo, Brandon Anthony. “High energy spark ignition in non-premixed flowing combustors.” 2014. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/53014.

MLA Handbook (7^th Edition):

Sforzo, Brandon Anthony. “High energy spark ignition in non-premixed flowing combustors.” 2014. Web. 11 Apr 2021.

Vancouver:

Sforzo BA. High energy spark ignition in non-premixed flowing combustors. [Internet] [Doctoral dissertation]. Georgia Tech; 2014. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/53014.

Council of Science Editors:

Sforzo BA. High energy spark ignition in non-premixed flowing combustors. [Doctoral Dissertation]. Georgia Tech; 2014. Available from: http://hdl.handle.net/1853/53014

25. Gopala, Yogish. Breakup characteristics of a liquid jet in subsonic crossflow.

Degree: PhD, Aerospace Engineering, 2012, Georgia Tech

URL: http://hdl.handle.net/1853/44741

► This thesis describes an experimental investigation of the breakup processes involved in the formation of a spray created by a liquid jet injected into a… (more)

▼ This thesis describes an experimental investigation of the breakup processes involved in the formation of a spray created by a liquid jet injected into a gaseous crossflow. This work is motivated by the utilization of this method to inject fuel in combustors and afterburners of airplane engines. This study aims to develop better understanding of the spray breakup processes and provide better experimental inputs to improve the fidelity of numerical models. This work adresses two key research areas: determining the time required for a liquid column to break up in the crossflow (i.e., primary breakup time) and the effect of injector geometry on spray properties. A new diagnostic technique, the liquid jet light guiding technique that utilizes ability of the liquid jet to act as a waveguide for laser light was developed to determine the location where the liquid column breaks up, in order to obtain the primary breakup time. This study found that the liquid jet Reynolds number was an important factor that governed the primary breakup time and improved the existing correlation. Optical diagnostic techniques such as Phase Doppler Particle Analyzer, Liquid Jet Light Guiding Technique, Particle Image Velocimetry and Imaging techniques were employed to measure the spray properties that include spray penetration, droplet sizes and velocities, velocity field on the surface of the liquid jet and the location of the primary breakup time. These properties were measured for two injectors: one with a sharp transition and the other with a smooth transition. It was found that the spray created by the injector with a sharp transition forms large irregular structures while one with smooth transition produces a smooth liquid jet. The spray transition creates a spray that penetrates deeper into the crossflow, breakup up earlier and produces larger droplets. Additionally, this study reports the phenomenon of the liquid jet splitting into two or more jets in sprays created by the injector with a smooth transition. Advisors/Committee Members: Zinn, Ben (Committee Chair), Genzale, Caroline (Committee Member), Lubarsky, Eugene (Committee Member), Menon, Suresh (Committee Member), Seitzman, Jerry (Committee Member).

Subjects/Keywords: Sharp edged orifice; Primary breakup; Column breakup point; Jet in crossflow; Round edged orifice; Airplanes Motors; Reynolds number; Fluid mechanics

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APA (6^th Edition):

Gopala, Y. (2012). Breakup characteristics of a liquid jet in subsonic crossflow. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/44741

Chicago Manual of Style (16^th Edition):

Gopala, Yogish. “Breakup characteristics of a liquid jet in subsonic crossflow.” 2012. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/44741.

MLA Handbook (7^th Edition):

Gopala, Yogish. “Breakup characteristics of a liquid jet in subsonic crossflow.” 2012. Web. 11 Apr 2021.

Vancouver:

Gopala Y. Breakup characteristics of a liquid jet in subsonic crossflow. [Internet] [Doctoral dissertation]. Georgia Tech; 2012. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/44741.

Council of Science Editors:

Gopala Y. Breakup characteristics of a liquid jet in subsonic crossflow. [Doctoral Dissertation]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/44741

26. Korzun, Ashley Marie. Aerodynamic and performance characterization of supersonic retropropulsion for application to planetary entry and descent.

Degree: PhD, Aerospace Engineering, 2012, Georgia Tech

URL: http://hdl.handle.net/1853/43667

► Supersonic deceleration has been identified as a critical deficiency in extending heritage technologies to the high-mass systems required to achieve long-term exploration goals at Mars.… (more)

Subjects/Keywords: EDL; Planetary entry; Mars exploration; Retropropulsion; Opposing jets; Aerodynamics; Space vehicles Atmospheric entry; Space vehicles Atmospheric entry Mars (Planet); Aeronautics; Mars (Planet) Aeronautics

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APA (6^th Edition):

Korzun, A. M. (2012). Aerodynamic and performance characterization of supersonic retropropulsion for application to planetary entry and descent. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/43667

Chicago Manual of Style (16^th Edition):

Korzun, Ashley Marie. “Aerodynamic and performance characterization of supersonic retropropulsion for application to planetary entry and descent.” 2012. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/43667.

MLA Handbook (7^th Edition):

Korzun, Ashley Marie. “Aerodynamic and performance characterization of supersonic retropropulsion for application to planetary entry and descent.” 2012. Web. 11 Apr 2021.

Vancouver:

Korzun AM. Aerodynamic and performance characterization of supersonic retropropulsion for application to planetary entry and descent. [Internet] [Doctoral dissertation]. Georgia Tech; 2012. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/43667.

Council of Science Editors:

Korzun AM. Aerodynamic and performance characterization of supersonic retropropulsion for application to planetary entry and descent. [Doctoral Dissertation]. Georgia Tech; 2012. Available from: http://hdl.handle.net/1853/43667

27. Genin, Franklin Marie. Study of compressible turbulent flows in supersonic environment by large-eddy simulation.

Degree: PhD, Aerospace Engineering, 2009, Georgia Tech

URL: http://hdl.handle.net/1853/28085

► A Large-Eddy Simulation (LES) methodology adapted to the resolution of high Reynolds number turbulent flows in supersonic conditions was proposed and developed. A novel numerical… (more)

Subjects/Keywords: Hybrid numerical scheme; Compressible turbulence; LDKM closure; Eddies; Computer simulation; Combustion; Turbulence

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APA (6^th Edition):

Genin, F. M. (2009). Study of compressible turbulent flows in supersonic environment by large-eddy simulation. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/28085

Chicago Manual of Style (16^th Edition):

Genin, Franklin Marie. “Study of compressible turbulent flows in supersonic environment by large-eddy simulation.” 2009. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/28085.

MLA Handbook (7^th Edition):

Genin, Franklin Marie. “Study of compressible turbulent flows in supersonic environment by large-eddy simulation.” 2009. Web. 11 Apr 2021.

Vancouver:

Genin FM. Study of compressible turbulent flows in supersonic environment by large-eddy simulation. [Internet] [Doctoral dissertation]. Georgia Tech; 2009. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/28085.

Council of Science Editors:

Genin FM. Study of compressible turbulent flows in supersonic environment by large-eddy simulation. [Doctoral Dissertation]. Georgia Tech; 2009. Available from: http://hdl.handle.net/1853/28085

28. Sundaram, Dilip Srinivas. Multi-scale modeling of thermochemical behavior of nano-energetic materials.

Degree: PhD, Aerospace Engineering, 2013, Georgia Tech

URL: http://hdl.handle.net/1853/50225

► Conventional energetic materials which are based on monomolecular compounds such as trinitrotoluene (TNT) have relatively low volumetric energy density. The energy density can be significantly… (more)

▼ Conventional energetic materials which are based on monomolecular compounds such as trinitrotoluene (TNT) have relatively low volumetric energy density. The energy density can be significantly enhanced by the addition of metal particulates. Among all metals, aluminum is popular because of its high oxidation enthalpy, low cost, and relative safety. Micron-sized aluminum particles, which have relatively high ignition temperatures and burning times, have been most commonly employed. Ignition of micron-sized aluminum particles is typically achieved only upon melting of the oxide shell at 2350 K, thereby resulting in fairly high ignition delay. Novel approaches to reduce the ignition temperatures and burning times and enhance the energy content of the particle are necessary. Recently, there has been an enormous interest in nano-materials due to their unique physicochemical properties such as lower melting and ignition temperatures and shorter burning times. Favorably, tremendous developments in the synthesis technology of nano-materials have also been made in the recent past. Several metal-based energetic materials with nano-sized particles such as nano-thermites, nano-fluids, and metalized solid propellants are being actively studied. The “green” reactive mixture of nano-aluminum particles and water/ice mixture (ALICE) is being explored for various applications such as space and underwater propulsion, hydrogen generation, and fuel-cell technology. Strand burning experiments indicate that the burning rates of nano-aluminum and water mixtures surpass those of common energetic materials such as ammonium dinitramide (ADN), hydrazinium nitroformate (HNF), and cyclotetramethylene tetranitramine (HMX). Sufficient understanding of key physicochemical phenomena is, however, not present. Furthermore, the most critical parameters that dictate the burning rate have not been identified. A multi-zone theoretical framework is established to predict the burning properties and flame structure by solving conservation equations in each zone and enforcing the mass and energy continuities at the interfacial boundaries. An analytical expression for the burning rate is derived and physicochemical parameters that dictate the flame behavior are identified. An attempt is made to elucidate the rate-controlling combustion mechanism. The effect of bi-modal particle size distribution on the burning rate and flame structure are investigated. The results are compared with the experimental data and favorable agreement is achieved. The ignition and combustion characteristics of micron-sized aluminum particles can also be enhanced by replacing the inert alumina layer with favorable metallic coatings such as nickel. Experiments indicate that nickel-coated aluminum particles ignite at temperatures significantly lower than the melting point of the oxide film, 2350 K due to the presence of inter-metallic reactions. Nickel coating is also attractive for nano-sized aluminum particles due to its ability to maximize the active aluminum content. Understanding… Advisors/Committee Members: Yang, Vigor (advisor), Seitzman, Jerry (committee member), Lieuwen, Timothy (committee member), Jagoda, Jechiel (committee member), Yetter, Richard (committee member).

Subjects/Keywords: Aluminum; Nano-particle; Molecular dynamics; Energetic materials; Nanostructured materials; Nanocomposites (Materials); Thermodynamics; Propellants; Combustion

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APA (6^th Edition):

Sundaram, D. S. (2013). Multi-scale modeling of thermochemical behavior of nano-energetic materials. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/50225

Chicago Manual of Style (16^th Edition):

Sundaram, Dilip Srinivas. “Multi-scale modeling of thermochemical behavior of nano-energetic materials.” 2013. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/50225.

MLA Handbook (7^th Edition):

Sundaram, Dilip Srinivas. “Multi-scale modeling of thermochemical behavior of nano-energetic materials.” 2013. Web. 11 Apr 2021.

Vancouver:

Sundaram DS. Multi-scale modeling of thermochemical behavior of nano-energetic materials. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/50225.

Council of Science Editors:

Sundaram DS. Multi-scale modeling of thermochemical behavior of nano-energetic materials. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/50225

29. Emerson, Benjamin L. Dynamical characteristics of reacting bluff body wakes.

Degree: PhD, Aerospace Engineering, 2013, Georgia Tech

URL: http://hdl.handle.net/1853/49073

► Combustion instability plagues the combustion community in a wide range of applications. This un-solved problem is especially prevalent and expensive in aerospace propulsion and ground… (more)

▼ Combustion instability plagues the combustion community in a wide range of applications. This un-solved problem is especially prevalent and expensive in aerospace propulsion and ground power generation. The challenges associated with understanding and predicting combustion instability lie in the flame response to the acoustic field. One of the more complicated flame response mechanisms is the velocity coupled flame response, where the flame responds dynamically to the acoustic velocity as well as the vortically induced velocity field excited by the acoustics. This vortically induced, or hydrodynamic, velocity field holds critical importance to the flame response but is computationally expensive to predict, often requiring high fidelity CFD computations. Furthermore, its behavior can be a strong function of the numerous flow parameters that change over the operability map of a combustor. This research focuses on a nominally two dimensional bluff body combustor, which has rich hydrodynamic stability behavior with a manageable number of stability parameters. The work focuses first on experimentally characterizing the dynamical flow and flame behavior. Next, the research shifts focus toward hydrodynamic stability theory, using it to explain the physical phenomena observed in the experimental work. Additionally, the hydrodynamic stability work shows how the use of simple, model analysis can identify the important stability parameters and elucidate their governing physical roles. Finally, the research explores the forced response of the flow and flame while systematically varying the underlying hydrodynamic stability characteristics. In the case of longitudinal combustion instability of highly preheated bluff body combustors, it shows that conditions where an acoustic mode frequency equals the hydrodynamic global mode frequency are not especially dangerous from a combustion instability standpoint, and may actually have a reduced heat release response. This demonstrates the very non-intuitive role that the natural hydrodynamic flow stability plays in the forced heat release response of the flame. For the fluid mechanics community, this work contributes to the detailed understanding of both unforced and forced bluff body combustor dynamics, and shows how each is influenced by the underlying hydrodynamics. In particular, it emphasizes the role of the density-shear layer offset, and shows how its extreme sensitivity leads to complicated flow dynamics. For the flow-combustor community as a whole, the work reviews a pre-existing method to obtain the important flow stability parameters, and demonstrates a novel way to link those parameters to the governing flow physics. For the combustion instability community, this thesis emphasizes the importance of the hydrodynamic stability characteristics of the flow, and concludes by offering a paradigm for consideration of the hydrodynamics in a combustion instability problem. Advisors/Committee Members: Lieuwen, Timothy C. (advisor), Seitzman, Jerry (committee member), Menon, Suresh (committee member), Jagoda, Jechiel (committee member), Glezer, Ari (committee member).

Subjects/Keywords: Combustion; Bluff body; Hydrodynamics; Combustion instability; Thermoacoustics; Wakes (Fluid dynamics); Aerodynamics; Combustion Stability; Flame; Hydrodyamics

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

APA (6^th Edition):

Emerson, B. L. (2013). Dynamical characteristics of reacting bluff body wakes. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/49073

Chicago Manual of Style (16^th Edition):

Emerson, Benjamin L. “Dynamical characteristics of reacting bluff body wakes.” 2013. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/49073.

MLA Handbook (7^th Edition):

Emerson, Benjamin L. “Dynamical characteristics of reacting bluff body wakes.” 2013. Web. 11 Apr 2021.

Vancouver:

Emerson BL. Dynamical characteristics of reacting bluff body wakes. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/49073.

Council of Science Editors:

Emerson BL. Dynamical characteristics of reacting bluff body wakes. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/49073

30. Radhakrishnan, Arun. Self-sustained combustion of low grade solid fuels in a stagnation-point reverse-flow combustor.

Degree: PhD, Aerospace Engineering, 2013, Georgia Tech

URL: http://hdl.handle.net/1853/50275

► This thesis investigates the use of the Stagnation-Point Reverse-Flow (SPRF) combustor geometry for burning low-grade solid fuels that are attractive for specific industrial applications because… (more)

▼ This thesis investigates the use of the Stagnation-Point Reverse-Flow (SPRF) combustor geometry for burning low-grade solid fuels that are attractive for specific industrial applications because of their low cost and on-site availability. These fuels are in general, hard to burn, either because of high moisture and impurity-content, e.g. biomass, or their low-volatiles content, e.g., petroleum-coke. This results in various challenges to the combustor designer, for example reduced flame stability and poor combustion efficiency. Conventional solutions include preheating the incoming flow as well as co-firing with high-grade fuels. The SPRF combustor geometry has been chosen because it was demonstrated to operate stably on standard gaseous and liquid-fuels corresponding to ultra fuel-lean conditions and power densities at atmospheric-pressure around 20-25 MW/m3. Previous studies on the SPRF combustor have proven that the unique, reverse flow-geometry allows entrainment of near-adiabatic products into the incoming reactants, thereby enhancing the reactivity of the mixture. Further, the presence of the stagnation-end created a region of low mean velocities and high levels of unsteadiness and mixing-rates that supported the reaction-zones. In this study, we examine the performance of the SPRF geometry on a specific low grade solid fuel, petroleum coke. There are three main goals of this thesis. The first goal is the design of a SPRF combustor to operate on solid-fuels based on a design-scaling methodology, as well as demonstration of successful operation corresponding to a baseline condition. The second goal involves understanding the mode of operation of the SPRF combustor on solid-fuels based on visualization studies. The third goal of this thesis is developing and using reduced-order models to better understand and predict the ignition and quasi-steady burning behavior of dispersed-phase particles in the SPRF combustor. The SPRF combustor has been demonstrated to operate stably on pure-oxygen and a slurry made from water and petroleum-coke, both at the baseline conditions (125 kW, 18 g/s, ~25 µm particles) and higher power-densities and powder sizes. For an overall combustor length less than a meter, combustion is not complete (global combustion efficiency less than 70%). Luminance imaging results indicate the incoming reactant jet ignites and exhibits intense burning at the mid-combustor region, around 15 jet diameters downstream of the inlet, most likely due to enhanced mixing as a result of the highly unsteady velocity field. This roughly corresponds to the location of the reaction zones in the previous SPRF combustors operating on gas and liquid fuels. Planar laser visualization of the reacting flow-field using particle-scattering reveals that ignition of a significant amount of the reactants occurs only after the incoming jet has broken into reactant packets. Post-ignition, these burning packets burn out slowly as they reverse direction and exit the combustor on either side of the central injector. This is… Advisors/Committee Members: Seitzman, Jerry (advisor), Sievers, Carsten (committee member), Jagoda, Jeff (committee member), Zinn, Ben T. (committee member), Lieuwen, Timothy (committee member).

Subjects/Keywords: Petroleum-coke; Solid fuels; Combustion; Combustor; SPRF; Low-grade fuel; Combustion Research; Fuel Combustion; Combustion chambers

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

APA (6^th Edition):

Radhakrishnan, A. (2013). Self-sustained combustion of low grade solid fuels in a stagnation-point reverse-flow combustor. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/50275

Chicago Manual of Style (16^th Edition):

Radhakrishnan, Arun. “Self-sustained combustion of low grade solid fuels in a stagnation-point reverse-flow combustor.” 2013. Doctoral Dissertation, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/50275.

MLA Handbook (7^th Edition):

Radhakrishnan, Arun. “Self-sustained combustion of low grade solid fuels in a stagnation-point reverse-flow combustor.” 2013. Web. 11 Apr 2021.

Vancouver:

Radhakrishnan A. Self-sustained combustion of low grade solid fuels in a stagnation-point reverse-flow combustor. [Internet] [Doctoral dissertation]. Georgia Tech; 2013. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/50275.

Council of Science Editors:

Radhakrishnan A. Self-sustained combustion of low grade solid fuels in a stagnation-point reverse-flow combustor. [Doctoral Dissertation]. Georgia Tech; 2013. Available from: http://hdl.handle.net/1853/50275

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