+publisher:"University of Michigan" +contributor:("Im, Hong G.")

1. Mansfield, Andrew Benjamin. Experimental Study of Synthesis Gas Combustion Chemistry and Ignition Behaviors.

Degree: PhD, Mechanical Engineering, 2014, University of Michigan

URL: http://hdl.handle.net/2027.42/110478

► The development of synthesis gas (syngas) fuel is of interest, as it can enable a transition from fossil to renewable energy sources while reducing the… (more)

▼ The development of synthesis gas (syngas) fuel is of interest, as it can enable a transition from fossil to renewable energy sources while reducing the emissions associated with both. Historical research has focused on basic syngas formulations (H2 & CO) in homogeneous environments, providing a baseline for consideration of more realistic mixtures and devices. Recent research and industrial experience for syngas fueled combustors indicate the effects of common disturbances can be dramatic and are not well-understood, with particular concern regarding the occurrence of uncontrolled inhomogeneous auto-ignition and its effect on the accuracy of common homogeneous reactor modeling. This dissertation represents an experimental investigation of syngas combustion, aimed at comprehensively understanding the effects of specific chemical and physical disturbances at high-pressure low-temperature conditions. Experiments were conducted in the University of Michigan-Rapid Compression Facility. The auto-ignition behaviors of syngas were investigated, revealing the existence of both homogeneous and inhomogeneous characteristics depending strongly on the initial unburned thermodynamic state. The behaviors were mapped over a wide range of conditions revealing consistent patterns. It was discovered that the Sankaran Criterion, a previously proposed relationship between chemical kinetics, transport properties, and known thermal disturbances, could predict the location of inhomogeneous behavior on these maps with remarkable accuracy. This provides evidence that commonly ignored thermal disturbances can cause uncontrolled inhomogeneous auto-ignition in syngas and also provides a straightforward method to predict such behavior. As expected, inhomogeneous auto-ignition behavior was well correlated to error in homogeneous reactor modeling for higher energy content mixtures. The effects of chemical impurities on the combustion of syngas were investigated, focusing on CH4, a common component of syngas, and trimethylsilanol (TMS), an unstudied impurity related to those common to landfill-based syngas. The impact of CH4 was to inhibit ignition, evidenced by auto-ignition delay time increases by up to a factor of 3. Conversely the impact of TMS was to promote ignition, causing drastic reductions in auto-ignition delay time up to 70%. These large promotion effects have significant safety implications, as pronounced early auto-ignition can lead to catastrophic failures and concentrations of similar Si containing species are expected to increase in the future. Advisors/Committee Members: Wooldridge, Margaret S. (committee member), Driscoll, James F. (committee member), Borgnakke, Claus (committee member), Im, Hong G. (committee member).

Subjects/Keywords: Syngas; Iso-octane; Rapid compression facility; Strong and weak ignition; Impurity; Trimethylsilanol; Mechanical Engineering; Engineering

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APA (6^th Edition):

Mansfield, A. B. (2014). Experimental Study of Synthesis Gas Combustion Chemistry and Ignition Behaviors. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/110478

Chicago Manual of Style (16^th Edition):

Mansfield, Andrew Benjamin. “Experimental Study of Synthesis Gas Combustion Chemistry and Ignition Behaviors.” 2014. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/110478.

MLA Handbook (7^th Edition):

Mansfield, Andrew Benjamin. “Experimental Study of Synthesis Gas Combustion Chemistry and Ignition Behaviors.” 2014. Web. 11 Apr 2021.

Vancouver:

Mansfield AB. Experimental Study of Synthesis Gas Combustion Chemistry and Ignition Behaviors. [Internet] [Doctoral dissertation]. University of Michigan; 2014. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/110478.

Council of Science Editors:

Mansfield AB. Experimental Study of Synthesis Gas Combustion Chemistry and Ignition Behaviors. [Doctoral Dissertation]. University of Michigan; 2014. Available from: http://hdl.handle.net/2027.42/110478

University of Michigan

2. Pal, Pinaki. Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications.

Degree: PhD, Mechanical Engineering, 2016, University of Michigan

URL: http://hdl.handle.net/2027.42/120735

► To achieve cleaner and more efficient energy utilization, novel strategies in modern combustion devices operate using lean, premixed reactant mixtures at high pressures. Under these… (more)

▼ To achieve cleaner and more efficient energy utilization, novel strategies in modern combustion devices operate using lean, premixed reactant mixtures at high pressures. Under these conditions, auto-ignition often becomes a dominant process for burning. Therefore, accurate prediction of auto-ignition characteristics is of paramount importance in successful implementation of these advanced combustion systems. The first part of this dissertation focuses on auto-ignition characteristics at high-pressure, low-temperature conditions, relevant to modern gas turbine engines. In particular, strong (homogeneous) and weak (deflagration-dominant) ignition regimes in the presence of thermal inhomogeneities are computationally investigated. Predictive criteria based on Zel’dovich’s theory and passive scalar mixing, which can capture the ignition behavior a priori, are proposed and validated using extensive parametric tests of one-dimensional laminar systems of a lean syngas/air mixture. Subsequently, a non-dimensional scaling analysis is performed to derive regime criteria for turbulent reacting flows, leading to a turbulent ignition regime diagram. The regime diagram is then numerically validated against two-dimensional direct numerical simulations of syngas/air auto-ignition. A number of parametric test cases, by varying the turbulent Damköhler and Reynolds numbers, are considered. The auto-ignition phenomena are characterized by analyzing the corresponding heat release rates and resultant combustion modes. It is demonstrated that the observed ignition behaviors are consistent with the regime diagram predictions. In the second part of the dissertation, applicability of a Reynolds-Averaged Navier Stokes based spray-interactive flamelet (SIF) combustion model to stratified LTC in direct-injection compression ignition (DICI) engines is assessed, which incorporates the interaction between spray evaporation, gas-phase combustion and turbulent mixing. A number of parametric cases are considered by way of varying the fuel start-of-injection (SOI) timing. The numerical results are validated against available experimental data for in-cylinder pressure trace and CO/NO emissions. It is shown that the SIF model performs well over a wide range of stratified conditions due to the incorporation of the effects of small-scale turbulent transport on combustion. Finally, the SIF model is employed to further investigate the impact of fuel injection parameters such as injection pressure and spray cone angle on the NO-CO trade-off of the DICI engine for the most delayed SOI timing. Advisors/Committee Members: Im, Hong G (committee member), Wooldridge, Margaret S (committee member), Raman, Venkatramanan (committee member), Katopodes, Nikolaos D (committee member), Atreya, Arvind (committee member).

Subjects/Keywords: Combustion; Computational fluid dynamics; Modeling and simulation; Turbulence-chemistry interaction; Auto-ignition; High-efficiency engines; Mechanical Engineering; Engineering

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APA (6^th Edition):

Pal, P. (2016). Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/120735

Chicago Manual of Style (16^th Edition):

Pal, Pinaki. “Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications.” 2016. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/120735.

MLA Handbook (7^th Edition):

Pal, Pinaki. “Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications.” 2016. Web. 11 Apr 2021.

Vancouver:

Pal P. Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications. [Internet] [Doctoral dissertation]. University of Michigan; 2016. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/120735.

Council of Science Editors:

Pal P. Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications. [Doctoral Dissertation]. University of Michigan; 2016. Available from: http://hdl.handle.net/2027.42/120735

University of Michigan

3. Lin, Kuang Chuan. Numerical Simulations of Thermal Systems-Applications To Fuel Chemistry, Nanofluid Heat Transfer And Aerosol Particle Transport.

Degree: PhD, Mechanical Engineering, 2011, University of Michigan

URL: http://hdl.handle.net/2027.42/86287

► In this dissertation, three topics in thermal systems are investigated: 1) the effect of methyl-ester content on combustion chemistry of a biodiesel surrogate; 2) the… (more)

▼ In this dissertation, three topics in thermal systems are investigated: 1) the effect of methyl-ester content on combustion chemistry of a biodiesel surrogate; 2) the effects of non-uniform particle sizes and fluid temperature on heat transfer characteristics of liquid water containing alumina nano-particles; 3) the effects of obstacle arrangements on transport of aerosol particles in channel flows. The investigation focuses on computational modeling and analysis in the above problems. In the first study, a kinetic modeling comparison of methyl butanoate and n-butane, its corresponding alkane, contrasts the combustion of methyl esters and normal alkanes, with the aim of understanding the effect of the methyl ester moiety. A fuel-breakdown model [J. Org. Chem. 2008, 73, 94; J. Phys. Chem. A 2008, 112, 51] is added to existing chemical kinetic mechanisms to improve the prediction of CO2 formation from MB decomposition. Sensitivity and reaction pathway analysis show that the absence of negative temperature coefficient behaviors and reduction of soot precursors can be ascribed to the effect of the methyl ester. The second study analyzes the heat transfer and fluid flow of natural convection in a cavity filled with Al2O3/water nanofluid that operates within differentially heated walls. The Navier-Stokes and energy equations are solved numerically, coupling the model of effective thermal conductivity [J. Phys. D 2006, 39, 4486] and model of effective dynamic viscosity [Appl. Phys. Lett. 2007, 91, 243112]. The numerical simulations explore the range where the heat transfer uncertainties can be affected by the operating conditions of the nanoparticles. Furthermore, the suppressed heat transfer phenomena are in good agreement with the latest experimental data of Ho et al. [Int. J. Therm. Sci. 2010, 49, 1345]. Finally, by using a simple lattice Boltzmann model coupled with a Lagrangian formalism, this study investigates the dispersion and deposition of aerosol particles over staggered obstacles in a two-dimensional channel flow. Particle motion mechanisms considered in the particle phase equation include drag, gravity, lift and Brownian forces. In this study, the results highlight the range of particle dimensions where the particle deposition can be affected by the arrangement of blocks placed in the channel flow. Advisors/Committee Members: Violi, Angela (committee member), Atreya, Arvind (committee member), Barker, John R. (committee member), Im, Hong G. (committee member).

Subjects/Keywords: Biodiesel; Chemical Kinetic Modeling; Nanofluids; Computational Fluid Dynamics; Aerosol Particles; Lattice Boltzmann; Mechanical Engineering; Engineering

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APA (6^th Edition):

Lin, K. C. (2011). Numerical Simulations of Thermal Systems-Applications To Fuel Chemistry, Nanofluid Heat Transfer And Aerosol Particle Transport. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/86287

Chicago Manual of Style (16^th Edition):

Lin, Kuang Chuan. “Numerical Simulations of Thermal Systems-Applications To Fuel Chemistry, Nanofluid Heat Transfer And Aerosol Particle Transport.” 2011. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/86287.

MLA Handbook (7^th Edition):

Lin, Kuang Chuan. “Numerical Simulations of Thermal Systems-Applications To Fuel Chemistry, Nanofluid Heat Transfer And Aerosol Particle Transport.” 2011. Web. 11 Apr 2021.

Vancouver:

Lin KC. Numerical Simulations of Thermal Systems-Applications To Fuel Chemistry, Nanofluid Heat Transfer And Aerosol Particle Transport. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/86287.

Council of Science Editors:

Lin KC. Numerical Simulations of Thermal Systems-Applications To Fuel Chemistry, Nanofluid Heat Transfer And Aerosol Particle Transport. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/86287

University of Michigan

4. Sankaran, Ramanan. A computational study of auto-ignition and flame propagation in stratified mixtures relevant to modern engines.

Degree: PhD, Mechanical engineering, 2004, University of Michigan

URL: http://hdl.handle.net/2027.42/124554

► Numerical simulations are performed to study the nature of auto-ignition and flame propagation in a stratified mixture. The results of this study are expected to… (more)

▼ Numerical simulations are performed to study the nature of auto-ignition and flame propagation in a stratified mixture. The results of this study are expected to provide a fundamental understanding of the combustion occurring in direct injection spark ignition (DISI) and homogeneous charge compression ignition (HCCI) engines. In the first part, the effect of time varying composition on a premixed methane-air flame is studied using a counterflow configuration and the concept of dynamic flammability limit is established to quantify the extension in flammability limit under unsteady situations. In addition, the effects of blending hydrogen to methane are studied as a possible means to improve the stability of lean premixed combustion. It is found that hydrogen blending substantially affects the diffusive-thermal stability while the dynamic response is unchanged. The second part of the dissertation is devoted to a fundamental study of ignition characteristics relevant to HCCI engines. Models at various levels of complexity are attempted, ranging from a homogenous reactor model to direct numerical simulation (DNS). First, the mixing of exhaust gas recirculation (EGR) on HCCI combustion are investigated for their benefit of knock reduction. Results obtained using a homogenous reactor model suggest that the effects of EGR is predominantly thermal than chemical for the conditions under study. This leads to a closer examination of the thermo-physical aspects of EGR on HCCI combustion due to incomplete mixing and mixture stratification. High-fidelity DNS studies are thus performed to assess the effects of the initial temperature distribution on ignition and subsequent heat release. For the three test cases considered, the presence of hotter core gas leads to early ignition and increased duration of burning, while a cold core leaves dormant end gas which is consumed by slow combustion. Finally, as a more extensive parametric study to quantify the effects of mixing rate on HCCI ignition, the ignition and propagation of a reaction front in a premixed fuel/air stream mixed with hotter exhaust gases is investigated using the counterflow configuration. The results provide a systematic framework to identify two distinct regimes of ignition, namely the spontaneous propagation and the deflagration regimes. A criterion based on the ratio of the time scales of auto-ignition and diffusion is proposed to identify the transition between these two regimes. Implications of the different regimes in the development of submodels for HCCI modeling are discussed. Advisors/Committee Members: Im, Hong G. (advisor).

Subjects/Keywords: Auto; Autoignition; Combustion; Computational; Engines; Flame Propagation; Ignition; Modern; Relevant; Stratified Mixtures; Study

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APA (6^th Edition):

Sankaran, R. (2004). A computational study of auto-ignition and flame propagation in stratified mixtures relevant to modern engines. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/124554

Chicago Manual of Style (16^th Edition):

Sankaran, Ramanan. “A computational study of auto-ignition and flame propagation in stratified mixtures relevant to modern engines.” 2004. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/124554.

MLA Handbook (7^th Edition):

Sankaran, Ramanan. “A computational study of auto-ignition and flame propagation in stratified mixtures relevant to modern engines.” 2004. Web. 11 Apr 2021.

Vancouver:

Sankaran R. A computational study of auto-ignition and flame propagation in stratified mixtures relevant to modern engines. [Internet] [Doctoral dissertation]. University of Michigan; 2004. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/124554.

Council of Science Editors:

Sankaran R. A computational study of auto-ignition and flame propagation in stratified mixtures relevant to modern engines. [Doctoral Dissertation]. University of Michigan; 2004. Available from: http://hdl.handle.net/2027.42/124554

University of Michigan

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

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

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

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

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

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

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APA (6^th Edition):

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

Chicago Manual of Style (16^th Edition):

Yoo, Chunsang. “Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects.” 2005. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/125553.

MLA Handbook (7^th Edition):

Yoo, Chunsang. “Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects.” 2005. Web. 11 Apr 2021.

Vancouver:

Yoo C. Direct numerical simulations of strained laminar and turbulent nonpremixed flames: Computational and physical aspects. [Internet] [Doctoral dissertation]. University of Michigan; 2005. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/125553.

Council of Science Editors:

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

6. Arias, Paul G. High-Fidelity Simulations to Study Spray-Induced Extinction and Particulate Formation Characteristics of Nonpremixed Ethylene-Air Flames.

Degree: PhD, Mechanical Engineering, 2013, University of Michigan

URL: http://hdl.handle.net/2027.42/97857

► This work developed and employed high-fidelity direct numerical simulations to investigate fundamental flame behavior in laminar and turbulence nonpremixed flames. The scope of the work… (more)

▼ This work developed and employed high-fidelity direct numerical simulations to investigate fundamental flame behavior in laminar and turbulence nonpremixed flames. The scope of the work includes several advances in computational algorithms such as improved Navier-Stokes Characteristic Boundary Conditions (NSCBC) for mass additive systems and advanced soot models. In addition, detailed investigations into the effects of thermal quenching were conducted in an effort to understand ways of accurately describing the nature of flame extinction comprehensively. As an application to fundamental and practical combustion problems, the study investigates the interaction of water spray and turbulence with nonpremixed diffusion flames. The simulations incorporate detailed chemistry of ethylene flames, the chemistry of which is recognized as an important chemical pathway for combustion processes. A unified extinction condition that accounts for thermal quenching and strain induced quenching simultaneously is demonstrated to be effective at capturing the moment of extinction and tracking extinction holes in turbulent flames. The findings show that in the formation of edge flames, the evolution leading to the flame recovery or total extinction is found to depend strongly on the temporal history of the local strain rate as well as the presence of the spray droplets. While turbulent mixing leads to the formation of the edge flames, the presence of spray droplets suppresses the ability of edge flames to heal extinction holes. The final part of this study examines the dynamics of soot formation in ethylene-air nonpremixed flames using a Method of Moments with Interpolative Closure (MOMIC) approach. A number of technical challenges related to the simulation of soot and gas phases were addressed. The treatment of the interpolation moments, which play a role in the diffusion of soot as well as the soot reaction source terms, was found to be consistent with the mathematic description of MOMIC, and was shown to be consistent with the conditions of statistical realizability of the soot moments for the reaction test cases. The results of this study provide the Direct Numerical Simulation (DNS) community with a numerical framework towards the development and implementation of high-fidelity soot sub-models. Advisors/Committee Members: Im, Hong G. (committee member), Ihme, Matthias (committee member), Atreya, Arvind (committee member), Violi, Angela (committee member).

Subjects/Keywords: Direct Numerical Simulation; Navier-Stokes Characteristics Boundary Conditions; Method of Moments With Interpolative Closure; Mechanical Engineering; Engineering

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APA (6^th Edition):

Arias, P. G. (2013). High-Fidelity Simulations to Study Spray-Induced Extinction and Particulate Formation Characteristics of Nonpremixed Ethylene-Air Flames. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/97857

Chicago Manual of Style (16^th Edition):

Arias, Paul G. “High-Fidelity Simulations to Study Spray-Induced Extinction and Particulate Formation Characteristics of Nonpremixed Ethylene-Air Flames.” 2013. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/97857.

MLA Handbook (7^th Edition):

Arias, Paul G. “High-Fidelity Simulations to Study Spray-Induced Extinction and Particulate Formation Characteristics of Nonpremixed Ethylene-Air Flames.” 2013. Web. 11 Apr 2021.

Vancouver:

Arias PG. High-Fidelity Simulations to Study Spray-Induced Extinction and Particulate Formation Characteristics of Nonpremixed Ethylene-Air Flames. [Internet] [Doctoral dissertation]. University of Michigan; 2013. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/97857.

Council of Science Editors:

Arias PG. High-Fidelity Simulations to Study Spray-Induced Extinction and Particulate Formation Characteristics of Nonpremixed Ethylene-Air Flames. [Doctoral Dissertation]. University of Michigan; 2013. Available from: http://hdl.handle.net/2027.42/97857

7. Cho, Jungdon. A Multi-Physics Model for Wet Clutch Dynamics.

Degree: PhD, Mechanical Engineering, 2012, University of Michigan

URL: http://hdl.handle.net/2027.42/91467

► A multi-physics model is developed for predicting the dynamic behavior of wet clutch engagement under realistic driving conditions. The transmission clutch plays a significant role… (more)

▼ A multi-physics model is developed for predicting the dynamic behavior of wet clutch engagement under realistic driving conditions. The transmission clutch plays a significant role in determining drivability and fuel economy. The present work overcomes previous limitations by constructing a detailed computational fluid dynamics model for wet clutch engagement. An open clutch model for single and multi-phase flow is developed. This model is used to provide the initial conditions for the dynamic engagement model. New extended boundary formulations are examined in order to reduce numerical errors at inlet and outlet boundaries. A new approach for squeeze-film flow is developed based on an iterative method. Given the external force responsible for plate movement, the squeeze velocity is computed by trial until the internal fluid stresses balance the external force. The latter are shown to have a major effect on squeeze-film flow and clutch engagement in general. The model also captures the flow in the micro-channels created by the grooves on the friction material surface and the flow through the porous friction material. The clutch engagement model combines the squeeze-film flow model with the influence of a rough surface on lubrication flow using the concept of flow factor, the mechanical contact based on the real contact area and the heat flux at the interface between the friction and separator using a virtual volume. A series of squeeze flow experiments were performed at the Ford Motor Company testing facility. The data are de-noised using standard statistical filters and then are used to validate the numerical results. Based on the comparison with the experimental data, the performance of the proposed model is found satisfactory. The wet clutch model developed in this research can become a baseline model for the prediction of the engagement behavior of a real wet clutch. When various material properties and further detailed geometric features are included, the present model may become an efficient alternative to laboratory testing and lead to designs that cannot be envisioned by other approaches. Advisors/Committee Members: Katopodes, Nikolaos D. (committee member), Stefanopoulou, Anna G. (committee member), Cotel, Aline J. (committee member), Im, Hong G. (committee member).

Subjects/Keywords: Multi-physics Model for Engagement and Open Clutch Process in Wet Clutch; Mechanical Engineering; Engineering

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APA (6^th Edition):

Cho, J. (2012). A Multi-Physics Model for Wet Clutch Dynamics. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/91467

Chicago Manual of Style (16^th Edition):

Cho, Jungdon. “A Multi-Physics Model for Wet Clutch Dynamics.” 2012. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/91467.

MLA Handbook (7^th Edition):

Cho, Jungdon. “A Multi-Physics Model for Wet Clutch Dynamics.” 2012. Web. 11 Apr 2021.

Vancouver:

Cho J. A Multi-Physics Model for Wet Clutch Dynamics. [Internet] [Doctoral dissertation]. University of Michigan; 2012. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/91467.

Council of Science Editors:

Cho J. A Multi-Physics Model for Wet Clutch Dynamics. [Doctoral Dissertation]. University of Michigan; 2012. Available from: http://hdl.handle.net/2027.42/91467

8. Alkandry, Hicham. Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells.

Degree: PhD, Aerospace Engineering and Scientific Computing, 2012, University of Michigan

URL: http://hdl.handle.net/2027.42/91580

► Future missions to Mars, including sample-return and human-exploration missions, may require alternative entry, descent, and landing technologies in order to perform pinpoint landing of heavy… (more)

▼ Future missions to Mars, including sample-return and human-exploration missions, may require alternative entry, descent, and landing technologies in order to perform pinpoint landing of heavy vehicles. Two such alternatives are propulsive deceleration (PD) and reaction control systems (RCS). PD can slow the vehicle during Mars atmospheric descent by directing thrusters into the incoming freestream. RCS can provide vehicle control and steering by inducing moments using thrusters on the back of the entry capsule. The use of these PD and RCS jets, however, involves complex flow interactions that are still not well understood. The fluid interactions induced by PD and RCS jets for Mars-entry vehicles in hypersonic freestream conditions are investigated using computational fluid dynamics (CFD). The effects of central and peripheral PD configurations using both sonic and supersonic jets at various thrust conditions are examined in this dissertation. The RCS jet is directed either parallel or transverse to the freestream flow at different thrust conditions in order to examine the effects of the thruster orientation with respect to the center of gravity of the aeroshell. The physical accuracy of the computational method is also assessed by comparing the numerical results with available experimental data. The central PD configuration decreases the drag force acting on the entry capsule due to a shielding effect that prevents mass and momentum in the hypersonic freestream from reaching the aeroshell. The peripheral PD configuration also decreases the drag force by obstructing the flow around the aeroshell and creating low surface pressure regions downstream of the PD nozzles. The Mach number of the PD jets, however, does not have a significant effect on the induced fluid interactions. The reaction control system also alters the flowfield, surface, and aerodynamic properties of the aeroshell, while the jet orientation can have a significant effect on the control effectiveness of the RCS. Advisors/Committee Members: Boyd, Iain D. (committee member), Fidkowski, Krzysztof J. (committee member), Im, Hong G. (committee member), McDaniel, James C. (committee member).

Subjects/Keywords: Propulsive Deceleration; Reaction Control System; Computational Fluid Dynamics; Hypersonic Flow; Aerospace Engineering; Engineering

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APA (6^th Edition):

Alkandry, H. (2012). Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/91580

Chicago Manual of Style (16^th Edition):

Alkandry, Hicham. “Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells.” 2012. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/91580.

MLA Handbook (7^th Edition):

Alkandry, Hicham. “Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells.” 2012. Web. 11 Apr 2021.

Vancouver:

Alkandry H. Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells. [Internet] [Doctoral dissertation]. University of Michigan; 2012. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/91580.

Council of Science Editors:

Alkandry H. Aerodynamic Interactions of Propulsive Deceleration and Reaction Control System Jets on Mars-Entry Aeroshells. [Doctoral Dissertation]. University of Michigan; 2012. Available from: http://hdl.handle.net/2027.42/91580

9. Chung, Seung-Hyun. Computational Modeling of Soot Nucleation.

Degree: PhD, Mechanical Engineering, 2011, University of Michigan

URL: http://hdl.handle.net/2027.42/86455

► Recent studies indicate that soot is the second most significant driver of climate change - behind CO2, but ahead of methane - and increased levels… (more)

Subjects/Keywords: Soot Nucleation; Mechanical Engineering; Engineering

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APA (6^th Edition):

Chung, S. (2011). Computational Modeling of Soot Nucleation. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/86455

Chicago Manual of Style (16^th Edition):

Chung, Seung-Hyun. “Computational Modeling of Soot Nucleation.” 2011. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/86455.

MLA Handbook (7^th Edition):

Chung, Seung-Hyun. “Computational Modeling of Soot Nucleation.” 2011. Web. 11 Apr 2021.

Vancouver:

Chung S. Computational Modeling of Soot Nucleation. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/86455.

Council of Science Editors:

Chung S. Computational Modeling of Soot Nucleation. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/86455

10. Bansal, Gaurav. Computational Studies of Autoignition and Combustion in Low Temperature Combustion Engine Environments.

Degree: PhD, Mechanical Engineering, 2009, University of Michigan

URL: http://hdl.handle.net/2027.42/63726

► Computational studies are performed on the autoignition and combustion characteristics encountered in modern internal combustion (IC) engines in which combustion is achieved primarily by autoignition… (more)

▼ Computational studies are performed on the autoignition and combustion characteristics encountered in modern internal combustion (IC) engines in which combustion is achieved primarily by autoignition of the reactant mixture. High-fidelity computational tools with varying levels of complexity are employed in order to systematically investigate the phenomena under consideration. As a first baseline study, the effects of unsteady temperature fluctuations on the ignition of homogeneous hydrogen-air mixture in a constant-volume reactor is studied both computationally and theoretically using asymptotic analysis. It is found that ignition delay shows a harmonic response to the frequency of imposed temperature fluctuation and the response monotonically attenuates as frequency increases. The effects of spatial transport on the autoignition characteristics are next investigated using a one-dimensional counterflow configuration, in which unsteady scalar dissipation rate represents the effects of turbulent flow field. A newly defined ignitability parameter is proposed which systematically accounts for all the unsteady effects. n-Heptane, which exhibits a two-stage ignition behavior is studied next using similar configuration. Interestingly, two-stage ignition is observed even at significantly high initial temperatures when the ignition kernel is subjected to unsteady scalar dissipation rate. Mechanism for the appearance of two-stage ignition in unsteady conditions is found to be not chemical but is attributed to the spatial broadening of the ignition kernel and subsequent radical losses. Guided by the above findings, multi-dimensional simulations are conducted to investigate the effects of spatial fluctuations in temperature and composition. Non-reacting 3D RANS engine simulations are first conducted to investigate different mixture formation scenarios that might exist in LTC engines prior to autoignition. Small-scale effects of these different mixture formation scenarios on the autoignition and subsequent front propagation are then studied using high-fidelity direct numerical simulation (DNS). In the last part of dissertation, a novel principal component analysis (PCA) based approach is used to identify intrinsic low-dimensional manifolds in a complex autoigniting environment. A small number of principal components (PCs) are found to very well represent the complex reacting system. The approach thus provides a promising modeling strategy to reduce the computational complexity in solving realistic detailed chemistry in mixed-mode combustion systems. Advisors/Committee Members: Im, Hong G. (committee member), Driscoll, James F. (committee member), Filipi, Zoran S. (committee member), Wooldridge, Margaret S. (committee member).

Subjects/Keywords: Combustion; Low Temperature Combustion Engines; Autoignition; Low Dimensional Manifolds; Direct Numerical Simulation; Computational Fluid Dynamics; Mechanical Engineering; Engineering

…visualization of combustion in the rapid compression facility at University of Michigan has shown the…

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APA (6^th Edition):

Bansal, G. (2009). Computational Studies of Autoignition and Combustion in Low Temperature Combustion Engine Environments. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/63726

Chicago Manual of Style (16^th Edition):

Bansal, Gaurav. “Computational Studies of Autoignition and Combustion in Low Temperature Combustion Engine Environments.” 2009. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/63726.

MLA Handbook (7^th Edition):

Bansal, Gaurav. “Computational Studies of Autoignition and Combustion in Low Temperature Combustion Engine Environments.” 2009. Web. 11 Apr 2021.

Vancouver:

Bansal G. Computational Studies of Autoignition and Combustion in Low Temperature Combustion Engine Environments. [Internet] [Doctoral dissertation]. University of Michigan; 2009. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/63726.

Council of Science Editors:

Bansal G. Computational Studies of Autoignition and Combustion in Low Temperature Combustion Engine Environments. [Doctoral Dissertation]. University of Michigan; 2009. Available from: http://hdl.handle.net/2027.42/63726

11. Hassan, Ezeldin A. Multi-fluid Dynamics for Supersonic Jet-and-Crossflows and Liquid Plug Rupture.

Degree: PhD, Aerospace Engineering, 2012, University of Michigan

URL: http://hdl.handle.net/2027.42/91550

► Multi-fluid dynamics simulations require appropriate numerical treatments based on the main flow characteristics, such as flow speed, turbulence, thermodynamic state, and time and length scales.… (more)

▼ Multi-fluid dynamics simulations require appropriate numerical treatments based on the main flow characteristics, such as flow speed, turbulence, thermodynamic state, and time and length scales. In this thesis, two distinct problems are investigated: supersonic jet and crossflow interactions; and liquid plug propagation and rupture in an airway. Gaseous non-reactive ethylene jet and air crossflow simulation represents essential physics for fuel injection in SCRAMJET engines. The regime is highly unsteady, involving shocks, turbulent mixing, and large-scale vortical structures. An eddy-viscosity-based multi-scale turbulence model is proposed to resolve turbulent structures consistent with grid resolution and turbulence length scales. Predictions of the time-averaged fuel concentration from the multi-scale model are improved over Reynolds-averaged Navier-Stokes models originally derived from stationary flow. The response to the multi-scale model alone is, however, limited, in cases where the vortical structures are small and scattered thus requiring prohibitively expensive grids in order to resolve the flow field accurately. Statistical information related to turbulent fluctuations is utilized to estimate an effective turbulent Schmidt number, which is shown to be highly varying in space. Accordingly, an adaptive turbulent Schmidt number approach is proposed, by allowing the resolved field to adaptively influence the value of turbulent Schmidt number in the multi-scale turbulence model. The proposed model estimates a time-averaged turbulent Schmidt number adapted to the computed flow field, instead of the constant value common to the eddy-viscosity-based Navier-Stokes models. This approach is assessed using a grid-refinement study for the normal injection case, and tested with 30 degree injection, showing improved results over the constant turbulent Schmidt model both in mean and variance of fuel concentration predictions. For the incompressible liquid plug propagation and rupture study, numerical simulations are conducted using an Eulerian-Lagrangian approach with a continuous-interface method. A reconstruction scheme is developed to allow topological changes during plug rupture by altering the connectivity information of the interface mesh. Rupture time is shown to be delayed as the initial precursor film thickness increases. During the plug rupture process, a sudden increase of mechanical stresses on the tube wall is recorded, which can cause tissue damage. Advisors/Committee Members: Powell, Ken (committee member), Shyy, Wei (committee member), Davis, Douglas L. (committee member), Driscoll, James F. (committee member), Im, Hong G. (committee member).

Subjects/Keywords: Supersonic Crossflow; Turbulence Modeling; Schmidt Number; Plug Flow; Multiphase Flow; Engineering

…Energy UM: University of Michigan xviii Abstract Multi-fluid dynamics simulations require…

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APA (6^th Edition):

Hassan, E. A. (2012). Multi-fluid Dynamics for Supersonic Jet-and-Crossflows and Liquid Plug Rupture. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/91550

Chicago Manual of Style (16^th Edition):

Hassan, Ezeldin A. “Multi-fluid Dynamics for Supersonic Jet-and-Crossflows and Liquid Plug Rupture.” 2012. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/91550.

MLA Handbook (7^th Edition):

Hassan, Ezeldin A. “Multi-fluid Dynamics for Supersonic Jet-and-Crossflows and Liquid Plug Rupture.” 2012. Web. 11 Apr 2021.

Vancouver:

Hassan EA. Multi-fluid Dynamics for Supersonic Jet-and-Crossflows and Liquid Plug Rupture. [Internet] [Doctoral dissertation]. University of Michigan; 2012. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/91550.

Council of Science Editors:

Hassan EA. Multi-fluid Dynamics for Supersonic Jet-and-Crossflows and Liquid Plug Rupture. [Doctoral Dissertation]. University of Michigan; 2012. Available from: http://hdl.handle.net/2027.42/91550

12. Chae, Kyungchan. Mass Diffusion and Chemical Kinetic Data for Jet Fuel Surrogates.

Degree: PhD, Mechanical Engineering, 2010, University of Michigan

URL: http://hdl.handle.net/2027.42/78769

► The predictive capability of combustion modeling is directly related to the accuracy of the models and data used for molecular transport and chemical kinetics. In… (more)

▼ The predictive capability of combustion modeling is directly related to the accuracy of the models and data used for molecular transport and chemical kinetics. In this work, we report on improvements in both categories. The gas kinetic theory (GKT) has been widely used to determine the transport properties of gas-phase molecules because of its simplicity and the lack of experimental data, especially at high temperatures. The major focus of this thesis is to determine the transport properties of complex molecules and suggest an alternative way to overcome the limitations of GKT, especially for large polyatomic molecules. We also recommend a correction term to the expression of the diffusion coefficients that allows the expansion of the validity of the GKT to include molecules with complex geometries and systems at high temperatures. We compute the diffusion coefficients for three classes of hydrocarbons (linear alkanes, cycloalkanes and aromatic molecules) using Molecular Dynamics (MD) simulations with all-atom potentials to incorporate the effects of molecular configurations. The results are compared with the values obtained using GKT, showing that the latter theory overestimates the diffusion of large polyatomic molecules and the error increases for molecules of significantly non-spherical shape. A detailed analysis of the relative importance of the potentials used for MD simulations and the structures of the molecules highlights the importance of the molecular shape in evaluating accurate diffusion coefficients. We also proposed a correction term for the collision diameter used in GKT, based on the radii of gyration of molecules. In the field of chemical kinetics, we report on the reaction mechanisms for the decomposition of decalin, one of the main components of jet fuel surrogates. We identify fifteen reaction pathways and determine the reaction rates using ab-initio techniques and transition state theory. The new kinetic mechanism of decalin is used to study the combustion of decalin showing the importance of the new reactions in predicting combustion products. Advisors/Committee Members: Violi, Angela (committee member), Elvati, Paolo (committee member), Im, Hong G. (committee member), Lastoskie, Christian M. (committee member), Wooldridge, Margaret S. (committee member).

Subjects/Keywords: Mass Diffusion Coefficients; Mechanical Engineering; Engineering

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APA (6^th Edition):

Chae, K. (2010). Mass Diffusion and Chemical Kinetic Data for Jet Fuel Surrogates. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/78769

Chicago Manual of Style (16^th Edition):

Chae, Kyungchan. “Mass Diffusion and Chemical Kinetic Data for Jet Fuel Surrogates.” 2010. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/78769.

MLA Handbook (7^th Edition):

Chae, Kyungchan. “Mass Diffusion and Chemical Kinetic Data for Jet Fuel Surrogates.” 2010. Web. 11 Apr 2021.

Vancouver:

Chae K. Mass Diffusion and Chemical Kinetic Data for Jet Fuel Surrogates. [Internet] [Doctoral dissertation]. University of Michigan; 2010. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/78769.

Council of Science Editors:

Chae K. Mass Diffusion and Chemical Kinetic Data for Jet Fuel Surrogates. [Doctoral Dissertation]. University of Michigan; 2010. Available from: http://hdl.handle.net/2027.42/78769

13. Gupta, Saurabh. High-Fidelity Simulation and Analysis of Ignition Regimes and Mixing Characteristics for Low Temperature Combustion Engine Applications.

Degree: PhD, Mechanical Engineering, 2012, University of Michigan

URL: http://hdl.handle.net/2027.42/93944

► Computational singular perturbation (CSP) technique is applied as an automated diagnostic tool to classify ignition regimes in low temperature combustion (LTC) engine environments. Various problems… (more)

▼ Computational singular perturbation (CSP) technique is applied as an automated diagnostic tool to classify ignition regimes in low temperature combustion (LTC) engine environments. Various problems representing LTC are simulated using high-fidelity computation with detailed chemistry for hydrogen-air, and the simulation data are then analyzed by CSP. The active reaction zones are first identified by the locus of minimum number of fast exhausted time scales. Subsequently, the relative importance of transport and chemistry is determined in the region ahead of the reaction zone. A new index I T , defined as the sum of the absolute values of the importance indices of diffusion and convection of temperature to the slow dynamics of temperature, serves as a criterion to differentiate spontaneous ignition from deflagration regimes. The same strategy is then used to classify ignition regimes in n-heptane air mixtures. Parametric studies are conducted using high-fidelity simulations with detailed chemistry and transport. The mixture at non-NTC conditions shows initially a deflagration front which is subsequently transitioned into a spontaneous ignition front. For the mixtures at the NTC conditions which exhibit two-stage ignition behavior, the 1st stage ignition front is found to be more likely in the deflagration regime. On the other hand, the 2nd stage ignition front occurs almost always in the spontaneous regime because the upstream mixture contains active radical species produced by the preceding 1st stage ignition front. The effects of differently correlated equivalence ratio stratification are also considered and the results are shown to be consistent with previous findings. 2D turbulent auto-ignition problems corresponding to NTC and non-NTC chemistry yield similar qualitative results. Finally, we look into the modeling of turbulent mixing, in particular, the scalar dissipation rate, in the context of flamelet approach. This involves a number of aspects: (i) probability density functions, (ii) mean scalar dissipation rates, and (iii) conditional scalar dissipation rates, for mixture fraction (Z) and total enthalpy (H). The validity of existing models both in the RANS and LES contexts is assessed, and alternative models are proposed to improve on the above three aspects. Advisors/Committee Members: Im, Hong G. (committee member), Ihme, Matthias (committee member), Atreya, Arvind (committee member), Valorani, Mauro (committee member), Violi, Angela (committee member).

Subjects/Keywords: Low Temperature Combustion (LTC); Computational Singular Perturbation (CSP); Ignition Regimes; Scalar Dissipation Rate Modeling; Direct Numerical Simulation (DNS); Mechanical Engineering; Engineering

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APA (6^th Edition):

Gupta, S. (2012). High-Fidelity Simulation and Analysis of Ignition Regimes and Mixing Characteristics for Low Temperature Combustion Engine Applications. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/93944

Chicago Manual of Style (16^th Edition):

Gupta, Saurabh. “High-Fidelity Simulation and Analysis of Ignition Regimes and Mixing Characteristics for Low Temperature Combustion Engine Applications.” 2012. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/93944.

MLA Handbook (7^th Edition):

Gupta, Saurabh. “High-Fidelity Simulation and Analysis of Ignition Regimes and Mixing Characteristics for Low Temperature Combustion Engine Applications.” 2012. Web. 11 Apr 2021.

Vancouver:

Gupta S. High-Fidelity Simulation and Analysis of Ignition Regimes and Mixing Characteristics for Low Temperature Combustion Engine Applications. [Internet] [Doctoral dissertation]. University of Michigan; 2012. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/93944.

Council of Science Editors:

Gupta S. High-Fidelity Simulation and Analysis of Ignition Regimes and Mixing Characteristics for Low Temperature Combustion Engine Applications. [Doctoral Dissertation]. University of Michigan; 2012. Available from: http://hdl.handle.net/2027.42/93944

14. Tsai, Chung-Yin. A Computational Model for Pyrolysis, Heat Transfer, and Combustion in a Fixed-bed Waste Gasifier.

Degree: PhD, Mechanical Engineering, 2011, University of Michigan

URL: http://hdl.handle.net/2027.42/84482

► The overarching goal of the study presented in this dissertation is to develop a predictive computational model that can describe the detailed chemical and physical… (more)

▼ The overarching goal of the study presented in this dissertation is to develop a predictive computational model that can describe the detailed chemical and physical processes associated with pyrolysis, heat transfer and combustion for solid waste in a fixed bed gasifier. The work is applicable to optimization and prediction of the synthetic gas composition of solid waste gasifier operations. The dissertation is comprised of two main parts. In the first part, a predictive three-dimensional model for municipal solid waste gasification process is developed. The multiphase flow is described by a porous flow model using the SIMPLE algorithm with momentum interpolation. The governing equations are transformed into a generalized coordinate system to be applicable to realistic reactor geometry. A simplified global reaction mechanism is adapted for the gas-phase chemical reactions inside the gasifier. The pyrolysis process is described by a phenomenological Lagrangian pyrolysis model to determine the local porosity distribution and the corresponding pyrolysis rate of the waste. Computational results show three-dimensional distribution of the flow field, temperature, species concentration, porosity and the stack morphology under different parametric conditions. The effects of the inlet temperature and the feeding rate on the waste stack shape are studied. The results demonstrate that the model can properly capture the essential physical and chemical processes in the gasifier and thus can be used as a predictive simulation tool. In the second part, the Lagrangian pyrolysis model is extended to consider a multiple characteristic diameter (MCD) pyrolysis submodel in order to independently determine the rate of the local devolatilization, drying and charring processes associated with realistic biomass fuels. The porosity distribution is determined by introducing the local characteristic diameter of the virtual solid spheres representing the biomass fuel. Global homogeneous and heterogeneous reactions were adapted for the chemical reactions inside the gasifier. Synthetic gas compositions from model prediction are validated experiments conducted by Korean Institute of Energy Research (KIER) with good agreements. Model predictions are also compared with the results calculated by the equilibrium model in order to demonstrate that the proposed model improves the predictive capability of the complex nonequilibrium processes inside the gasifier. Advisors/Committee Members: Im, Hong G. (committee member), Atreya, Arvind (committee member), Driscoll, James F. (committee member), Kim, Taig-Young (committee member), Violi, Angela (committee member).

Subjects/Keywords: Biomass Gasification Modeling; Refuse-derived Fuel; Wood Pyrolysis; Devolatilization; Mechanical Engineering; Engineering

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APA (6^th Edition):

Tsai, C. (2011). A Computational Model for Pyrolysis, Heat Transfer, and Combustion in a Fixed-bed Waste Gasifier. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/84482

Chicago Manual of Style (16^th Edition):

Tsai, Chung-Yin. “A Computational Model for Pyrolysis, Heat Transfer, and Combustion in a Fixed-bed Waste Gasifier.” 2011. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/84482.

MLA Handbook (7^th Edition):

Tsai, Chung-Yin. “A Computational Model for Pyrolysis, Heat Transfer, and Combustion in a Fixed-bed Waste Gasifier.” 2011. Web. 11 Apr 2021.

Vancouver:

Tsai C. A Computational Model for Pyrolysis, Heat Transfer, and Combustion in a Fixed-bed Waste Gasifier. [Internet] [Doctoral dissertation]. University of Michigan; 2011. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/84482.

Council of Science Editors:

Tsai C. A Computational Model for Pyrolysis, Heat Transfer, and Combustion in a Fixed-bed Waste Gasifier. [Doctoral Dissertation]. University of Michigan; 2011. Available from: http://hdl.handle.net/2027.42/84482

15. Kodavasal, Janardhan. Effect of Charge Preparation Strategy on HCCI Combustion.

Degree: PhD, Mechanical Engineering, 2013, University of Michigan

URL: http://hdl.handle.net/2027.42/99766

► A critical factor determining Homogeneous Charge Compression Ignition (HCCI) combustion characteristics and emissions is preparation of the fuel-diluent charge prior to ignition. The choice of… (more)

▼ A critical factor determining Homogeneous Charge Compression Ignition (HCCI) combustion characteristics and emissions is preparation of the fuel-diluent charge prior to ignition. The choice of charge preparation strategy impacts diluent composition and stratification. Presently, there is a gap in fundamental understanding as to the impact of these strategies on charge distribution within the reaction space and consequent effects on HCCI combustion. In this doctoral work, fully-coupled CFD/chemical kinetics simulations are performed for various competing charge preparation strategies at a typical HCCI operating point to study the differences in burn duration and emissions arising from these strategies. The strategies studied are: air versus external EGR dilution, Negative Valve Overlap (NVO) versus Positive Valve Overlap (PVO) operation, and premixed fueling versus direct injection. The CFD reaction space is analyzed to determine the reactivity stratification prior to ignition arising from each of these strategies. A sequential CFD-multi-zone model is developed as a diagnostic tool wherein CFD simulation is performed over the gas exchange period until a transition point before TDC, after which the CFD reaction space is mapped onto a multi-zone chemical kinetic model. This tool is used to decouple various concurrent effects. For example, by selectively choosing to map thermal stratification from the CFD domain onto the multi-zone model while ignoring compositional stratification, the relative contributions of thermal and compositional stratification arising from NVO operation are isolated. Based on these insights from CFD, a standalone quasi-dimensional HCCI combustion model incorporating kinetics is built, featuring a computationally efficient methodology (developed as part of this work) to capture wall heat loss driven thermal stratification, as an alternative to expensive CFD simulation. It is shown that predictions from this model correspond well with results from detailed CFD/kinetics simulations over a range of operating conditions, for different engine geometries, while being up to two-orders of magnitude faster than CFD, making this model ideal for use in system-level codes. Advisors/Committee Members: Assanis, Dionissios N. (committee member), Im, Hong G. (committee member), Driscoll, James F. (committee member), Martz, Jason Brian (committee member), Babajimopoulos, Aristotelis (committee member), Borgnakke, Claus (committee member), Lavoie, George A. (committee member).

Subjects/Keywords: HCCI; Combustion; Internal Combustion Engine; Stratification; CFD; Negative Valve Overlap; Mechanical Engineering; Engineering

…Figure 6.5 – University of Michigan FFVA engine CFD mesh…

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APA (6^th Edition):

Kodavasal, J. (2013). Effect of Charge Preparation Strategy on HCCI Combustion. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/99766

Chicago Manual of Style (16^th Edition):

Kodavasal, Janardhan. “Effect of Charge Preparation Strategy on HCCI Combustion.” 2013. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/99766.

MLA Handbook (7^th Edition):

Kodavasal, Janardhan. “Effect of Charge Preparation Strategy on HCCI Combustion.” 2013. Web. 11 Apr 2021.

Vancouver:

Kodavasal J. Effect of Charge Preparation Strategy on HCCI Combustion. [Internet] [Doctoral dissertation]. University of Michigan; 2013. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/99766.

Council of Science Editors:

Kodavasal J. Effect of Charge Preparation Strategy on HCCI Combustion. [Doctoral Dissertation]. University of Michigan; 2013. Available from: http://hdl.handle.net/2027.42/99766

University of Michigan

16. Vanzieleghem, Bruno P. Combustion modeling for gasoline direct injection engines using KIVA-3V.

Degree: PhD, Mechanical engineering, 2004, University of Michigan

URL: http://hdl.handle.net/2027.42/124201

► An extended coherent flamelet model was implemented in the computational fluid dynamics code KIVA-3V to achieve high fidelity simulation of gasoline direct injection (GDI) combustion.… (more)

▼ An extended coherent flamelet model was implemented in the computational fluid dynamics code KIVA-3V to achieve high fidelity simulation of gasoline direct injection (GDI) combustion. The model allows for the identification of fuel economy improvements and emissions implications for this technology, in addition to the investigation of new operating strategies. An extensive validation of all aspects of the simulation with experimental results was performed. In the coherent flame model, the flame is represented by a transport equation for flame density, with modeled terms for the production and destruction. Stratification of the engine charge is incorporated by diagnostic equations for the unburned fuel, oxygen, and enthalpy. This allows the characterization of the gas properties on a conditionally-averaged basis, by separately averaging over the burned or unburned fraction in a computational cell. The conditionally-averaged burned gas temperature can then be used to calculate the emissions formation rates, leading to more accurate predictions. The coherent flame model was extended, to capture the effects of exhaust gas recirculation stratification on combustion and pollutant formation, by adding a new diagnostics equation for CO₂ originating from exhaust gas recirculation. A near-wall flame treatment was also implemented to represent the realistic behavior of the flame near the walls more accurately. Since the literature lacks integrated studies thoroughly validating models developed specifically for GDI engines, the combustion model was integrated with updated models for spray breakup and spray wall impingement. This complete model was then used to simulate the engine cycle of an optical 4-valve GDI engine, corresponding to an experimental GDI engine. Laser-induced fluorescence (LIF) experiments, in combination with traditional engine diagnostics, allowed us to validate the simulation by comparing air motion, mixture formation, and combustion data over a range of speed and load conditions, in a realistic engine geometry, including moving valves. The thorough validation of all aspects of the model for the complete engine cycle demonstrates how the model was able to capture the important characteristics of the GDI engine, and pointed to areas that require further improvements. Advisors/Committee Members: Assanis, Dennis N. (advisor), Im, Hong G. (advisor).

Subjects/Keywords: 3v; Combustion; Direct-injection; Engines; Fuel Economy; Gasoline; Kiva; Modeling; Using

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APA (6^th Edition):

Vanzieleghem, B. P. (2004). Combustion modeling for gasoline direct injection engines using KIVA-3V. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/124201

Chicago Manual of Style (16^th Edition):

Vanzieleghem, Bruno P. “Combustion modeling for gasoline direct injection engines using KIVA-3V.” 2004. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/124201.

MLA Handbook (7^th Edition):

Vanzieleghem, Bruno P. “Combustion modeling for gasoline direct injection engines using KIVA-3V.” 2004. Web. 11 Apr 2021.

Vancouver:

Vanzieleghem BP. Combustion modeling for gasoline direct injection engines using KIVA-3V. [Internet] [Doctoral dissertation]. University of Michigan; 2004. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/124201.

Council of Science Editors:

Vanzieleghem BP. Combustion modeling for gasoline direct injection engines using KIVA-3V. [Doctoral Dissertation]. University of Michigan; 2004. Available from: http://hdl.handle.net/2027.42/124201

University of Michigan

17. Sozer, Emre. Modeling of Gaseous Reacting Flow and Thermal Environment of Liquid Rocket Injectors.

Degree: PhD, Aerospace Engineering, 2010, University of Michigan

URL: http://hdl.handle.net/2027.42/77684

► Reacting flow and thermal fields around the injector critically affect the performance and life of liquid rocket engines. The performance gain by enhanced mixing is… (more)

▼ Reacting flow and thermal fields around the injector critically affect the performance and life of liquid rocket engines. The performance gain by enhanced mixing is often countered by increased heat flux to the chamber wall, which can result in material failure. A CFD based design approach can aid in optimization of competing objectives by providing detailed flow field data and an ability to feasibly evaluate a large number of design configurations. To address issues related to the CFD analysis of such flows, various turbulence and combustion modeling aspects are assessed. Laminar finite-rate chemistry and steady laminar flamelet combustion models are adopted to facilitate individual assessments of turbulence-chemistry interactions (TCI) and chemical non-equilibrium. Besides the experimental wall heat transfer information, assessments are aided by evaluations of time scales, grid sensitivity, wall treatments and kinetic schemes. Several multi-element injector configurations are considered to study element-to-element interactions. Under the conditions considered, chemical non-equilibrium effect is found to be unimportant. TCI is found to noticeably alter the flow and thermal fields near the injector and the flame surface. In the multi-element injector case, due to proximity of the outer row injector elements to the wall, wall heat flux distribution is also significantly affected by TCI. The near wall treatment is found to critically affect wall heat flux predictions. A zonal treatment, blending the low-Reynolds number model and the law-of-the-wall approach is shown to improve the accuracy significantly. Porous materials such as Rigimesh are often used as the injector face plate of liquid rocket engines. A multi-scale model, which eliminates the empirical dependence of conventional analysis methods, is developed. The resulting model is tested using experimental information showing excellent agreement. The model development and assessment presented for both injector flows and transport in porous materials will be valuable for advancement of computational tools aiding design and analysis of liquid rocket engine flows. Towards this end, further challenges such as the modeling of liquid propellants and the atomization process, detailed characterization of the Rigimesh material and more rigorous validation need to be addressed. Advisors/Committee Members: Ihme, Matthias (committee member), Shyy, Wei (committee member), Driscoll, James F. (committee member), Im, Hong G. (committee member).

Subjects/Keywords: Liquid Rocket; Injector; Computational Fluid Dynamics; Turbulent Reacting Flow; Aerospace Engineering; Engineering

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APA (6^th Edition):

Sozer, E. (2010). Modeling of Gaseous Reacting Flow and Thermal Environment of Liquid Rocket Injectors. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/77684

Chicago Manual of Style (16^th Edition):

Sozer, Emre. “Modeling of Gaseous Reacting Flow and Thermal Environment of Liquid Rocket Injectors.” 2010. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/77684.

MLA Handbook (7^th Edition):

Sozer, Emre. “Modeling of Gaseous Reacting Flow and Thermal Environment of Liquid Rocket Injectors.” 2010. Web. 11 Apr 2021.

Vancouver:

Sozer E. Modeling of Gaseous Reacting Flow and Thermal Environment of Liquid Rocket Injectors. [Internet] [Doctoral dissertation]. University of Michigan; 2010. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/77684.

Council of Science Editors:

Sozer E. Modeling of Gaseous Reacting Flow and Thermal Environment of Liquid Rocket Injectors. [Doctoral Dissertation]. University of Michigan; 2010. Available from: http://hdl.handle.net/2027.42/77684

University of Michigan

18. Wiswall, James T. Catalysis of Propane Oxidation and Premixed Propane-Air Flames.

Degree: PhD, Mechanical Engineering, 2009, University of Michigan

URL: http://hdl.handle.net/2027.42/64735

► Improvements in deriving energy from hydrocarbon fuels will have a large impact on our efforts to transition to sustainable and renewable energy resources. The hypothesis… (more)

▼ Improvements in deriving energy from hydrocarbon fuels will have a large impact on our efforts to transition to sustainable and renewable energy resources. The hypothesis is that catalysis can extend the useful operating conditions for hydrocarbon oxidation and combustion, improve device efficiencies, and reduce pollutants. Catalysis of propane oxidation and premixed propane-air flames are examined experimentally, using a stagnation-flow reactor to identify the important physical and chemical mechanisms over a range of flow, catalyst, and temperature conditions. The propane oxidation studies consider five catalyst materials: platinum, palladium, SnO2, 90% SnO2 – 10% Pt (by mass), and quartz. The volume fractions of CO2, O2, C3H8, CO, NO and the electric power required to control the catalyst temperature quantify the activity of each catalyst for the equivalence ratios of 0.67, 1.00, and 1.50, and over the catalyst temperature range 23-800 °C. Quartz is used as a baseline and confirmed to be non-reactive at all conditions. 100% SnO2 has minimal reactivity. Platinum, palladium, and 90% SnO2 – 10% Pt show similar trends and have the highest catalytic activity for the fuel rich mixture. Palladium and 90% SnO2 – 10% Pt show an increasing catalyst-activation temperature (Tsa) for decreasing equivalence ratio, and platinum shows an approximately constant catalyst-activation temperature for decreasing equivalence ratio (Tsa = 310 °C). Of these the 90% SnO2 – 10% Pt catalyst shows the lowest Tsa, occurring for the fuel-rich mixture (Tsa = 250 °C). The studies of premixed propane-air flames consider platinum and quartz stagnation surfaces for fuel-mixture velocities from 0.6-1.6 m/s. Five flame structures are observed: cool core envelope, cone, envelope, disk, and ring flames. The lean-extinction limit, disk-to-ring flame transition mixture, and the disk-flame to stagnation-plane distance are reported. Platinum inhibits the ring flame structure. The lean-extinction limit and disk-flame to stagnation-plane separation distance are insensitive to the stagnation-plane material. The results set directions for development of improved catalyst systems, including the development of lean NOx catalysts with low light-off temperatures, methods to quantify catalyst aging and poisoning properties, and fundamental data to develop models of the catalyst chemistry for the design of novel energy generation techniques. Advisors/Committee Members: Im, Hong G. (committee member), Wooldridge, Margaret S. (committee member), Atreya, Arvind (committee member), Ihme, Matthias (committee member).

Subjects/Keywords: Catalytic Combustion; Platinum; Palladium; Tin Dioxide; Propane Oxidation; Catalytic Oxidation; Mechanical Engineering; Engineering

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

APA (6^th Edition):

Wiswall, J. T. (2009). Catalysis of Propane Oxidation and Premixed Propane-Air Flames. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/64735

Chicago Manual of Style (16^th Edition):

Wiswall, James T. “Catalysis of Propane Oxidation and Premixed Propane-Air Flames.” 2009. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/64735.

MLA Handbook (7^th Edition):

Wiswall, James T. “Catalysis of Propane Oxidation and Premixed Propane-Air Flames.” 2009. Web. 11 Apr 2021.

Vancouver:

Wiswall JT. Catalysis of Propane Oxidation and Premixed Propane-Air Flames. [Internet] [Doctoral dissertation]. University of Michigan; 2009. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/64735.

Council of Science Editors:

Wiswall JT. Catalysis of Propane Oxidation and Premixed Propane-Air Flames. [Doctoral Dissertation]. University of Michigan; 2009. Available from: http://hdl.handle.net/2027.42/64735

University of Michigan

19. Keum, Seung Hwan. An Improved Representative Interactive Flamelet Model Accounting for Evaporation Effect in Reaction Space (RIF-ER).

Degree: PhD, Mechanical Engineering, 2009, University of Michigan

URL: http://hdl.handle.net/2027.42/62293

► Recently, applications of spray combustion in internal combustion engines (ICE) are being expanded from conventional to gasoline direct injection engines. Moreover, stratification using spray is… (more)

▼ Recently, applications of spray combustion in internal combustion engines (ICE) are being expanded from conventional to gasoline direct injection engines. Moreover, stratification using spray is further considered as a controlled autoignition (CAI) measure in Homogeneous Charge Compression Ignition (HCCI) engines. A well validated spray combustion model can provide a good modeling tool which can facilitate understanding of spray combustion physics. In this research, a spray combustion model is proposed to model low temperature combustion in internal combustion engines. The proposed model is based on the Representative Interactive Flamelet (RIF) model of Peters (2000). In addition to the original RIF model, the effect of spray and vaporization of droplets in the reaction space were considered to be included in the governing equations as source terms. The effect of such source terms were examined in the reaction space in idealized control volumes, where the effect of vaporization is assumed as gaseous fuel addition with known rate of addition. It was found that the effect of spray may not be negligible when fuel addition occurs over a reaction space with chemical reaction. The proposed model was validated by comparing pressure and fuel concentration against experimental data from the rapid compression machine experiment of Akiyama et al. (1998) and the diesel engine experiment of Hong et al. (2008). Predictions showed good agreement with the experimental observations. Comparison between numerical models, one with spray source terms and the other without them has been carried out to examine the effect of spray source terms on spatial fuel distributions and overall pressure histories. The proposed model has been implemented in KIVA3v. The proposed model is applied to investigate the effect of stratification under PPCI operating condition using direct injection. An experimental study on the effect of stratification on combustion and emission has been numerically reproduced. The numerical results showed good qualitative agreement with the measured engine performance and emission trend against the experimental data. Detailed analysis of the in–cylinder combustion is also provided. Advisors/Committee Members: Assanis, Dionissios N. (committee member), Im, Hong G. (committee member), Babajimopoulos, Aristotelis (committee member), Driscoll, James F. (committee member).

Subjects/Keywords: Internal Combustion Engine; Combustion Model; Homogeneous Charge Compression Ignition; Mechanical Engineering; Engineering

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

APA (6^th Edition):

Keum, S. H. (2009). An Improved Representative Interactive Flamelet Model Accounting for Evaporation Effect in Reaction Space (RIF-ER). (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/62293

Chicago Manual of Style (16^th Edition):

Keum, Seung Hwan. “An Improved Representative Interactive Flamelet Model Accounting for Evaporation Effect in Reaction Space (RIF-ER).” 2009. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/62293.

MLA Handbook (7^th Edition):

Keum, Seung Hwan. “An Improved Representative Interactive Flamelet Model Accounting for Evaporation Effect in Reaction Space (RIF-ER).” 2009. Web. 11 Apr 2021.

Vancouver:

Keum SH. An Improved Representative Interactive Flamelet Model Accounting for Evaporation Effect in Reaction Space (RIF-ER). [Internet] [Doctoral dissertation]. University of Michigan; 2009. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/62293.

Council of Science Editors:

Keum SH. An Improved Representative Interactive Flamelet Model Accounting for Evaporation Effect in Reaction Space (RIF-ER). [Doctoral Dissertation]. University of Michigan; 2009. Available from: http://hdl.handle.net/2027.42/62293

University of Michigan

20. Holman, Timothy Dean. Numerical Investigation of the Effects of Continuum Breakdown on Hypersonic Vehicle Surface Properties.

Degree: PhD, Aerospace Engineering, 2010, University of Michigan

URL: http://hdl.handle.net/2027.42/77715

► A hypersonic vehicle crosses many regimes, from rarefied to continuum, as the vehicle descends through the atmosphere. This variation makes it difficult to simulate the… (more)

▼ A hypersonic vehicle crosses many regimes, from rarefied to continuum, as the vehicle descends through the atmosphere. This variation makes it difficult to simulate the flow since the physical accuracy of computational fluid dynamics (CFD) can breakdown in rarefied flows and the direct simulation Monte Carlo (DSMC) method is computationally expensive in continuum flows. This dissertation investigates the effects of continuum breakdown on the surface aerothermodynamic properties of a hypersonic vehicle. The study begins by investigating a sphere in Mach 10, 25, and 45 flow of non-reacting nitrogen gas. The consideration of nitrogen gas allows the study of the effects of thermal nonequilibrium. The next portion of the study investigates a sphere in Mach 25 reacting flows of both nitrogen and air. This adds multi-species flow to the simulation and permits for reacting flow, which allows the study of the effects of thermal and chemical nonequilibrium. A separate rotational energy equation is employed in the CFD method to be able to simulate rotational nonequilibrium. Since CFD is numerically more efficient than DSMC, slip boundary conditions are included into the CFD method to extend the range where CFD can be accurately utilized. An investigation of other physical models in both numerical methods is conducted to ensure they are equivalent. In a flow of nitrogen, as the global Knudsen number is increased from continuum flow to a rarefied gas, the amount of continuum breakdown seen in the flow and on the surface increases. This causes an increase in the differences between CFD and DSMC. As the Mach number increases, the amount of continuum breakdown observed increases. However, the difference between CFD and DSMC remains relatively constant. The differences in the surface properties between CFD and DSMC increase when the simulation is run axisymmetrically in comparison to two-dimensional. It is also seen that chemically reacting flow causes the integrated drag to increase, while it decreases the peak heating. Reacting flow is also seen to decrease the amount of continuum breakdown in the flow field. Advisors/Committee Members: Boyd, Iain D. (committee member), Im, Hong G. (committee member), Powell, Kenneth G. (committee member), Wright, Michael J. (committee member).

Subjects/Keywords: Continuum Breakdown; Hypersonic Aerothermodynamics; Computational Fluid Dynamics; Direct Simulation Monter Carlo Method; Gradient Length Local Knudsen Number; Slip Boundary Conditions; Aerospace Engineering; Engineering

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

APA (6^th Edition):

Holman, T. D. (2010). Numerical Investigation of the Effects of Continuum Breakdown on Hypersonic Vehicle Surface Properties. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/77715

Chicago Manual of Style (16^th Edition):

Holman, Timothy Dean. “Numerical Investigation of the Effects of Continuum Breakdown on Hypersonic Vehicle Surface Properties.” 2010. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/77715.

MLA Handbook (7^th Edition):

Holman, Timothy Dean. “Numerical Investigation of the Effects of Continuum Breakdown on Hypersonic Vehicle Surface Properties.” 2010. Web. 11 Apr 2021.

Vancouver:

Holman TD. Numerical Investigation of the Effects of Continuum Breakdown on Hypersonic Vehicle Surface Properties. [Internet] [Doctoral dissertation]. University of Michigan; 2010. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/77715.

Council of Science Editors:

Holman TD. Numerical Investigation of the Effects of Continuum Breakdown on Hypersonic Vehicle Surface Properties. [Doctoral Dissertation]. University of Michigan; 2010. Available from: http://hdl.handle.net/2027.42/77715

Open Access Theses and Dissertations