Ph.D. Proposal

Shubham B. Karpe  

(Advisor: Prof. Suresh Menon) 

"Role of Gas-phase Kinetics, Turbulence-chemistry Interactions, and Model 
Sensitivities in Soot Observable Processes" 

 
Friday, April 14 

2:30 p.m.  

Montgomery Knight Building 317 

Abstract 

Stringent government regulations regarding the emissions of non-volatile particulate matter (nVPM) have motivated efforts to better predict soot formation and growth in a practical gas turbine engine. Reliable numerical methodologies can be a viable tool here but predicting soot numerically is an inherently complex problem that is further aggravated by the presence of the multiscale and multi-physics nature of soot-turbulence-chemistry interactions in a turbulent environment. Moreover, the current understanding of soot formation and growth is crippled with major uncertainties at each stage of soot formation and growth starting from its nucleation, and surface growth, to aggregation, etc. The purpose of this research is to understand key factors influencing soot formation and growth in turbulent reacting flows in a systematic manner from canonical to complex flows. First, zero-dimensional perfectly stirred reactors are used to establish the role of gas phase kinetics and key model sensitivities (sizes, and concentrations of inception species as well as rates of coagulation and surface growth for soot particles) on global soot predictions as well as soot particle size distribution functions. To simulate complex three-dimensional turbulent reacting flows, a multi-scale and multi-physics Linear Eddy Mixing (LEM) model, that takes into account the reaction, diffusion, and turbulent stochastic stirring at their respective scales within the subgrid of Large Eddy Simulations (LES), is extended to account for soot physics. It will be used to conduct simulations of the sooting turbulent bluff body stabilized flames of gaseous ethylene fuels for verification against the experimental data. Furthermore, this verified LEMLES based modeling framework will be used to assess the impact of model sensitivities such as the stages of nucleation, surface growth, and fractal evolution on a more canonical non-premixed temporal mixing jet. Eventually, model simulations of soot formation and growth will be shown in a more complex liquid fueled Rich-Burn-Quick-Quench-Lean-Burn (RQL) gas turbine combustor while acknowledging key understandings of its sensitivities. 

Committee

•    Prof. Suresh Menon    –   School of Aerospace Engineering (advisor)

•    Prof. Adam Steinberg  –  School of Aerospace Engineering

•    Prof. Joseph Oefelein  –  School of Aerospace Engineering

•    Prof. Wenting Sun       –  School of Aerospace Engineering

•    Prof. Michael Mueller  –  School of Mechanical and Aerospace Engineering, Princeton University