Date of Award
Summer 2019
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Mechanical Engineering
First Advisor
Roy, Somesh P.
Second Advisor
Singer, Simcha
Third Advisor
Borg, John
Abstract
Soot formation is a complex process and the actual soot formation methodology is still a mystery. Numerically modeling of soot requires successful coupling of turbulence, chemistry and radiation modeling. In the present study, a comprehensive sensitivity study is conducted to see the effect of radiation and exhaust gas recirculation (EGR) on soot and NOX formation in a high pressure spray combustion scenario. The spray-A case (n-dodecane as fuel) from Engine Combustion Network (ECN) is used as the target condition. Two different soot modeling approaches have been considered: a semi-empirical two-equation model and a method of moments with interpolative closure (MOMIC). A multiphase photon Monte Carlo (PMC) solver with line-by-line (LBL) spectral database is used to resolve radiative heat transfer. Results show that, effect of radiation on soot is minimal in spray-A configuration. Inclusion of radiation modeling, on the other hand, marginally reduce NO prediction. Both peak soot and NO formation increases with O2 content in EGR. Oxygen content of EGR is found to have significant effect on soot sizes as the mean soot diameter increases along with considerable widening of the diameter distribution with the increase of O2 percentage.