A Stochastic Model of Turbulent Mixing with Chemical Reaction: Combustion Period of an Internal Combustion Engine.

A model for predicting the burnrate of a premixed and stratified internal combustion engine is developed. The burnrate model is composed of the ignition period dominated by molecular and turbulent diffusion and the combustion period dominated by turbulent diffusion. A correlation for the ignition period based on a deterministic model for the structure of turbulence is used; this correlation uses turbulent characteristics and the laminar flame speed. A statistical model employing a Monte Carlo technique to follow the mixing process is developed to describe the combustion period; the mixing process is based on turbulent characteristics. The model is used to predict the effects of varying the spark advance, adding exhaust gas recirculation, and the variable stroke of a non-swirling premixed engine; the effects of stratification are explored. The model predictions of the burnrate show the correct trend for variation in spark advance, for adding exhaust gas recirculation, and the variable stroke engine. With increased mixture stratification, the model predicts a reduction in available work. The trends in the model predictions are verified by experimental data. Effects of spark advance, exhaust gas recirculation, and variable stroke engine for a premixed charge are presented.Ph.D.Automotive engineeringUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/158881/1/8215050.pd