UBC Theses and Dissertations
Turbulent combustion of gas-air mixtures in a spark ignition engine Boisvert, Julie
An engine simulation model has been developed to describe turbulent combustion of gas-air mixtures in a spark-ignition engine. The model incorporates a turbulent entrainment combustion theory proposed by Daneshyar and Hill which is based on Tennekes' model of turbulence and the vortex bursting principle of Chomiak. Flame propagation was based on turbulent entrainment. The flame was modelled as a thick spherical shell composed of burned and unburned gases. Inside the thick flame, pockets of initial size A, the Taylor microscale, are consumed at a rate of the order of the laminar burning velocity. To compare the model to experimental data, turbulence levels were measured in a motored Ricardo Hydra engine using hot wire anemometry. Combustion pressure data were measured with a piezoelectric transducer. Results indicate that the model is successful in predicting trends in overall combustion rates when the engine speed and air-fuel ratio are varied. The model also provided insight into the structure of turbulent flames in engines.
Item Citations and Data