The Gasoline Combustion Model Based On The Fractal Characteristic Of Flames

The numerical simulation of the internal combustion engine has supplied powerful support to the research on working process of the internal combustion engine. The quasi-dimension model has widely applied range because of the connection between the thermodynamics process and in cylinder turbulence. The fractal theory which is a kind of nature theory has provided an analysis method on the complex phenomenon .The turbulence and premixed turbulent flame just contain the fractal idea. Therefore,it is possible to take fractal theory to describe the evolution of the premixed turbulent flame and the fractal theory is also introduced to analyze the combustion process in the quasi-dimension model.This paper has taken the premixed mixed turbulent flame by the high-speed camera on the combustion visualization engine that is modified from a product engine. The fractal dimension has attained by the image processing. The BOOST quasi-dimension model has been checked by the fractal dimension and in cylinder pressure data.The fractal dimension and combustion process with different working condition has been researched by the BOOST simulation based on the fractal combustion model. The results have shown that:The higher gasoline speed could cause the reduction of the volumetric and IMEP of the gasoline. But the fraction dimension has risen because of the high turbulent intensity resulted from the high speed of the gasoline. The simulation results with different air-fuel ratio have shown that the combustion process with lower air-fuel ratio has higher fractal dimension because the more fuel particles in the unit space could bring more obvious influences on the combustion flame structure. The advanced ignition timing could result in higher fractal dimension because of the advanced combustion phase and stronger turbulent motion. The model could predict the performance characterize of the engine.Therefore,the BOOST quasi-dimension model could accurately predict the working process of the engine which would play guidance role on the experiment.