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Numerical Simulation of Cavitation Phenomenon Under High Fuel Pressure Condition
Published May 20, 2009 by Society of Automotive Engineers of Japan in Japan
Event: JSAE Spring Conference
Direct fuel injection system is getting popular in internal combustion engines due to the superior performance in fuel economy and power. To optimize the fuel-air mixture distribution inside the cylinder, the geometry of nozzle and the mixture formation process must be well designed. To attain this, numerical simulation will be a good tool, but the prediction ability is not enough for the practical design. In this study, a two-phase flow of fuel and gas including cavitation inside an axi-symmetrical nozzle was evaluated to improve the prediction ability. Two kinds of cavitation model (quasi-steady dynamic bubble model and discrete bubble tracking model) are proposed and implemented into a commercial code FLUENT 6.4. As a result, discrete bubble tracking model could obtain converged solutions even for high differential pressure conditions between the nozzle entrance and the exit up to 6 MPa and predict the cavitation phenomenon qualitatively. Moreover, the unsteady fuel injection was calculated. As a result, the process of interface instability due to cavitation was found.