3-D Numerical study on the effect of variant injection pressure in a diesel injector with cavitation formation

Wei Liu, Jizhong Zhao


The aim of current study was to explore the multi-phase flow of the diesel fuel and vapor initiation in the nozzle segment of a diesel injector. In this research project, the injection pressure on the injector is varied in two levels of 50 MPa and 75 MPa, while the discharge pressure is kept constant. The key feature of nozzle simulation is laid in increasing pressure drop as the injection pressure is increased. It is revealed, however, that with increasing the injection pressure, the cavitation formation is intensified and more fuel vapour is present at the nozzle entrance. The discharge coefficient from nozzle exit when the flow is stabilized reaches to 8.59×10-7 for P = 50 MPa (CD =8.59×10-7), while for injection pressure of 75 MPa a lower discharge is maintained equal to CD = 7.408×10-7. The contour plots of two different cases under study are presented, compared and commented upon in terms of volume fraction, velocity, and Turbulent Kinetic Energy (TKE). The flow variation with respect to important in-nozzle quantities are discussed as well. 

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