| The injector nozzle in diesel engine that is the terminal of the injection system has a decisive impact on the quality of atomization, the cooperation of oil beam and combustion chamber, the length of fuel injection duration and a direct impact on the quality of combustion in the cylinder. The spray quality is an important factor of affecting diesel engine performance. Good atomization is not only to improve the dynamic performance of diesel engines but also to reduce harmful emissions and improve the economy of fuel. The spray characteristic is closely related to the fuel flow in an injector nozzle. With the increase of injection pressure, the cavitation occurs easily in an injector nozzle. Cavitation generation, on the one hand, increases the turbulence flow and atomization capabilities, on the other hand reduces the flow efficiency and erodes the inner surface of the fuel injector nozzle, which affect the life of an injector nozzle, the atomization effect and the whole performance of an engine. Therefore, it is necessary to do an in-depth study of the cavitation flow in an injector nozzle.In this paper, the research object is the injector nozzle of diesel engine. Based on the computational fluid dynamics methods, the fluid dynamics software is used to establish a three-dimensional grid model of the injector nozzles and do the numerical simulation on cavitation flow in the diesel engine injector nozzle. And the simulation results are done a comparative analysis. In the simulation process, a single-fluid model and a multi-fluid model are established respectively and the single-hole injector and the multi-hole injector are simulated. The pressure distribution, velocity distribution, cavitation distribution and flow flux are analyzed. The results of different models and different injector nozzles are compared. The simulation results provide the directive direction on the design and improvement of diesel engine fuel injector nozzles and a boundary condition for the spray simulation.
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