A numerical study of cavitating flows in high-pressure diesel injection nozzle holes using a two-fluid model

Cavitating flows inside a diesel injection nozzle hole were simulated using a two-fluid model. Attention was focused on the complex cavitation processes and flow characteristics under constant inlet pressure and fluctuant inlet pressure modes. To validate the two-fluid model, model predictions were compared with the experimental data available in the literatures, and good agreement was achieved. The numerical results show that the appearance of supercavitation in the diesel nozzle hole induces obvious changes of flow field structures and exit flow conditions. The distributions of liquid phase turbulent kinetic energy and exit velocity profiles corresponding to the supercavitation regime indicate the potential for promoting the primary breakup of a diesel jet. Furthermore, the upstream pressure fluctuations significantly influence the cavitation processes. Both partial cavitation and supercavitation show unsteady behaviors as the rapid rise or fall of upstream pressure. Supported by the National Natural Science Foundation of China, Key Project Funding (Grant No. 50636040) and Major State Basic Research Development Program (Grant No. 2007CB210001)