Experimental and Numerical Simulation of Cavitating Flows in Liquid Nitrogen

The experiment and numerical simulation are both performed to investigate the characteristics of unsteady cavitating flows in liquid nitrogen. The experiment was conducted in the cryogenic cavitating flows test platform and a high-speed video camera was employed to obtain the unsteady evolution of cavitating flows through the convergent-divergent nozzle. In addition, the pressure distributions at cavitation region and the flow rate were collected synchronously. The large-eddy simulation (LES) and the density-corrected turbulence model (DCM) were used respectively to calculate the unsteady cavitating flows. The experiment results show that the unsteady characteristics of liquid nitrogen cavitating flows are significant. The complete shedding cycle of the cloud cavity is about 3 ms and the cavity structure is indistinct and hard to collapse. Due to the thermodynamic effects, the measured pressure at cavity region is lower than that of free-stream liquid. The numerical results show that the predicted cavity structure, the quasi-periodic characteristics of cavitation and pressure inside cavity by two turbulence model agrees well with the experimental data. Compared with the results calculated by large-eddy simulation, the shedding cloud cavity predicted by DCM model is larger and the cavity interface is clearer. The cavity structure simulated by LES is indistinct, which agrees well with the experimental observation.