不同流体介质的空化热力学效应

In order to analyze the thermal effect in different liquids, the computations are conducted in water, nitrogen and hydrogen with different temperatures by numerical methods. The computations based on the homogenous multiphase model are conducted around a hydrofoil for three temperatures by implementing FBM turbulence model, which can describe the unsteady cavitation characteristics more exactly and the revised cavitation model considering the thermal effect. The energy equation considers the cavitation influence in the source term. The numerical models and the variable thermal properties of the fluid are implemented with software. The results show that for water, nitrogen and hydrogen, the thermal effect becomes increasingly obvious, and in the same fluid, the thermal effect is more significant when the operational temperature is near to the critical point. The thermal effect is obviously shown in a shorter cavity length, a more decreased vapour volume fraction and a more distinct pressure and temperature depression. The material properties decide the intensity of the thermal effect on cavitation, the influence material parameters include the saturated vapor pressure, the liquid/vapour density ratio and the thermal conductivity. When the gradient of saturation vapor pressure is larger, the liquid/vapour density ratio and the thermal conductivity decrease, so the thermal effect for this liquid or the operational temperature range is more obvious.