空化初生, 喷嘴, 数值模拟, 流体物性

This paper investigated the effects of fluid characteristics and orifice geometry on cavitation inception in orifice. A full cavitation model was implemented in case of the fluids with different properties (viscosity, vapor pressure and surface tension) and the orifice with different geometries (inlet radius and length-to-radius (L/d) ratio). The formation and development of cavitation inside the orifice were analyzed quantitatively based on both parameters of critical cavitation pressure and critical cavitation number. According to the numerical simulation, it is revealed that the critical cavitation pressure increases with the increase of fluid viscosity and the decrease of vapor pressure of fluid. But the surface tension of fluid has not relative with cavitation inception. The critical cavitation pressure also increases with inlet radius and length-to-radius ratio. In case of fluids with same viscosity and same orifice, the critical cavitation number has little variation, though the critical cavitation pressure would change with variation of vapor pressure of fluids. Both of critical cavitation pressure and critical cavitation number change from the variations of frictional loss between the wall and fluids, flow direction due to different geometries of orifice; and from the continuity variation in-side fluids due to the variation of fluid properties.