空化模型中的相变系数对不同头型的适用性研究

摘要

应用基于CFD的数值计算方法,研究了Zwart空化模型中的相变系数对不同头型圆柱空化问题的适用性.通过计算流线型和非流线型圆柱在不同空化数下的表面压力系数,并与实验值对比,得到不同头型圆柱空化计算时相变系数的设定规律.研究结果表明,对于流线头型的圆柱,流动分离作用很弱,应当增大蒸发系数和冷凝系数;对于非流线头型的圆柱,流动分离作用强烈,数值计算结果对相变系数变化的敏感性较低,只需保证蒸发系数和冷凝系数的数量级关系即可较准确模拟空化现象.%The applicability of the phase-change coefficients in Zwart cavitation model for different types of cylindric-al cavitation problems are studied by numerical calculation method based on computational fluid method (CFD). Phase-change coefficients setting rules are got by comparing surface pressure coefficients calculated in streamlined and non-stream-lined cylinders under different cavitation numbers with experimental data, when calculating different types of cylindrical cavitation problems. The results show that, for streamlined cylinders, evaporation coefficients and condensation coefficients should be increased due to flow separation effect is very weak. For non-streamlined cylinders, the sensitivity of numerical results for phase-change coefficients is relatively low due to flow separation effect is very strong. Only the magnitude rela-tionship between the evaporation coefficient and condensation coefficient should be ensured, and then cavitation phenomena can be simulated accurately.