高温高压差液控阀空化和空蚀的数值分析

摘要

采用高温高压液控阀的实际操作条件和介质的物性参数,基于两相空化流动的控制方程和RNG k-ε湍流模型.对液控阀的空化和空蚀特性进行数值分析.结果表明:流体在流经阀座和阀芯之间的间隙时,流速急剧增加,压力迅速降低至液体的饱和蒸汽压以下,形成空化.由于阀芯出口处的突扩结构,流速急剧降低,产生分离现象,从而在下游出现回流区,回流区域会形成空化带.并且,当操作温度升高和入口压力增加均会导致空化的区域增大、强度增加.数值模拟结果与阀芯的实际失效形貌基本吻合,证明该方法可成功应用于阀门的空化和空蚀预测.%The cavitation erosion numerical analysis of a high temperature and large pressure decrease hydraulic valve is conducted based on the two phase cavitating flow and RNG turbulence model via the actual operating conditions and medium physical parameters.The results showed that:the velcotiy increases rapidly when the flow passes through the gap between the vlave seat and impact head,and the pressure dereases to the saturation vapor pressure which induced the formation of cavitation.For the sudden expansion structure in the outlet of valve,the velocity decrease dramatically,resulting in the fluid separaion,backflow and cavitation cloud.Besides,the increaseing of operating temperature and inlet pressure will lead to the expansion of cavitation cloud and the increasing of cavitation intensity.The numerical results are in accordance with the actual failure position,which is proved that the method can be sucessfully applied to the predicion of valve cavitation.