多喷孔活塞式调流调压阀空化流动特性分析

以DN200多喷孔活塞式调流调压阀为研究对象，基于数值模拟，结合Realizable k-ε湍流模型和Zwart-Gerber-Belamri空化模型，研究了小开度、中等开度和大开度下空化流动特性以及节流孔内空化的形成机制，并且分析了开度和空化数对空化流动的影响。结果表明，节流孔处存在较大的压力和流速梯度，节流孔进口边缘附近会出现流动分离，在节流孔壁面形成附壁剪切旋涡，流动分离和附壁剪切旋涡是节流孔内空化的形成机制。同时，固定阀门进出口压力，随着开度逐渐增大，空泡体积线性增加，各开度空化强度相差不大。另外，随着空化数逐渐减小，流量系数呈现出先保持稳定后略微增加再急剧减小的变化趋势。本研究结果可以为该类型阀门的结构优化与运行维护提供参考。

Cavitating flow characteristic analysis of flow and pressureregulating valve with piston

This paper presents a study of a flow and pressure regulating valve of DN200 type,using numerical modeling that combines a realizable k-εturbulence model with a Zwart-Gerber-Belamri cavitation model.We focus on the cavitating characteristics of flows in the valve with small,medium and large openings,and the effects of valve opening and inlet-outlet pressure difference on these characteristics.The results show that high pressure and large velocity gradients occur in the orifice,flow separation appears near its inlet edge,and wall attaching shear vortices form at the wall.Flow separation and generation of these vortices are the mechanism of flow cavitating in the orifice.Under fixed inlet and outlet pressures,the total volume of cavitation bubbles increases linearly with valve opening,while cavitation strength varies insignificantly.As the cavitation coefficient is decreasing,the flow coefficient keeps stable first, then increases slightly, but decreases sharply after that. The results are useful for thestructural optimization and operation maintenance of DN200 valves.