结构尺寸对二级节流阀空化流动特性的影响

摘要

The shape and structural sizes of throttle valve port have a direct impact on the characteristics of cavitating flows in a two-step throttle,so it is important to choose and design the right form of the throttle valve port. Here,the effects of different port sizes on cavitation flow field,flow velocity and cavitation area in a throttle valve were investigated using CFD to choose the best combination of port sizes and choke sizes.The numerical results showed that there are four vortexes located at upstream of the flow channel,the wall of the middle section of two-port valves,the top of valve rod,and downstream of the flow channel;with the change of port size of m and n,the positions of vortex in a two-step valve are almost the same,but their areas change;however,if m =2,n =1,the two-step throttle valve has a better structure with an anti-cavitation performance.The results provided a theoretical basis for engineers to design a high-performance throttle valve.%节流阀口的形式以及结构尺寸直接影响节流阀的性能，因此阀口结构形式选择及其设计是很重要的。通过数值模拟的方法研究了二级节流口尺寸不同对阀内空化流场、流速以及空化区域的影响。研究结果表明：二级节流阀内上游腔的拐角处、二级节流口中间腔的近壁面区域、阀芯的顶部、节流口下游的近壁面区域存在四个回流区。随着阀口尺寸 m、n 的改变，阀内回流区位置几乎不变，但是回流区面积大小会发生改变。但是 m ＝2，n ＝1时二级节流阀具有较好的抗空蚀特性。研究结论为工程人员设计高性能液压阀提供了理论依据。