Effects of structural sizes on characteristics of cavitating flows in a two-step throttle valve

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 twostep 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 highperformance throttle valve.