本文通过数值分析研究了不同开度的稳态工况及启、闭过程的瞬态工况，对活塞式调节阀的水力特性进行了全面分析。求得调节阀的流量系数、流阻系数、汽蚀系数等随开度变化的特性参数曲线，并对比活塞阀芯在启闭过程的动态液动力，以及对阀内流场分布进行综合探讨。活塞式调节阀具有较好的流量线性特性，且只在较小开度下有明显流阻，开度增大后流阻迅速减小而保持较低的过流损失。本次研究工况范围内最小汽蚀系数为40.3，应确保调节阀的允许汽蚀系数小于该值。阀门的流开型结构使阀芯轴向的启闭液动力均作用于开阀方向，且开阀力小于关阀力。另外，对比了不同开度的阀内流速、流线、压力和湍动能等流场分布来对该活塞式调节阀的流动特性进行说明。

To analyze the hydraulic characteristics of piston control valve in detail, steady-state conditions in different openings as well as transient conditions during opening and closing were investigated by numerical analysis. Curves of the flow coefficient, resistance coefficient and cavitation coefficient were obtained. Dynamic flow forces acted on the piston spool were compared while the valve opened and closed. And the flow field distribution was discussed as well. The flow characteristics of the valve is linear. The flow resistance is obviously only in small opening but it will decline rapidly with the increase of valve opening and the head loss will stay low thereafter. The minimum cavitation coefficient is 40.2 in this investigation, indicating that the allowable cavitation coefficient of piston control valve should be less than this value. As the fluid flow leads to opening tendency in this valve structure, both of the flow forces during valve opening and closing act in the open direction, and the former is less than the latter. In addition, flow field distributions of velocity, streamline, pressure and turbulent kinetic energy in different openings were studied to illustrate flow characteristics of the piston control valve.