中文摘要：

以低速大扭矩水压马达为研究对象，应用动网格及其UDF（用户自定义函数）编程技术模拟配流盘、转子和柱塞的运动，并对水压马达模型及加入阻尼槽的模型进行了三维数值模拟计算。基于最小过流面积公式及压力变化公式，建立了不同渗透角下柱塞腔中压力变化的数学模型。研究表明：原模型柱塞腔内会出现明显的压力超凋、压力振荡、压力冲击以及速度的突变，而改进后的柱塞腔内部流场变化比较平稳，可以有效地降低配流过程中产生的冲击，降低压力飞升现象，减小振荡幅值和时间，实现了预升压的目的。同时还发现阻尼槽的渗透角越大，预升压效果越明显。

英文摘要：

Taking low speed high torque water hydraulic motor as the main research object, the movement of port plate, rotor and piston were simulated by the dynamic mesh technique and UDF （user defined function） in Fluent. And 3-D internal flow field of water hydraulic motor and the model with damping groove were computed numerically. Based on the minimum through-flow area equation and the formula of pressure change, the mathematical model of the pressure of plunger cavity was established at various percolation angles. The research showed that the original model of plunger cavity had significant pressure overshoot, pressure oscillation, pressure surge, and velocity jump. When the model was modified, the internal flow field of plunger cavity became more stable, so that the shock in valve port process could be effectively reduced and the phenomenon of pressure rise was reduced and the oscillation amplitude and time were decreased. The aim of pre-loading were well achieved. It was also found that the larger the percolation angle of damping groove was, the more effective the pre-loading was. The research could be an important reference for port plate optimal design.