The internal leakage of a radial piston motor (RPM) is an unavoidable structural characteristic, and the amount of internal leakage has a critical effect on the volumetric efficiency of the motor. Using the distribution plate as the force body, an equation for the balance between the preload spring force and the hydrodynamic force is analytically derived, the variation range of the clearance of the flow distribution pair (FDP) is determined, and a model for the internal leakage flow of the FDP is developed. Based on computational fluid dynamics (CFD) simulations, the effects of the oil film thickness, inlet pressure, motor speed, and oil temperature on the leakage volume are investigated. An efficiency test system for RPMs is built and tests are performed on motor prototypes. The experimental results show that the error between experimental and simulation results decreases gradually with increasing motor speed. When the motor runs at the rated speed, the error is stable within 5%. The experimental results verify the correctness of both the theoretical and CFD models. The CFD analysis method can be used as a technical means to optimize the motor volumetric efficiency and the preload spring design.

中文翻译：

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通过CFD分析和实验研究径向柱塞液压马达流量分配副的泄漏

径向柱塞马达（RPM）的内泄漏是不可避免的结构特征，内泄漏量对马达的容积效率有着至关重要的影响。以分配板为受力体，解析推导了预紧弹簧力与水动力的平衡方程，确定了流量分配副间隙（FDP）的变化范围，建立了内部模型开发了 FDP 的泄漏流。基于计算流体动力学（CFD）模拟，研究了油膜厚度、入口压力、电机转速和油温对泄漏量的影响。建立了转速效率测试系统，并在电机原型上进行了测试。实验结果表明，随着电机转速的增加，实验结果与仿真结果之间的误差逐渐减小。电机在额定转速下运行时，误差稳定在5%以内。实验结果验证了理论模型和CFD模型的正确性。CFD分析方法可以作为优化电机容积效率和预紧弹簧设计的技术手段。