Abstract The speed of Electro-Hydrostatic Actuator (EHA) pump can recently reach a maximum of 20,000 rpm due to its high power density requirements. The thermodynamics of EHA pumps become increasingly important because the oil in the casing is used to cooling the high speed electric motor and solving the “hot spots” problem in the EHA system. In order to realize the boundary condition for the motor cooling at high speeds, more investigations should be given to the churning losses in terms of the large centrifugal forces of piston/cylinder assemblies and high fluid kinetic energy in high-speed conditions. This paper analyzes the influence of churning losses on the thermal-hydraulic model. Using the control volume method, heat transfer analysis of the piston pump is presented and the heat flow inside the piston pump produced by churning losses is described in details. The steady-state leakage temperatures of the high-speed EHA pump are simulated and validated through experiments. The experimental results show that the churning power losses need to be considered on the thermal-hydraulic model to ensure good performance for the prediction of the leakage temperature in EHA pump.

中文翻译：

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高速电动静液执行泵热工水力模型的搅动损失分析

摘要 由于其高功率密度要求，EHA 泵的速度最近可以达到 20,000 rpm 的最大值。EHA 泵的热力学变得越来越重要，因为套管中的油用于冷却高速电动机并解决 EHA 系统中的“热点”问题。为了实现电机高速冷却的边界条件，应更多地研究高速条件下活塞/气缸组件离心力大和流体动能高的搅拌损失。本文分析了搅动损失对热工水力模型的影响。使用控制音量方法，介绍了柱塞泵的传热分析，详细描述了搅拌损失在柱塞泵内部产生的热流。通过实验对高速EHA泵的稳态泄漏温度进行了模拟和验证。实验结果表明，需要在热工水力模型上考虑搅拌功率损失，以确保对 EHA 泵泄漏温度的预测具有良好的性能。