基于重叠网格技术的并联泵系统止回阀关闭过程特性研究

Parallel pump systems are widely used in many industries, including municipal water supply and drainage systems, chemical industries, power systems and irrigation systems. Check valves are essential components to prevent reverse flow in parallel pump systems. High pressure surges induced by the sudden closure of check valves can cause severe damage to mechanical and hydraulic facilities. Therefore, it is essential to study the behavior of closure of check valves in parallel pump systems. Yet, the dynamic behavior of check valve closure in parallel pump systems remains unclear and requires further investigation. . This project focuses on the dynamic behavior of check valve closure in parallel pump systems. Numerical and experimental investigation are performed to study the flow development and the mechanism of pressure surges during check valve closure. A three-dimensional unsteady numerical simulation of a dual disc check valve closure induced by upstream pump shutdown and by main pipe control valve closure are performed and validated experimentally. An overset mesh was applied to achieve a full closure of the check valve discs and capture pressure surges accurately. The dynamic fluid-body interaction technology is applied to compute the fluid-induced force and torque on the check valve discs. The flow filed and pressure surge improve the understanding of the flow field evolution during the transient event. The impact of system outlet pressure, initial flow rate, and pump shutdown speed on pressure surges was investigated to explore factors that affect the amplitude of pressure surges. This work improves the understanding of check valve closure behavior, which is beneficial to check valve design, selection, and operation. Additionally, this work proves that overset mesh technology could be applied to other similar flow domain breaking cases. Also, the findings of this project can be further developed to contribute to stability analysis of parallel pump systems.

并联泵系统广泛应用于工业生产中，而止回阀是其中关键部件。申请人在前期研究中发现，止回阀的关闭过程可能引发剧烈的压力脉动，造成严重后果。但对于并联泵系统，止回阀在关闭过程中的动态行为及流场细节仍亟需明确，也是有待深入研究的基础问题。本项目立足于工程实际需要，从系统层面上研究并联泵系统内止回阀的关闭过程，通过全三维数值模拟与实验相结合的方法，揭示瞬态流动演化规律和瞬态压力脉动产生的机制，并探讨影响压力脉动强度的因素。为解决数值模拟中常见的动网格技术无法实现止回阀完全关死而造成的压力捕捉不准确问题，本项目拟采用重叠网格技术实现止回阀的完全关死，并结合动态流固耦合技术准确计算流体对止回阀阀片的力与力矩。本项目还重点分析泵停机主管路控制阀关闭诱发的止回阀关闭过程的压力脉动产生机制和影响因素。本项目研究成果将为并联泵系统止回阀的设计、选型、维护提供指导，并为并联泵系统的可靠性分析研究提供支撑。

并联泵系统广泛应用于工业生产中，而止回阀是其中关键部件。申请人在前期研究中发现，止回阀的关闭过程可能引发剧烈的压力脉动，造成严重后果。但对于并联泵系统，止回阀在关闭过程中的动态行为及流场细节仍亟需明确，也是有待深入研究的基础问题。本项目立足于工程实际需要，从系统层面上研究并联泵系统内止回阀的关闭过程，通过全三维数值模拟与实验相结合的方法，揭示了瞬态流动演化规律和瞬态压力脉动产生的机制，并探讨了影响压力脉动强度的因素。为解决数值模拟中常见的动网格技术无法实现止回阀完全关死而造成的压力捕捉不准确问题，本项目采用了重叠网格技术实现止回阀的在CFD数值仿真过程中 的完全关死，并结合动态流固耦合技术准确计算了流体对止回阀阀片的力与力矩。本项目还重点分析了泵停机主管路控制阀关闭诱发的止回阀关闭过程的压力脉动产生机制和影响因素。研究结果表明，重叠网格技术在止回阀关闭过程的CFD数值模拟过程中可以实现止回阀的完全关死，从而准确捕捉到阀片关死产生的压力脉动；在止回阀关闭过程中，停泵速度是影响并联泵系统止回阀关闭过程中压力脉动的最主要影响因素。本项目研究成果为并联泵系统止回阀的设计、选型、运行维护提供指导，并为并联泵系统的可靠性分析研究提供支撑；同时，本项目的研究也表明，重叠网格在类似的涉流体的刚体运动仿真中可以发挥重要作用。在本项目的启发下，我们将重叠网格技术用于空调四通换向阀的换向过程流场仿真，成功指导了空调四通换向阀的减振降噪优化设计。

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