考虑空化效应的离心泵叶轮水力激振流固耦合机理研究

The key hydraulic equipment in energy field has presented the trend of high speed, high temperature and high pressure, and the cavitation issue and the induced structural vibration is more and more urgent, which is closely related to the stability and safety reliability of these key equipment systems. Based on this, the aim of this project is to address the fluid-structure interaction mechanism of hydraulic vibration considering the cavitation effect, and the impeller of a centrifugal pump is employed for analyses. The following issues will be included in the present project: (1) Establishing a CFD model of centrifugal pump for cavitation transient flow based on PANS model and Zwart-Gerber-Belamri cavitation model, and clarifying the evolution behavior of the cavitation and unsteady flow characteristics of the impeller with cavitation; (2) Establishing a bidirectional fluid-solid coupling model for transient dynamic analysis of the impeller considering the cavitation transient flow based on a MFX coupled solver, and analyzing the key parameters influencing the stability and precision of the model; (3) Clarifying the influence of the cavitation turbulent flow on the vibration characteristics of the impeller using the above fluid-structure coupling model and revealing vibration mechanism for the impeller of centrifugal pump under cavitation transient hydraulic excitation. This project is expected to provide new theoretical basis for the cavitation-structure interaction analysis and to give scientific support to the reliability design for hydraulic machineries.

随着能源领域重大水力装备不断向高速、高温和高压方向发展，空化与其诱导结构振动的问题研究愈加迫切，关乎着重大装备系统的稳定性和安全可靠性。基于此，本项目以离心泵叶轮为对象，开展考虑空化效应的离心泵叶轮水力激振流固耦合机理研究。主要包括：（1）基于PANS模型和Zwart-Gerber-Belamri空化模型，建立离心泵空化流动的计算流体力学模型，阐明离心泵叶轮空化形态演化行为及其非定常流动特性；（2）基于MFX多场耦合求解器，建立考虑空化湍流效应的离心泵叶轮双向流固耦合求解模型，明确影响流固耦合求解精度和稳定性的关键参数；（3）基于上述建立的流固耦合计算模型，澄清空化湍流对离心泵叶轮振动特性的影响规律，揭示离心泵叶轮在空化瞬态水力激振作用下的振动响应机理。本项目的研究，有望为空化作用下流体机械水力激振规律及流固耦合机理的研究提供新的理论依据，为水力机械部件的可靠性设计提供科学支持。

随着能源领域重大水力装备不断向高速、高温和高压方向发展，空化与其诱导结构振动的问题研究愈加迫切，关乎着重大装备系统的稳定性和安全可靠性。对于离心泵叶轮空化流动而言，现有研究在空化形态预估、流固耦合计算模型、流固耦合振动机理方面仍在发展阶段。基于此，本项目以离心泵叶轮空化为研究对象，综合运用理论分析、数值模拟、实验研究的方法，开展了空化作用下离心泵叶轮流固耦合振动机理的研究。主要内容包括：①基于Zwart-Gerber-Belamri空化模型建立了离心泵空化两相流动的计算流体力学模型，开展了空化模型关键参数对的影响研究，系统性的阐明了空化形态、压力脉动、径向力等离心泵叶轮空化非定常流动特性；②基于MFX多场耦合求解器，建立了考虑空化的离心泵叶轮流固耦合计算模型，结合离心泵压力脉动、气蚀特性等实验数据，明确了影响流固耦合求解精度和稳定性的关键参数；同时考虑流体介质的可压缩性，开展了预应力作用下离心泵叶轮的干、湿模态分析，研究了不同气液比状态对离心泵叶轮的固有频率及其附加质量的影响，初步探究了离心泵叶轮振动响应的根源；③结合离心泵的汽蚀特性曲线，研究了不同空化数下离心泵叶轮的流固耦合振动特性，阐明叶轮在不同空化状态下的振动响应规律；开展了空化形态、压力脉动和叶轮动应力的关联对比研究，探究了离心泵叶轮空化诱导结构振动响应的机理。项目执行期间，发表论文5篇，其中SCI刊源论文3篇；申请发明专利1项。项目组晋升高级职称1人，培养硕士研究生4名。