不同空化程度下离心泵流固耦合特性研究

摘要

For fluid-structure interaction problems of a centrifugal pump under cavitations,a centrifugal pump's cavitation was simulated numerically based on a full cavitation model and a gas-liquid two-phase model.The deformation of the pump rotor system was simulated under different cavitation levels using the one-way coupling calculation method. Cavitation bubbles on the impeller,static pressure,liquid relative velocity distribution,pressure pulsation in the volute and impeller radial force characteristics were analyzed.The effects on the internal flow field of the pump and its rotor system deformations were studied.The results showed that the bubble volume and bubble area on blade suction surface are larger than those on blade pressure surface;impeller static pressure distribution is more uneven with cavitation development;the bubbles on the impeller block the flow channel under serious cavitation,and cause the flow separation phenomenon,then vortexes appear;cavitation leads to increase in pressure fluctuation in the volute and irregular distribution of radial force;cavitation affects the deformation of a centrifugal pump rotor system,the non-axisymmetric deformation of the impeller is caused by vortexes generated from cavitation.%针对离心泵空化下流固耦合问题，采用完全空化和气液两相模型，对离心泵空化进行了数值模拟计算，结合单向耦合计算方法求解了不同空化程度下转子系统的变形。分析了空化时叶轮上气泡、静压、液体相对速度分布情况以及蜗壳内部压力脉动和叶轮径向力特性，研究空化对离心泵内部流场和对转子系统变形的影响。结果表明，叶片吸力面较压力面的气泡体积和气泡区更大；随着空化的发展叶轮静压分布越不均匀；严重空化时叶轮上的气泡会堵塞流道，引起脱流现象，生成漩涡；空化导致压力脉动增强，径向力分布不规律；空化影响了离心泵转子系统的变形，空化引起的漩涡造成叶轮非轴对称变形。