基于边界重构方法的双吸离心泵空化-颗粒协同侵蚀与性能衰减特性研究

Numerical Investigation of Cavitation-Particle Synergistic Erosion and Performance Degradation in Double-suction Centrifugal Pump Using Boundary Reconstruction Approach

摘要:

针对黄河高含沙水流工况下双吸离心泵叶轮渐进磨损与性能衰减问题,本文以黄河上游某提灌泵站工程泵为对象,构建基于欧拉-拉格朗日两相流、SST k-ω湍流模型、Zwart-Gerber-Belamri空化模型和E/CRC磨损模型的空化-颗粒协同侵蚀数值方法,并结合边界重构实现等效4 000 h运行过程叶片形貌动态更新及流场再分析。结果表明,高侵蚀区主要集中在压力面尾缘和叶片进口边,与高速度、高颗粒浓度及大冲击角区域相对应;随运行时间增加,进口边产生侵蚀坑,出口边钝化并形成锯齿状缺口,局部流道收缩和泄漏流增强,导致叶轮内部涡量和湍动能耗散显著提高。等效4 000 h内,泵扬程和效率分别降低约5.17%和12.17%,叶轮质量损失率约14.67%,性能演化呈缓慢"增长期-加速期-稳定期"阶段性特征,可为高含沙流域双吸离心泵抗磨设计和寿命评估提供依据。

Abstract:

Aiming to address the progressive impeller wear and performance degradation of double-suction centrifugal pumps operating under high-sediment Yellow River conditions,a prototype pump from an irrigation station in the upper Yellow River was selected as the research object. A cavitation-particle synergistic erosion numerical framework was established based on an Euler-Lagrange two-phase flow approach,the SST k-ω turbulence model,Zwart-Gerber-Belamri cavitation model,and E/CRC erosion model,which was further coupled with a boundary reconstruction strategy to realize dynamic updating of blade geometry and flow-field reanalysis over an equivalent operating time of 4 000 h. The results showed that high-erosion regions were mainly concentrated at the pressure-side trailing edge and blade leading edge,corresponding to zones of high velocity,high particle concentration and large impact angle. With increasing operating time,pits form at the leading edge,while the trailing edge became blunted and developed serrated notches,causing local passage contraction and intensified leakage flow,which in turn significantly enhanced vorticity and turbulent kinetic energy dissipation inside the impeller. Within 4 000 h of equivalent operation,the pump head and efficiency were decreased by about 5.17% and 12.17%,respectively,and the impeller mass loss ratio reached approximately 14.67%. The performance evolution exhibited a distinct "latent-accelerated-stable" three-stage pattern,providing a basis for wear-resistant design and service life assessment of double-suction centrifugal pumps in high-sediment river regions.