轴流泵空化流及其诱导压力脉动的数值模拟  

Numerical simulation of cavitation flow in axial flow pump and induced pressure fluctuation

作　　者：张德胜[1] 潘大志[1] 施卫东[1] 张光建[1] 

机构地区：[1]江苏大学流体机械工程技术研究中心,江苏镇江212013

出　　处：《华中科技大学学报（自然科学版）》2014年第1期34-38,共5页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51109093);江苏省自然科学基金资助项目(BK2011503);中国博士后科学基金资助项目(2011T500117;2012T50468);江苏省高校优势学科建设工程资助项目

摘　　要：基于改进的空化模型和SSTk-w湍流模型，对轴流泵的流量－扬程曲线、空化特性及其诱导非定常空化压力脉动进行了数值模拟和分析．数值模拟结果表明：设计工况下的扬程、效率和必需空化余量预测误差分别为3．41％，4．10％和6．32％，获得了较高的预测精度；轴流泵叶轮空泡主要分布在叶片背面进口10％～30％区域，从轮缘到轮毂叶片空化区域逐渐减小；轴流泵叶轮出口在空化条件下的压力脉动的主频仍为叶频，谐频为叶频的倍数．叶轮出口受到叶轮外缘严重空化流的影响，在临界空化余量工况下，靠近轮缘处的空化压力脉动幅值是轮毂侧4倍左右；在导叶出口处两者差异逐渐减小，轮缘处的幅值比轮毂处仅大40％左右．随着空化余量不断降低，叶轮内空化趋于严重时，空泡发生区的压力脉动幅值显著增大；但在叶轮进口处，由于空化流向叶轮下游发展，叶轮上游流场受到空化的影响较小，在不同空化余量下压力脉动幅值变化较小．Performance curves and unsteady cavitation pressure fluctuation in the axial flow pump were simulated and analyzed based on modified SST k-w turbulence model and cavitation model. Numerical results show that predictive error values of head, efficiency and hr （net positive suction head required） in design condition are 3.41 %, 4.10% and 6. 32% respectively, compared to the experimental results. Cavitation bubbles are distributed in 10%-30% areas of chord in suction side, which increases from hub to tip gradually. The dominant frequency of pressure fluctuation at impeller outlet in cavitation condition is the blade passing frequency （BPF）, and the harmonic frequency is the times of BPF. The amplitude of the fluctuation near tip, which is affected by the serious cavitation bubbles, is about 4 times of that near hub in hr condition. However, the difference between them reduces gradu- ally in the guide vane outlet. The amplitude of pressure fluctuation near tip is only about 40% of that near hub. The cavitation tends to be serious as h （net positive suction head） decreases, and the amplitude of pressure fluctuation increases significantly. The amplitudes at impeller inlet in different cavita- tion conditions vary little because of the less cavitation effect on the impeller upstream flow field.

关 键 词：轴流泵 空化 必需空化余量 压力脉动 数值模拟 

分 类 号：TH312[机械工程—机械制造及自动化]