摘要
离心泵内的不稳定流动现象会产生压力脉动,为了改善半开叶轮小流量工况下的内部流场和压力脉动,通过在前盖板上布置周向槽,分析了周向槽对叶轮内部流动特性和压力脉动的影响。结果表明,周向槽为泄漏流提供了周向通道,泄漏流能够从槽内快速通过,降低了泄漏流的驱动力,使得主流与泄漏流的交界面向叶片尾缘移动;靠近叶顶间隙叶片进口相对液流角和低速区面积减小,轴向速度增大,泄漏流导致的不稳定流场和阻塞现象减弱,近失稳工况点对应的流量向小流量工况偏移;周向槽不仅改善了前缘溢流,使得叶轮内低频压力脉动幅值下降,而且消除了叶片前缘泄漏流形成的回流及其诱发的2.2 f_(n)特征频率。研究发现周向槽能够通过有效抑制不稳定流动及其诱发的压力脉动来改善离心泵小流量工况的运行稳定性。
Unstable flow inside a centrifugal pump can cause pressure fluctuation.Here,to improve internal flow field and pressure pulsation of a half open impeller under the condition of small flow rate,effects of circumferential groove on internal flow characteristics and pressure pulsation of the impeller were analyzed by arranging circumferential groove on the front cover plate of the pump.The results showed that circumferential groove provides a circumferential channel for leakage flow,and leakage flow can quickly pass through groove to reduce driving force of leakage flow and make the interface of main flow and leakage flow move towards trailing edge of blade;the relative flow angle and the area of low-speed zone near blade tip clearance and blade inlet decrease,axial flow velocity increases,unsteady flow field and blockage phenomenon caused by leakage flow weaken,and the flow rate corresponding to near unstable condition point shifts to that under small flow rate condition;circumferential groove not only improves leading edge overflow and reduces amplitude of low-frequency pressure fluctuation in impeller,but also eliminates backflow caused by leading edge leakage flow and the 2.2 f_(n) characteristic frequency induced by backflow;circumferential groove can effectively suppress unsteady flow and pressure pulsation induced by it to improve the operation stability of centrifugal pump under the condition of small flow rate.
作者
王李科
卢金玲
廖伟丽
王维
郭鹏程
罗兴锜
WANG Like;LU Jinling;LIAO Weili;WANG Wei;GUO Pengcheng;LUO Xingqi(State Key Lab of Eco-hydraulics in Northwest Arid Region,Xi’an University of Technology,Xi’an 710048,China;College of Water Resource and Hydro-electric Engineering,Xi’an University of Technology,Xi’an 710048,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2021年第17期175-182,228,共9页
Journal of Vibration and Shock
基金
国家自然科学基金(51879216,51679196,51839010)。
关键词
离心泵
泄漏流
周向槽
压力脉动
前缘溢流
centrifugal pump
leakage flow
circumferential groove
pressure fluctuation
leading edge overflow
