基于LDV的离心泵小流量工况内流场测量  

Measurements of internal flow in centrifugal pump at part-load conditions based on LDV

作　　者：冯建军[1] 武桦[1] 罗兴锜[1] 卢金玲[1] 

机构地区：[1]西安理工大学水利水电学院,陕西西安710048

出　　处：《排灌机械工程学报》2013年第2期109-112,122,共5页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(50909081);陕西省百人计划项目(2012)

摘　　要：为了研究离心泵中的脱流现象,利用二维激光多普勒测速仪对一低比转数带导叶扩压器离心泵叶轮在4种小流量工况下(0.75Qd,0.50Qd,0.40Qd和0.30Qd)的内部流动进行了精确测量.基于测量结果,得到了各种工况下测量点上的相平均速度场和湍流强度场.通过分析测量结果发现在工况0.75Qd下,叶轮内没有脱流发生.而在工况0.50Qd,0.40Qd和0.30Qd下,叶轮流道中呈现"两流道"脱流现象:相邻两个叶轮流道中的脱流大小和类型完全不同,但此时脱流呈现出120°的周期性,这可能与叶轮叶片数和扩压器导叶叶片数的比率(6∶9)有关.此外,对比分析了各种工况下各个速度分量和湍流强度的分布规律.结果显示:离心泵叶轮内的湍流强度随着流量的减小而增大.在离心泵叶轮出口附近,流量为0.75Qd时,最大湍流强度达到0.06(基于叶轮出口圆周速度u2);而对于工况0.50Qd,0.40Qd和0.30Qd,其最大湍流强度达到了0.12～0.14.In order to investigate flow separations at part-load conditions in centrifugal pumps, two-di- mensional laser doppler velocimetry was successfully applied to a low specific speed radial diffuser pump to precisely measure unsteady flow fields at four part-load conditions （0.75Qd, 0. 50Qd, 0.40Qd and 0.30Qd） in the impeller. Based on measurements, the phase-averaged velocity field and turbu- lence intensity field were obtained for each measuring point. The analysis of the measurements shows that there is no flow separation at 0.75Qd. However, a two-channel flow separation was observed in the impeller at O. 50Qd, 0.40Qa and 0.30Qd ： the amounts of flow separation were quite different between two adjacent flow channels. However, the flow separations exhibit a periodicity of 120°, possibly due to the blade number ratio between impeller blades and diffuser vanes （6： 9）. Furthermore, the velocity components and turbulence intensity were analyzed and compared among all four operating points. The results show that turbulence intensity increases as flow rate decreases. The highest turbulence intensity near the impeller outlet is 0.06 （based on u2） at 0.75Qd, and the highest one reaches about 0.12 - 0.14 at operating points 0.50Qd, 0.40Qd and 0.30Qd.

关 键 词：离心泵 小流量工况 测量 激光多普勒测速仪 湍流 “两流道”脱流 

分 类 号：S277.9[农业科学—农业水土工程] TH311[农业科学—农业工程]