轴流泵偏工况压力脉动和内流特性分析  

Analysis of pressure fluctuation and internal flow characteristics of axial flow pumps under off design conditions

作　　者：王开杰 赵勇[1] 王生辉 肖业祥[2] 汪程鹏 张瑾[2] WANG Kaijie;ZHAO Yong;WANG Shenghui;XIAO Yexiang;WANG Chengpeng;ZHANG Jin(Key Laboratory of Highway Construction Technology and Equipment of Ministry of Education,Chang’an University,Xi’an 710064,China;State Key Laboratory of Hydroscience and Engineering&Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China;The Institute of Seawater Desalination&Multipurpose Utilization,MNR,Tianjin 300192,China;Mechanical and Electrical Engineering College,Hainan University,Haikou 570228,China)

机构地区：[1]长安大学道路施工技术与装备教育部重点实验室,西安710064 [2]清华大学水沙科学与水利水电工程国家重点实验室&能源与动力工程系,北京100084 [3]自然资源部天津海水淡化与综合利用研究所,天津300192 [4]海南大学机电工程学院,海口570228

出　　处：《水力发电学报》2023年第5期86-96,共11页Journal of Hydroelectric Engineering

基　　金：海南省省重点研发计划(ZDYF2021SHFZ057);水沙国家重点实验室开放研究基金资助项目(sklhse-2022-KY-06)。

摘　　要：轴流泵在偏离设计工况特别是小流量工况马鞍区附近运行时,流道内部强烈涡旋会造成剧烈的压力脉动,影响了泵组的安全稳定运行。本文以高比转速轴流泵为研究对象,对轴流泵5个流量工况点进行了整体流道三维流动计算,探讨该轴流泵运行时的非定常流动特性。数值计算采用RNG k-ε湍流模型,5个定常工况点计算的外特性曲线与轴流泵性能特点研究结果一致。对0.2Q_(d)和1.0Q_(d)工况进行非定常计算,结果显示,相同位置测点间的压力脉动混频幅值和频率均存在明显差异,0.2Q_(d)工况下相同位置测点间的压力脉动峰峰值最大超过1.0Q_(d)工况下4倍,说明此时流道内的流态分布很不均匀。测点离叶轮和导叶越近,低频脉动的主频受动静干涉引起的3fn和5fn脉动幅值就会明显增强,0.2Q_(d)工况下流道内测点受动静干涉作用的影响更强,脉动幅值为1.0Q_(d)工况下相同位置测点的3~5倍,且在转轮和导叶流道内影响的范围更广。结果表明,0.2Q_(d)小流量工况运行时压力脉动比1.0Q_(d)设计工况明显剧烈,叶轮和导叶内受动静干涉作用的影响更强,导叶流道内充满了严重的流动分离和漩涡。When a running axial flow pump deviates from its design condition,especially at very low flows,strong vortices in its flow channel will cause severe pressure pulsation,deteriorating the safe and stable operation of the pump unit.In this paper,by examining a high specific speed axial flow pump as a case study,we simulate numerically three-dimensional flows in its whole flow channel for five operating points by using a code equipped with a RNG k-εturbulence model,and discuss its unsteady flow characteristics.Its external characteristic curves at five steady operating points are verified,and we find they agree well with the design performances.We calculate the unsteady cases at two flows of 0.2Q_(d)and 1.0 Q_(d).The results show obvious differences occur between the two conditions in the amplitude and frequency of pressure pulsation mixing at the same measuring points.At the flow of 0.2Q_(d),the maximum peak-to-peak value of pressure pulsation is four times higher than that at 1.0 Q_(d),indicating highly uneven flow patterns in the channel.In unsteady cases,the dynamic and static interference,usually causing low-frequency pulsation,will greatly enhance the 3fn and 5fn pulsation amplitudes of its principal frequencies.At the measuring points closer to the impeller and guide vanes,these increases are more significant,and the flows are more sensitive to the interference,with the pulsation amplitudes of 3-5 times that of 1.0 Q_(d);the influence in the runner and guide vane section is stronger.Thus,pressure fluctuation at the lower flow is more severe,and the impeller and guide vane sections are more affected by the static and dynamic interference,so that severe flow separation and more vortices occur in the guide vane channels.

关 键 词：轴流泵 小流量工况 压力脉动 内流特性 数值计算 

分 类 号：TV734[水利工程—水利水电工程] TK730[交通运输工程—轮机工程]