低水头下水泵水轮机水轮机工况压力脉动研究  

Pressure fluctuations of pump turbine in turbine mode under low head

作　　者：李仁年[1] 谭海燕[1] 李琪飞[1] 韩伟[1] 蒋雷[1] 

机构地区：[1]兰州理工大学,兰州730050

出　　处：《水力发电学报》2015年第8期85-90,共6页Journal of Hydroelectric Engineering

基　　金：国家科技支撑计划子课题(2011BAF03B01-05);甘肃省自然科学基金(1310RJZA023);青年科学基金(51209113)

摘　　要：基于Realizable k-ε湍流模型,对某蓄能电站模型水泵水轮机进行几何建模,设定压力脉动监测点,进行三维全流道水轮机工况非定常数值计算,分析导叶开度为29mm,33mm,37mm和41mm四个工况下各监测点的压力变化,并与模型试验结果进行对比,研究水泵水轮机在低水头下的压力脉动特性。结果表明：Realizable k-ε湍流模型对低水头下水泵水轮机压力脉动的数值模拟可行,在大开度工况时更加精确;导叶开度为29mm时水泵水轮机内部监测点压力脉动最强,随着导叶开度的增加压力脉动在逐渐的减弱;转轮旋转形成的＂活动导叶-转轮-尾水管＂两级动静干涉,使活动导叶与转轮之间无叶区内监测点的压力脉动时域图呈现周期性变化规律,对应主频为叶频,尾水管锥管段时域图也呈现周期性变化,并在其频域图叶频处出现一个峰值;肘管内监测点压力脉动由于尾水涡带的影响主频为0.17~0.56倍转频的低频分量。A numerical model of a low-head pump turbine has been developed to study its characteristics of pressure fluctuations using a realizable k-ε turbulence model, focusing on full-passage simulations of the unsteady flows for four guide vane opening conditions, i.e., a0=29mm, 33mm, 37mm, and 41mm. Pressure signals at four sampling points were compared with experimental measurements. The results show that this turbulence model has a good overall performance and its accuracy is better in the cases of larger openings. Generally, pressure fluctuations tend to be weaker at larger openings, and pressure signals at the opening of 29mm show the strongest fluctuations of the four openings. Because the rotating wheel causes a rotor-stator interaction in the flow passage from the guide vanes through the runner to the draft tube, pressure fluctuations are periodic at the sampling points in the two vaneless spaces： the section between the guide vanes and runner, and the cone section of draft tube. The dominant frequencies of these time variations are equal to the frequency of blade passing through, and at the sampling points in the cone section a peak value appears on the amplitude-frequency curves. Due to the vortex strip in draft tube, the dominant frequencies at the sampling points in bent pipe are 0.17-0.56 times of the frequency of runner passing through.

关 键 词：水泵水轮机 低水头 压力脉动 数值模拟 

分 类 号：TK734[交通运输工程—轮机工程]