叶顶间隙对轴流泵轮缘压力脉动影响的数值预测  

Numerical Investigation of Pressure Fluctuations on Axial-flow Pump Blades Affected by Tip-gap Size

作　　者：黎耀军[1] 沈金峰[1] 洪益平[1] 刘竹青[1] 

机构地区：[1]中国农业大学水利与土木工程学院,北京100083

出　　处：《农业机械学报》2014年第5期59-64,58,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金资助项目(51009138)

摘　　要：为分析不同叶顶间隙下轴流泵轮缘区非定常流动特征,采用大涡模拟方法和滑移网格技术,对5种轮缘间隙下轴流泵设计工况的非定常湍流进行了数值计算,分析了间隙尺寸对泵外特性、轮缘泄漏涡形态及叶片近轮缘区压力脉动特性的影响。结果显示:叶顶间隙从0.001D2增加到0.003D2,泵扬程和效率分别下降6.2%和5.6%;间隙值大于0.001D2时,轮缘间隙主泄漏涡发展至相邻叶片正面,间隙区产生大量次泄漏涡;受泄漏涡影响,叶片正面中部近轮缘侧压力脉动幅值随轮缘间隙增加而增大;不同间隙尺寸下,叶片背面近轮缘处压力脉动主频均为叶轮转频fr,叶片正面对应点的压力脉动主频则随间隙变化存在明显差异。The effects of tip gap size on the unsteady flow characteristics in an axial flow pump at design flow rate were investigated using large eddy simulation with sliding mesh technique. Five configurations with different tip gap sizes were considered, and the tip leakage vortexes and pressure pulsations of near tip zone on the blades were studied in detail. The results indicate that as the tip clearance increased from 0.001D2 to 0.003D2, the head and efficiency of the pump reduce by 6.2% and 5.6%, respectively. When the tip gap is larger than 0.001D2, the dominant tip-leakage vortex extend to the pressure side of adjacent blade and the secondary tip leakage vortexes formed in the tip-gap region. Affected by the tip leakage vortex, the amplitude of the pressure pulsation of the monitoring point PP6 （on the pressure side and near the middle of the blade tip edge） increases with the tip gap size. For different tip clearance configurations, the rotating frequency （fr） dominates the pressure pulsations of near tip zone on suction side of the blades, while the dominant frequency of near tip region on the pressure side changes with the tip-gap size.

关 键 词：轴流泵 叶顶间隙 轮缘泄漏涡 压力脉动 大涡模拟 

分 类 号：TH312[机械工程—机械制造及自动化] O351.2[理学—流体力学]