基于FBM模型的轴流泵空化流动特性CFD分析  

CFD analysis of cavitation flow for axial-flow pumpbased on FBM model

作　　者：吕蕊蕊 郑源[1] 张德虎[1] 于安 LYU Ruirui;ZHENG Yuan;ZHANG Dehu;YU An(College of Energy and Electrical Engineering Hohai Universit y,Nanjing 211100,China)

机构地区：[1]河海大学能源与电气学院,南京211100

出　　处：《南水北调与水利科技（中英文）》2020年第1期150-165,共16页South-to-North Water Transfers and Water Science & Technology

摘　　要：轴流泵运行工况多变,容易发生空化,会严重影响泵的水力性能。为研究轴流泵空化工况下的流动特性,进行了全流道空化流动数值模拟和压力脉动分析,通过比较实验数据和不同湍流模型的计算结果,验证了FBM模型在预测轴流泵外特性和空化性能方面的优越性。研究结果表明:FBM模型预测非设计条件下的数值误差最小,特别是在具有小流量条件的流场中误差最小,其中平均扬程误差1.19%,平均效率误差5.31%;FBM在预测空泡体积数、含气量上的精度均大于其他三种湍流模型,与实验结果最接近;在NPSH=5.25m空化刚开始阶段,叶片上的压力脉动的主要频率位于fn及其倍频处,叶片吸力面的压力监测点由于受到空泡溃灭影响出现大量低频幅值,导叶出口监测点的压力脉动受到导叶片背面流动状态的影响出现大量低频信息。The working condition of the axial flow pump is changeable,and cavitation is easy to occur,which can seriously affect the hydraulic performance of a pump.To study the flow characteristics of the axial flow pump under cavitation condition,numerical simulations and pressure pulsation analysis of cavitation flow in full channel were carried out.The superiority of FBM model in predicting the external characteristics and cavitation performance of axial flow pump was verified by comparing the experimental data based on calculated results of different turbulence models.The results showed that the FBM model had least error in predicting external characteristics under non-design conditions,especially in the flow field under small flow conditions.The average lift error was 1.19%,and the average efficiency error was 5.31%,respectively.The accuracy of FBM in predicting cavitation volume and gas fractionwas higher than other three turbulence models,which was mostly close to the obtained experimental results.In the initial stage of NPSH=5.25 mcavitation,the main frequency of pressure pulsation on the blade was located at fn,and its frequency was doubled,while large number of low-frequency amplitudes appeared at the pressure monitoring point on the suction surface of the blade due to the influence of cavitation collapse.The pressure pulsation at the outlet of the guide vane was influenced by the flow pattern on the back of the guide blade.

关 键 词：湍流模型 误差 外特性 空化性能 压力脉动 

分 类 号：TVL36.2[水利工程]