水气最大密度比对轴流泵空化计算的影响  

Effect of the Maximum Density Ratio between Liquid and Vapor on Cavitating Simulation of Axial-flow Pump

作　　者：施卫东[1] 张光建[1] 张德胜[1] 徐焰栋[1] 

机构地区：[1]江苏大学流体机械工程技术研究中心,镇江212013

出　　处：《农业机械学报》2014年第5期65-70,共6页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金资助项目(51109093);'十二五'国家科技支撑计划资助项目(2011BAF14B01);江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：利用商业软件CFX的二次开发技术,将滤波器湍流模型(FBM)耦合进软件,并结合均相流空化模型对轴流泵在不同工况下的空化流场进行数值计算,分析了空化模型中的水气最大密度比对轴流泵空化特性计算的影响,并与实验结果进行对比。结果表明:基于RNG k-ε的FBM湍流模型能够较准确地预测轴流泵的外特性;在3种工况下(320、392、480 m3/h),采用真实水气密度比43 197得到的临界汽蚀余量与默认值1 000相比更接近实验值,相对误差分别为1.93%、4.73%和8.09%;随着最大密度比的提高,计算出的空泡面积、空泡含气率和叶顶泄漏涡作用范围也随之增大,这是导致预测的临界汽蚀余量产生差异的原因。The filter based model （FBM）, which was introduced into CFX by user defined subroutine, and a homogeneous cavitation model was used to calculate cavitating flow of the axial-flow pump at different conditions. The effect of a maximum density ratio between liquid and vapor in the cavitation model on cavitation characteristic simulation was investigated. The results compared with experimental data show that the FBM based on RNG k-εmodel can predict the external characteristic of axial flow pump well. The critical NPSHs predicted by the true density ratio 43197 at three different conditions （Q=320, 392, 480m^3/h） are closer to experimental values than the default 1000 and the relative errors are 1.93%, 4.73% and 8.09% respectively. With the increasing of maximum density ratio, the calculated vapor area, vapor volume fraction and the range of tip leakage vortex increase as well. This may be the cause of different predicted critical NPSHs.

关 键 词：轴流泵 空化 最大密度比 滤波器模型 

分 类 号：TH311[机械工程—机械制造及自动化]