叶顶间隙对低比转速混流泵性能及内部流场影响的数值研究  

Study of Tip Clearance Effects on Performances and Flow Field of a Low Specific Speed Mixed-flow Pump

作　　者：张文武 余志毅[1] 祝宝山[2] 杨策[1] 

机构地区：[1]北京理工大学机械与车辆学院,北京100081 [2]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《机械工程学报》2017年第22期182-189,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(51579006;51679122)

摘　　要：为了解叶顶间隙对低比转速混流泵性能及内部流场的影响,选取无叶顶间隙和叶顶间隙δ分别为0.25 mm、0.75 mm和1 mm共四种方案,基于ANSYS-CFX对一比转速为149的混流泵进行了全流道数值模拟。计算域采用ICEM-CFD和Turbo Grid进行结构化网格划分。利用Tecplot对计算结果进行处理,得到叶顶间隙对外特性参数、轮缘泄漏、流道中心S2流面流场等的影响。结果显示,叶顶间隙对大流量工况(1.25Qd和1.5Qd)下性能参数的影响大于小流量工况(0.5Qd和0.75Qd),且效率减小量与叶顶间隙变化量的比值(Δη/Δδ)和相对流量m之间近似呈二次抛物线关系;当间隙为0.75 mm时,随着流量的增加,在叶轮流道进口附近形成的旋涡逐渐向出口方向移动,且旋涡强度及其对主流的影响范围均增大;当间隙进一步增大到1 mm时,泄漏流和主流之间发生了更为严重的卷吸效应。To explore the tip clearance effects on performance and flow field of the low specific speed mixed-flow pump, tip clearanceδ of 0.25 mm, 0.75 mm and 1 mm, along with no tip clearance, are selected. The steady flow was simulated with ANSYS-CFX for the whole flow passage of a mixed-flow pump with a specific speed of 149. The structured mesh of the computation domain is generated with ICEM-CFD and Turbo Grid, post-processing is done with Tecplot software. The results show that the effects of tip clearance on performance parameters in large flow rate conditions（1.25 Qd, 1.5 Qd） are greater than that in small flow rate conditions（0.5 Qd,0.75 Qd）, and an approximate parabolic relationship is obtained between the ratio of efficiency reduction to tip clearance variation（Δη/Δδ） and the relative discharge m; When the tip clearance value is 0.75 mm, as the discharge increases, the vortex forms near the impeller passage inlet and gradually moves toward the impeller outlet. Meanwhile, the vortex intensity and its influence range on the mainstream are increased. More serious entrainment effect is happened between the leakage flow and the mainstream when the tip clearance increases to 1 mm.

关 键 词：低比转速 混流泵 叶顶间隙 泄漏涡 卷吸效应 

分 类 号：TH313[机械工程—机械制造及自动化]