半开式离心泵变工况叶顶间隙的流动特性  

Flow characteristics of blade tip clearance in semi-open centrifugal pump in variable condition

作　　者：贾晓奇[1] 聂小林 涂必成 崔宝玲[3] 

机构地区：[1]浙江大学动力机械及车辆工程研究所,杭州310027 [2]嘉利特荏原泵业有限公司,温州325204 [3]浙江理工大学浙江省流体传输技术研究重点实验室,杭州310018

出　　处：《农业工程学报》2015年第4期91-96,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(51275461);国家自然科学基金资助项目(51276172);浙江省科技计划项目(2013C01141)

摘　　要：为研究不同工况下,叶顶间隙对半开式叶轮离心泵内部流场及外特性的影响,该文对某半开式叶轮离心泵内部三维湍流流场进行数值模拟。揭示了离心泵内不同工况下叶轮流道和叶顶间隙层内的流动规律,对比分析了4种不同流量工况下叶顶间隙泄漏涡的流动特性、叶顶间隙层总压与相对速度分布,以及流量的变化对离心泵外特性的影响。结果表明:在小流量(设计流量为1.5 m3/h)时,间隙层内充满了泄漏涡,随着流量的增加涡核逐渐减少;大流量时涡核几乎消失,但此时流体速度激增,流动冲击损失变大在叶轮出口与间隙层附近存在着大面积回流,小流量时回流几乎占据了整个出口。通过模型泵外特性试验,验证了数值计算的准确性。该文为离心泵叶顶间隙设计及水力优化提供了参考。The centrifugal pumps with semi-open impellers have been widely applied in petrol chemical industry, aerospace industry, power energy, etc. The tip clearance flow is a very complex turbulent flow in which the vortex, secondary flow, and recirculation flow are existent simultaneously, and it plays an important role for internal flow characteristics and external performances. In recent years, lots of numerical and experimental studies have been carried out to investigate the tip clearance flow and improve the performance of the semi-open impeller centrifugal pump. In this paper, numerical simulation and performance test are carried out on the centrifugal pump with a semi-open impeller. Influences of tip clearance on performance and the details of flow in tip clearance layer are studied at four different flow rate conditions. In the numerical simulation, the PRO/E software is used to generate computational geometries. The compatible preprocessor, GAMBIT is used to generate meshes. The commercial CFD software Fluent 6.3 is used to solve the N–S equations. The SIMPLEC algorithm is used to couple pressure and velocity. Second order upwind discretizations have been used for convection terms and the central difference schemes are used for diffusion terms. Three-dimensional viscous incompressible flow field simulations have been performed using multiple reference frame coordinates. The impeller and inducer region is taken as a rotating reference frame with a constant angular speed of 1 450 r/min, and the other surfaces are defined as stationary reference frame. And the boundary conditions are velocity condition at inlet and outflow at outlet of the pump. Also, no-slip wall conditions have been used for the rest surfaces of the pump. Also, the experimental studies are carried out on the tested centrifugal pump with tip clearances of 1.0 mm, and the results are compared with the numerical calculations. Seal gaskets are used to adjust the tip clearance. Tungsten wires（the diameter is 3 mm） are placed in three positions

关 键 词：离心泵 数值模拟 模型 半开式 离心叶轮 变工况 叶顶间隙 

分 类 号：TH311[机械工程—机械制造及自动化]