基于改进Kunz模型的船用离心泵空化特性  

Analysis of cavitation characteristics of marine centrifugal pump based on modified Kunz model

作　　者：王勇[1] 陈杰[1] 罗凯凯 刘东喜[2] 李雨[1] 严骏[1] 

机构地区：[1]江苏大学国家水泵及系统工程技术研究中心,江苏镇江212013 [2]上海交通大学海洋工程学院,上海200240

出　　处：《排灌机械工程学报》2017年第5期381-386,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：江苏省"六大人才"高峰项目(GDZB-017);流体及动力机械教育部重点实验室开放课题资助项目;江苏省产学研联合创新资金--前瞻性联合研究项目(BY2015064-10);江苏高校优势学科建设工程项目

摘　　要：为研究空化对船用离心泵的影响,把湍流压力脉动的影响引入到Kunz模型以修正汽化压力.以一台比转数为132.7的船用离心泵为研究对象,在不同流量工况情况下,进行了空化性能的模拟计算和试验研究.通过对比空化性能的数值计算结果和试验值发现,在不同流量系数下Kunz模型改进前后都能捕捉到扬程系数下降时的临界空化数,但改进后的Kunz模型预测到的临界空化数更加贴近试验值.此外,分析了设计工况下基于改进Kunz模型获得的叶片间气相体积分布和叶片表面载荷分布,研究表明:空泡首先在叶片进口边的吸力面产生,随着空化数的减小,叶片压力面也会有少量空泡产生,少数位置吸力面和压力面相接,最后空泡充满整个流道,导致泵的性能下降;随着空化数的减小,叶片进口边附近会先产生低压区,随后沿着叶片向出口边叶片蔓延,最后在叶片吸力面和压力面都存在大面积的低压区;叶片5(隔舌附近)比叶片2(叶片5相对的叶片)中间流线承受的载荷要小,随着空化数的减小,叶片表面压力有所减小,且叶片2进口处压力出现了零点,这主要是空化程度加剧导致的.Cavitation erosion may be inevitable when a marine centrifugal pump is in operation. Thus, in order to investigate effects of cavitation on the performance of a marine centrifugal pump, the turbu- lent pressure fluctuation was involved in the Kunz cavitation model to alter the phase transition critical pressure, i.e. vaporization pressure. A marine centrifugal pump with a specific speed of 132.7 was chosen as a study model and its cavitation performance was predicted numerically and experimentally at different flow rates. It was found that both Kunz model and its updated version were able to capture the critical cavitation condition, and the head curve due to the updated model was in better agreement with the observed curve. In addition, the vapor volume fraction distribution between two blades and the blade loading distribution based on that improved model were analyzed at the design point. The results show that bubbles were generated on the pressure suction side near the leading edge at first, then a small amount of bubbles occurred on the blade pressure side with decreasing cavitation number. At last, the impeller passages were fully blocked by bubbles, leading to a declined performance for the centrifugal pump. With the decrease of cavitation number, a low pressure zone occurred near the blade inlet edge firstly, then spread along the bl.ade toward the blade outlet, eventually the low pressure co- vered the blade pressure and suction sides. The blade loading in the middle streamline of blade 5 （ the blade near the tongue） was smaller than that in blade 2 （ the blade is axisymmetric with blade 5 ）. With the decrease of cavitation number, the pressure on the blade surfaces was reduced, and there was a ze- ro pressure at the inlet of blade 2, this is mainly caused by cavitation aggravation.

关 键 词：船用离心泵 空化特性 Kunz模型 试验 数值分析 

分 类 号：S277.9[农业科学—农业水土工程] TH311[农业科学—农业工程]