双蜗壳离心泵空化流动对隔舌处压力脉动特性的影响  

Effects of cavitating flow on induced pressure fluctuationnear tongue in double-volute centrifugal pump

作　　者：杨敬江[1] 李先军 潘中永[1] 何松 YANG Jingjiang;LI Xianjun;PAN Zhongyong;HE Song(National Research Center of Pumps,Jiangsu University,Zhenjiang,Jiangsu 212013,China)

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

出　　处：《排灌机械工程学报》2020年第5期445-450,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51879120);江苏高校优势学科建设项目。

摘　　要：应用数值计算方法分析了双蜗壳离心泵内空化流动影响隔舌部位压力脉动特性情况,以进一步明晰空化流动诱导泵振动噪声机理.采用SST k-ω湍流模型和Zwart-Gerber-Belamri空化模型,对设计工况下的泵内空化流动和无空化流动进行了非定常数值模拟,数值模拟结果表明:SST k-ω湍流模型能准确预测双蜗壳离心泵的能量特性指标;泵内空化的空泡初始产生于叶轮叶片进口吸力面根部,随着装置空化余量的降低,空泡云沿着叶轮叶片吸力面向叶片出口和前盖板方向发展,叶轮内部空泡的发展并不均匀,加剧了叶轮内部流动的不稳定性.对比叶轮旋转1周在空化和无空化流动状态下发现,2个隔舌处各个监测点的压力脉动具有明显周期性,在无空化状态下,隔板进口处监测点的压力脉动主频为2倍叶频,其他监测点压力脉动主频均为叶频;空化状态下2个隔舌处各个监测点的压力脉动主频均为叶频,压力脉动幅值明显增大.Numerical simulation was applied to analyze effects of cavitating flow on pressure fluctution near the tongue in a double-volute centrifugal pump to investigate the mechansems for pump vibration and noise induced by the flow.The SST k-ωturbulence model and Zwart-Gerber-Belamri cavitation model were selected to carry out unsteady simulations of non-cavitating flow and cavitating flow in the pump under design condition.The numerical results show that the SST k-ωturbulence model can ac-curately predict the pump perfromance.Vapour bubbles occur initlally on the blade suction side near the blade leading edge and impeller hub.With the decrease of NPSHA(net positive suction head available),the vapour bubbles develop along the blade suction side towards the blade outlet and impeller shroud.The vapour bubbles uneven development in different flow passages intensifies the unstablility of the flow in the impeller.Comparing the flow patterns of cavitation and non-cavitation flows in one revolution of the impeller,the pressure fluctuation of two monitoring points near tongue domonstrates an obvious periodicity.The dominant frequency of the pressure fluctuation near the inlet of the deflector is double the blade passing frequency(BPF)under non-cavitation condition.The dominant frequency of the pressure flucutation at the other monitoring points is BPF under both cavitation and non-cavitation conditions.The amplitude of the pressure fluctuation near all the monitoring points increases significantly under cavitation condition.

关 键 词：离心泵 双蜗壳 空化 隔舌 压力脉动 

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