离心泵蜗壳内非定常流动特性的数值模拟及分析  

Numerical Simulation and Analysis of Unsteady Flow Characteristics in Centrifugal Pump Volute

作　　者：孟根其其格 谭磊[1] 曹树良[1] 王玉川[3] 

机构地区：[1]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 [2]内蒙古化工职业学院测控与机电工程系,呼和浩特010070 [3]西北农林科技大学水利与建筑工程学院,杨凌712100

出　　处：《机械工程学报》2015年第22期183-190,共8页Journal of Mechanical Engineering

基　　金：清华大学自主科研计划(2014z21041;20141081231);西华大学流体及动力机械教育部重点实验室(szjj2015-021);国家自然科学基金(51176088)资助项目

摘　　要：基于RNG k-ε湍流模型和Zwart-Gerber-Belamri空化模型,对离心泵内部非空化和空化工况下的非定常流动特性进行数值模拟,分析空化模型中凝结项经验系数对数值模拟结果的影响,并根据试验结果修正离心泵空化流动数值模拟中凝结项经验系数;数值模拟得到的离心泵扬程随有效空化余量的变化曲线与试验结果吻合较好,验证数值计算模型和方法的准确性和可靠性。数值模拟结果表明:离心泵非定常流动中,非空化、临界空化和充分发展空化工况下,蜗壳内监测点的压力脉动主频均为叶片通过频率;空化对离心泵蜗壳内压力脉动的影响较大,非空化时压力脉动最大幅值在蜗舌处,空化时压力脉动最大幅值在第1断面附近,其原因是离心泵出现空化时第1断面处旋涡强度增强,且随时间变化剧烈,对流动产生强烈扰动。The unsteady flow in a centrifugal pump is numerically simulated by using the RNG k-e turbulence model and the Zwart-Gerber-Belamri cavitation model. The influence of condensation coefficient of the cavitation model on numerical simulation is analyzed. According to the experimental result, the value of condensation coefficient is modified. The calculated variation of pump head with the available net positive suction head is in good agreement with the experimental data, so the accuracy and reliability of the numerical modal and method are verified. The results demonstrate that the dominant frequencies of pressure fluctuation in the volute at operating conditions of non-cavitation and cavitation are both the blade pass frequency. The cavitation has great influence on pressure fluctuation in volute. The maximum amplitudes of pressure fluctuation appear at the tongue of the volute and the first section of the volute for non-cavitation and cavitation conditions, respectively. It is caused by the strength of vortex enhances at cavitation condition and changing with time, which disturbs the flow in the first section.

关 键 词：离心泵 凝结项经验系数 蜗壳 非定常流动 数值模拟 

分 类 号：TH311[机械工程—机械制造及自动化]