中文摘要：

选用Standard kε和RNG kε湍流模型分别在0.62Qd、0.8Qd、1.0Qd、1.1Qd和1.2Qd工况下对两级双吸离心泵内部流场进行了定常和非定常模拟,分析了泵的能量特性和压力脉动特性。研究发现,吸水室内压力脉动主频约为2倍转频,各监测点的压力脉动幅值分布呈现一定规律但相差不超过1%;叶片区各监测点压力脉动主频为2倍的转频,从进口边到出口边压力脉动幅值呈现出逐渐增大的趋势;压水室内各监测点压力脉动主频为叶片通过频率,远离隔舌方向,压力脉动幅值先增大后减小,幅值最大点出现在第二蜗道远离隔舌一定角度的位置。泵内压力脉动幅值随着偏离设计工况而增大,其中叶片通过频率下的压力脉动随着流量增加而逐渐增大,1.2Qd工况1倍叶片通过频率下的压力脉动幅值是设计工况下的125%;转频下的压力脉动随着流量减小而增大,隔舌处监测点0.62Qd工况1倍转频下的压力脉动幅值是设计工况的142%。在同一工况下,一级和二级对应部件的压力脉动时域及频域特性相似。

英文摘要：

To investigate the energy characteristics and pressure fluctuations of a two-stage double-suction centrifugal pump,the standard kε and RNG kε turbulent flow models were chosen for the steady and unsteady flow simulations at 0.62,0.8,1.0,1.1 and 1.2 designed flow rate conditions.The results showed that the second multiple frequency of the impeller rotation dominated the pressure fluctuations in the suctions.The fluctuation amplitudes for all the monitored points in suctions were very similar and the difference was less than 1%.The second multiple frequency of the impeller rotation also dominated the pressure fluctuations on the impeller blade surfaces where the amplitude became larger than that at suctions.The blade passing frequency dominated the pressure fluctuations in the volute and the largest amplitude was at the point some distance away from the volute tongue.The amplitude of pressure fluctuation increased when the pump operation condition was deviated from the design point.In the volute tongue region,the pressure fluctuation amplitude of blade passing frequency at 1.2 designed flow rate is 1.25 times of the one at designed flow rate,while the ratio at 0.62 designed flow rate is 1.42.