球形泵变转速下空化特性及性能分析

Cavitation characteristics and performance analysis of spherical pump under variable speed

球形泵是机电产品中的一种新型结构泵,空化现象仍然是影响水泵性能的重要因素。针对球形泵在工作时因转速所导致的空化问题,对变转速下的球形泵的空化特性及性能进行了研究。首先,采用计算流体动力学方法,并运用动网格技术,模拟了球形水泵的内部流场;然后,根据模拟仿真结果分析了转速对工作腔内空化过程的影响,获得了水泵容积效率的变化规律;最后,根据模拟结果对球形泵吸液口进行了改进。研究结果表明:球形泵工作时产生的空化现象主要发生在吸液阶段;在吸液初期与末期,较小的吸液口面积会造成工作腔内的液体压力迅速下降,吸液孔口附近和工作腔中部区域发生较明显空化;高转速时,较大的工作腔容积变化率导致空化加剧,容积效率先增大后减小;当转速为500 r/min~3000 r/min时,吸液末期腔内空化体积分数为1.01%~8.08%,球形泵容积效率为91.16%~85.51%;改善吸液口可以增大进液通道的有效工作面积,容积效率由85.51%提高至90.15%。该研究可为新型球形泵的优化设计提供参考。

The spherical pump is a new type of structural pump in electromechanical products,and the cavitation phenomenon is still an important factor affecting the performance of the pump.A study was conducted on the cavitation characteristics and performance of a spherical pump under variable rotational speed to address the cavitation problem caused by rotational speed during operation.Firstly,the computational fluid dynamics(CFD)method and dynamic grid technology were used to simulate the internal flow field of a spherical water pump.Then,based on the simulation results,the influence of rotational speed on the cavitation process in the working chamber was analyzed,and the variation law of volumetric efficiency was obtained.Finally,based on the simulation results,the suction port was improved.The research results indicate that the spatio temporal phenomenon of spherical pumps mainly occurs during the suction stage.The small suction port area in the early and late stages of suction causes a rapid decrease in liquid pressure in the working chamber,and significant cavitation occurs near the suction port and in the central area of the working chamber.At high rotational speeds,the larger change rate of the working chamber volume leads to increased cavitation,and the volumetric efficiency first increases and then decreases.When the rotational speed is between 500 r/min and 3000 r/min,the volume fraction of cavitation in the cavity at the end of the suction stage is 1.01%~8.08%,and the volumetric efficiency of the spherical pump is 91.16%~85.51%.After improving the suction port,inlet channel effective working area increased,and the volumetric efficiency increased from 85.51%to 90.15%.The research can provide reference for the optimization design of new spherical pumps.