基于Omega涡识别方法的离心泵内非定常流动数值评价

Numerical Evaluation of Unsteady Flow in a Centrifugal Pump by Omega Vortex Identification Method

离心泵内部非定常流动与流场中生成的旋涡密切相关。本文采用Omega涡识别方法研究离心泵流场涡结构及非定常流动特性,阈值选择为0.51。分析得出LES湍流模型相对比其他两种湍流模型涡识别结果更为细致,对叶片流道中的小涡结构可以很好地捕捉。设计工况下,LES模型识别出的涡面积数值是DDES模型的1.15倍,是SST k-ω模型的1.55倍。压力脉动受流场空间位置与工况影响较大,其主要激励为叶频,并且压力脉动强度与涡面积密切相关。叶轮出口处的涡结构周期性脱落,在隔舌处会撞击隔舌而破裂。离心泵动静干涉的产生与叶轮出口处的涡结构脱落有关。

The internal unsteady flow is related to the Gansu Province,vortices generated in the channels of the centrifugal pump.In the present paper,the Omega vortex identification method was applied to study the vortex structure and unsteady flow characteristics of the centrifugal pump,and the threshold was 0.51.The results showed that the LES model was more detailed than the other two turbulence models,and it can capture the small vortex structure in the blade flow channel.At design conditions,the vortex area identified by LES was 1.15 times that of the DDES model and 1.55 times that of the SST k-ω model.Leaf frequency mainly excites pressure pulsation.The vortex area was closely related to the unsteady pulsation intensity of the flow field.At the exit of the impeller,the vortex structure falls off periodically and breaks when it hits the tongue.The generation of the rotor/stator interaction of the centrifugal pump was related to the shedding of the vortex structure at the exit of the impeller.