叶顶间隙对汽车水泵压力脉动影响的数值研究

Numerical Study of Pressure Fluctuations on Automobile Pump Considering Tip Clearance

汽车水泵作为汽车冷却系统中的重要部件,对发动机性能有着重要的影响。基于SST k-ω湍流模型,对不同尺寸下叶顶间隙的汽车水泵进行了非定常数值计算,研究了其内部流场和压力脉动特性。结果表明:在不同的叶顶间隙下,泵内流场的压力脉动特性均表现出明显的周期性变化,各监测点压力脉动峰值均出现在叶频处,同时随着叶顶间隙的增大,叶片上和蜗壳内的压力脉动是逐渐减弱的;泵内压力梯度也随着叶轮旋转呈现周期性变化,随着叶顶间隙的增大,叶轮、蜗壳和叶顶间隙上的压力是逐渐减小的;叶轮流道内和蜗壳出口处均出现二次流回流旋涡,随着叶顶间隙的增大,叶轮流道内涡强度减弱,蜗壳出口处涡强度加剧。

As an important component of the automobile cooling system,the automobile water pump has important influence on the engine performance.Based on SST k-ωturbulence model,unsteady numerical calculation of automobile water pump under different sizes of blade tip clearance was carried out,and its internal flow field and pressure fluctuation characteristics were studied.The results show that under different tip clearances,the pressure fluctuation of the pump flow field showed obvious cyclical changes,and the monitoring points of the pressure fluctuation peak occur at the blade frequency at the same time.With the increase of the tip clearance,the pressure fluctuation on the blade and volute was gradually weakened.The pressure gradient in the pump also varied periodically with the rotation of the impeller.As the tip clearance increased,the pressure on the impeller,volute and blade tip clearance decreased gradually.There appeared a secondary flow return vortex in the impeller runner and at outlet of the volute.With the increase of the tip clearance,the vortex intensity decreased and the vortex intensity was intensified at the volute exit.