变转速工况下汽车冷却水泵内外特性变化规律

Effect of Rotation Speed on the Inner Flow and Performance Characteristics for an Automobile Cooling Pump

以某汽车冷却水泵为研究对象,通过定常流场模拟和试验得到多转速工况下的外特性曲线,二者有较好的一致性:扬程随转速均匀变大,高效区增宽并向大流量区偏移。通过非定常流场模拟获得了不同转速下流道内流线、径向速度和压力脉动等分布特性,并对比分析了蜗壳和叶轮所受轴向力和径向力的变化趋势。结果表明:流体速度值、压力脉动幅值以及受力等随转速有较大变化,说明该泵长期远离高效区运行,存在较大的运行稳定性隐患和节能优化空间。

The performance curves of an automobile cooling pump under multi-speed conditions were obtained by steady simulations and the experiment. Two results were in great agreement with each other： the heads increase evenly with the rotation speed and the high efficient area becomes wider moving towards the larger flow rate. For different rotation speeds,the distribution characteristics of streamlines in impeller,radial speed,and pressure fluctuation et. al were gotten by unsteady simulations. Meanwhile the changes of axial and radial forces in the impeller and the volute were compared and analyzed. The results indicate that the fluid velocity,the amplitude of pressure fluctuation and forces et. al show a great change when the rotation speed varies,which accounts for that this pump works away from the highest efficient point for a long time with a big security risk of operational stability and energy saving optimization potential.