叶片包角对泵作透平水力径向力的影响

Effect of blade wrap angle on the radial force of centrifugal pump as turbine

为研究叶片包角对离心泵作透平瞬态水力径向力的影响,以一台蜗壳式离心泵反转作透平为研究对象,保持叶轮和蜗壳其他几何参数不变,应用计算流体力学软件CFX对泵作透平全流道内多工况瞬态流动特性进行数值计算,并对预测性能进行了试验验证。结果表明,作用在叶轮上的径向力,当叶片包角增加超过一定值时小流量工况下减小不明显,而大流量下减小显著。随包角增加,作用于蜗壳上的径向力减小并向第四象限偏移。叶片包角存在一个合适的取值范围,使得泵作透平运行在大流量工况下时径向力较小。

In order to study the effects of blade wrap angle on the radial force of a centrifugal pump as turbine, a single volute vaneless counter-rotating centrifugal pump was chosen as the research object. In the study, the blade wrap angle was varied from 100° to 115° and 130°, while the volute and other geometric parameters were kept constant. The transient flow characteristics under various operating conditions in the whole flow passage of the centrifugal pump as turbine were studied numerically by using the computational fluid mechanics software CFX. The results show that when the blade warp angle increases beyond a certain value, the radial force on the impeller reduces slightly at low flow rates and obviously at high flow rates. The radial force on the volute reduces and moves to the fourth quadrant as the blade warp angle increases. The blade warp angle should be within a suitable range to ensure a lower radial force level at higher flow rates.