轴流泵在不稳定区(马鞍区)运行时,叶轮进口存在回流区,水泵效率低、机组振动加剧,严重时将造成机组结构破坏.在轴流泵叶轮进口设置5种挡板方案,采用商用软件ANSYS CFX,分别对不同的挡板方案进行了三维不可压湍流数值模拟.计算结果表明,挡板与叶轮进口的距离是影响小流量工况水泵性能的主要因素,其中方案3为最佳方案.叶轮进口的轴面流场表明,挡板能抑制小流量工况水泵进口处的回流,降低叶片吸力面的压力,增加叶片的升力,从而有效地提高小流量工况的水泵运行效率.%The recirculation flow exists at the inlet of the impeller when the axial-flow pumps operate at the low flow rate. At this condition, the pump efficiency falls down and the pump system vibrates seriously, sometimes leads to structural damage, so the pump should avoid operating at this unstable condition. Five schemes with different baffles at the inlet of axial-flow pump impeller were presented. 3-D incompressible flow fields, for different baffle schemes, were simulated by using the commercial software ANSYS CFX. The computed results showed that the distance between the baffles and the impeller was the key factor that influences the performance of axial-flow pumps at the condition of low flow rate. Among these five schemes, scheme No. 3 was the preferred plan. The flow field at the meridional plane shows that baffles could reduce the backflow at the inlet of axial-flow pump, reduce the pressure at the suction side and increase the lift of the blade, so as to increase the efficiency of axial-flow pumps at the condition of low flow rate.
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