副叶片对双吸离心泵口环泥沙磨损的影响分析

Influence of back blade on sediment erosion of impeller ring in double suction pump

采用欧拉—拉格朗日多相流模型,对双吸式离心泵内的水流和泥沙颗粒运动进行了模拟,分析了不同型式的副叶片对口环磨损的影响,分析结果表明:口环附近流速较低,对泥沙颗粒的挟带能力较弱,造成口环附近泥沙浓度远远高于水中平均泥沙浓度,导致了口环的快速磨损;采用副叶片可以提高口环附近水流相对速度的径向分量,防止泥沙颗粒在口环附近区域淤积,从根本上减少泥沙对口环的磨损;副叶片的存在会引起额外的圆盘摩擦损失,导致装置效率下降,采用后弯式短副叶片可以有效减少摩擦损失。

An Euler-Lagrange multiphase flow model was used to simulate water flow and sediment movement in a prototype double-suction centrifugal pump, and the influence of back blade on sediment erosion of impeller ring was analyzed. The results show that flow velocity near the impeller ring is too low to move sediment out of the spacing between the impeller and easing, and that high sediment concentration near the ring is a major contributor to ring erosion. Back blade significantly increases radial component of relative velocity and hence reduces sediment concentration there, while it increases impeller side friction and causes a decrease in pump efficiency. Among the three types of back blades adopted in this study, the short backward blade is the most effective.