离心泵平衡孔和背叶片对轴向力特性影响

为研究平衡孔和背叶片对低比转数离心泵轴向力特性的影响,选用一台IS80-50-315型离心泵为研究对象,分别对只有平衡孔、只有背叶片及二者皆有、皆无4种方案进行试验与数值分析.结果表明,背叶片对泵水力性能的影响大于平衡孔,且对泵能量损耗起主导作用.在额定工况下,前泵腔内液体压力沿径向具有“阶梯型”变化规律,后泵腔内液体压力近似线性增大,平衡腔内液体压力随流量变化几乎呈直线分布趋势;同一台试验泵中,平衡孔对前泵腔和平衡腔内液体压力影响更大,背叶片对后泵腔内液体压力降低效果更佳.叶轮加背叶片后所受扭矩明显增大,仅有平衡孔时扭矩稍有增加.全流量工况下平衡孔对轴向力的平衡能力优于背叶片;两者共同存在时,平衡轴向力效果最差.

Effect of balance holes and back blades on axial thrust of centrifugal pump

In order to investigate the effect of balance holes and back blades on axial thrust of the low specific speed centrifugal pumps, the IS80-50-315 centrifugal pump was chosen as the research object. Four different projects were tested and numerically analyzed, which included the balance hole, the back blade and both of them and neither of them. The results show that the influence of the back blades on the hydraulic performance of the centrifugal pump is greater than that of the balance hole, and it plays a leading role in energy loss of centrifugal pump. Under the rated operating mode, the fluid pressure in front pump chamber radially changes with ladder shape, the fluid pressure in the rear pump chamber approximately linearly increases, and the fluid pressure in balance cavity almost shows linear distribution with the change of flow. In the same test pump, the balance hole has greater influence on the liquid pressure in the front pump cavity and the balance cavity. The back vane has a better effect on the pressure drop of fluid in the back-pump cavity. At the same time, the torque is obviously increased when back blades are added on the runner, but the torque of the runner is slightly increased with only balance holes. The balance hole has better balance effect on axial force than back blades under the full flow conditions, and the ability of balancing axial force is the worst when both of them exist.〓