出水挡板对射流式自吸泵自吸性能的影响

为了提高射流式自吸泵的自吸性能,选取增设出水挡板的UJM75-2型射流式自吸泵为研究对象,采用试验验证和数值模拟相结合的方法,对导流器背面增设出水挡板后的泵腔内气相过流能力的影响规律进行分析,并根据分析结果进一步研究出水挡板对射流式自吸泵性能的影响机理.研究结果表明:出水挡板上方的出水孔与导流器背面筋板位置关系影响混合流体的出流,存在最佳安装位置;液体由出水孔流向泵腔内,会对泵出口产生冲刷作用,使得气液分离不充分,部分液体进入出水管道,阻碍气体排出;出水孔对称中心线与泵出口中心线夹角为90°时,自吸高度可达8.5 m,3 min即可完成自吸;增设出水挡板前后射流式自吸泵的水力性能变化甚微,可保证运行稳定的条件下提高自吸性能.

Effects of water baffle on self-priming performance ofejecting self-priming centrifugal pump

An ejecting self-priming centrifugal pump of type UJM75-2 with additional water baffle was selected as test model to improve the pump self-priming performance.The influence of the water baffle at the back of the diffuser on gas phase flow capacity in the pump chamber was analyzed by using a combined experimental validation and numerical simulation method.Furthermore,the mechanism that the water baffle influences ejecting self-priming pump performance was studied based on the analytical results.The results indicate that the outflow of the mixed fluid is affected by the relative position between the outlet holes above the baffle and the ribs at the back of the diffuser,and the optimal installation position existes.When the liquid flows to the pump chamber from the outlet holes,it has a scouring effect at the pump outlet,leading to an insufficient gas-liquid separation,and in consequence,a part of the liquid enteres the pump discharge pipe to block the gas to be discharged.When the angle between the symmetric center line of the outlet holes and the center line of the pump outlet is 90°,the experimental self-priming height is up to 8.5 m and the self-priming time is 3 min.The pump with the water baffle shows a little difference in performance in comparison with that without the baffle.Thus,the baffle can improve self-priming performance under stable operational conditions.