超高比转速离心泵的高效设计

Efficient Design of Ultra-High Specific Speed Centrifugal Pump

为研究叶轮结构参数对提升n_(s)在300~450间的超高比转速离心泵设计点效率的影响,以某超高比转速单级单吸立式离心泵为研究对象,选取叶轮出口宽度b_(2)、叶片进口安放角β_(1)、叶片出口安放角β_(2)和叶片包角φ为试验因素,建立L_(9)(4~3)正交试验方案,在0.9Q_(n)~1.1Q_(n)工况内对各方案模型进行数值计算,分析各因素对泵水力性能影响的主次顺序,进而得到叶轮结构尺寸的最佳参数组合。按照最佳尺寸优化叶轮,将优化后的泵外特性试验结果与原型进行了对比分析。结果表明:(1)高效设计时超高比转速离心泵叶轮结构参数对效率影响的主次顺序为φ→b_(2)→β_(2)→β_(1),影响水力性能的主要因素为φ,以便指导超高比转速离心泵的高效设计;(2)确定了高效设计时叶轮结构参数的最优水平组合;(3)优化后泵设计点效率较原型提高约4.2%,高效区扩宽至0.75Q_(n)~1.1Q_(n)工况,效率整体提升2.5%以上;(4) 0.75Q_(n)~1.2Q_(n)工况优化后泵轴功率与原型相比降低5.8%~15.8%,利于节能减排。

In order to study the influence of impeller structural parameters on improving the efficiency of design point of ultra-high specific speed centrifugal pump with n_(s) between 300 and 450,a single-stage single-suction vertical centrifugal pump with ultra-high specific speed was taken as the research object.The orthogonal test scheme L_9(4~3) was established by selecting impeller outlet width b_2,blade inlet placement angle β_1,blade outlet placement angle β_(2) and blade envelope angle φ as test factors.The numerical calculation of each scheme model was carried out in the working condition range of 0.9Q_n~1.1Q_n.The main and secondary sequence of influence of each factor on hydraulic performance were analyzed and summarized,and then the optimal parameter combination of the pump impeller structure was obtained.Finally,the impeller was modified according to the optimal size,and the test results of the external characteristics of the optimized pump were compared with those of the original pump.The results show that:(1) In high efficiency design,the main and secondary order of structural parameters of ultra-high specific speed centrifugal pump on efficiency is φ→b_2→β_(21),and the main factor affecting hydraulic performance is φ;(2) The optimal horizontal combination of impeller structural parameters in high efficient design is determined;(3) After optimization,the pump efficiency of the design point is increased by about 4.2% compared with the original pump,and the high efficiency zone is expanded to 0.75Q_n~1.1Q_n,and the overall efficiency is increased by more than 2.5%;(4) The optimized pump shaft power under 0.75Q_n~1.2Q_(n) condition is reduced by 5.8%~15.8% compared with the prototype,which is conducive to energy saving and emission reduction.