Effect of lean mode of blade trailing edge on hydraulic performance for double-suction centrifugal pump

Abstract

For three-dimensional inverse design of water pump, both blade-loading distribution and stacking condition of high-pressure side are important factors affecting the quality of design. For example, inclined trailing edge of blade can suppress the pressure fluctuation and reduce the sound pressure level and sound power of noise for single-suction centrifugal pump. And the lean mode of blade trailing edge can influence hydraulic performance of pump-turbine in pump mode. However, there is no clear view on the effect of lean mode of blade trailing edge on hydraulic performance for double-suction centrifugal pump. Therefore, three different linear lean modes, namely positive lean(+20°), zero lean(0°) and negative lean(-20°), are adopted to simulate the transient flow field respectively for a middle specific speed double-suction centrifugal pump. Concretely, results show that different lean modes of blade trailing edge have little effect on the external characteristics of the pump, and all three schemes can meet the requirements of basic performance. And in operating range of 0.6Q 0~1.2Q 0, positive blade lean can suppress the jet-wake structure better. In the vicinity of rated condition, both positive blade lean and negative blade lean can suppress the pressure fluctuation to a certain degree. But with the changes of flow rate, the effect of positive blade lean on pressure fluctuation is unstable. In addition, when pumping sediment-laden water, both positive blade lean and zero blade lean are not conducive to improving the anti-erosion performance of the blade, and especially for the positive blade lean. In summary, in order to improve the integrated performance of low and middle specific speed double-suction centrifugal pump, under the condition of guaranteeing good blade-loading distributions firstly, negative lean mode of blade trailing edge is suggested.