非光滑表面叶片对离心泵水力性能的影响研究

Study on influence of non-smooth surface blade on hydraulic performance of centrifugal pump

为了提升离心泵的水力性能,分析了BMS叶片对离心泵性能的影响,以及其在不同流量下的减阻率、内部压力、速度以及壁面剪切力,研究了非光滑表面叶片提升泵水力性能的机理。首先,参照螃蟹上壳表面特征,在离心泵叶片上构建了仿生微球结构;然后,基于CFX,采用RNG k-ε湍流模型对其进行了数值模拟,对比分析了光滑表面与仿生微球表面叶片在各流量下的扬程与水力效率,探究了仿生微球表面水力效率增加率与减阻率的关系;最后,分析了不同流量下微球结构对泵内流体压力、速度以及叶片壁面剪切力的影响。研究结果表明:采用仿生微球结构对离心泵扬程提升率最大为2.5%,其中,在0.6倍额定流量处的提升水力效率表现最好,在0.8~1.4倍额定流量处的水力效率略微降低,水力效率增加率与减阻率变化趋势一致;微球结构使流体旋转失速得到了改善,并破坏了流体涡结构,同时,微球结构使流体压力分布更加均匀,叶片壁面剪切力更低。

In order to improve the hydraulic performance of centrifugal pump,the influence of BMS blades on the performance of centrifugal pump,as well as its drag reduction rate,internal pressure,velocity and wall shear force under different flow rates were analyzed.The mechanism of hydraulic performance of non-smooth surface blade lift pump was studied.Firstly,referring to the surface characteristics of the crab s upper shell,the bionic microsphere structure was constructed on the centrifugal pump blade.Then,based on CFX,the RNG k-εturbulence model was used for numerical simulation,and the head and hydraulic efficiency of the smooth surface blade and the bionic microsphere surface blade at different flow rates were compared,and the relationship between the increase rate of hydraulic efficiency and drag reduction rate on the bionic microsphere surface blade was explored.Finally,the influences of the microsphere surface on the fluid pressure,velocity and the wall shear force on the blade at different flow rates were analyzed.The results show that the maximum lift rate of centrifugal pump head is 2.5%by using biomimetic microsphere structure,and the hydraulic efficiency is the best at 0.6 times rated flow,and the hydraulic efficiency decreases slightly at 0.8~1.4 times rated flow.The increase rate of hydraulic efficiency is consistent with the change trend of drag reduction rate.The microsphere structure improves the rotating stall and destroys the vortex structure of the fluid.At the same time,the microsphere structure makes the fluid pressure distribution more uniform and the blade wall shear force lower.