低扬程灯泡贯流泵水力特性及内部流场数值模拟

为了更加深入地研究灯泡贯流泵及其后置导叶的水力性能,采用CFD方法,借助于RNG k-ε湍流模型,应用SIMPLIEC算法,对灯泡贯流泵装置全流道进行了数值模拟,分析了其在4种特殊流量工况点下机组后置导叶的流动特性,研究了灯泡贯流泵的内部流动特征。结果表明:在最优工况点时,泵装置的内部流态较好,水流平直顺畅,导叶的导流作用最好;在小流量工况下,泵叶轮进口处出现了大范围的回流、漩涡区,叶轮出口处出水流的流态紊乱,相邻叶片翼型周围有明显的回流区,后置导叶翼型周围的流态紊乱,存在大范围的不良流态区域;在大流量工况下,叶片周围流态较好,出水流态内的回流区较少,但导叶周围的流态较差。可见,后置导叶对叶轮出口处水流的导流作用明显,偏离最优工况时,导叶区的水力损失较大。

Numerical simulation of hydraulic performance and flow pattern of low-lift bulb tubular pump

To further study the hydraulic performances of bulb tubular pump and the rear guide vanes, computational fluid dynamics (CFD) method, RNG turbulence model and SIMPLIEC algorithm were used to conduct numerical simulation for the full flow passage of the pump. The flow patterns of the rear guide vanes and inner flow pattern of the pump were analyzed under four operation cases. The results show that the flow patterns are fine and there is no any back flow area in the pump and the guide vanes have well flow-guide effect under optimal operation; under low flow rate conditions, a large range of back flow and vortex appear at the pump impeller inlet, and disorder flow pattern is found at the impeller outlet, obvious recirculation areas appear around the blade-adjacent space, and also flow pattern at the rear guide vane manifest as turbulent and with a wide range of adverse flow area; in large flow rate condition, the flow pattern is well at the blade-adjacent area, and back flow is relatively rarely seen at the outlet, however the flow pattern around the guide vane is poor. In general, the rear guide vane has an obvious flow guide effect on the impeller outlet, and hydraulic loss is relatively large at the guide vane area when the pump diverges away from the optimal case.