障碍物对轴流泵空化内部流场的影响

The influence of obstacles on the cavitation flow field in the axial-flow pump

空化会影响泵的正常工作和稳定运行,为了探索能够有效抑制轴流泵内发生空化的策略,提出了将矩形流向障碍物布置在轴流泵叶片背面的方法.以比转数700的轴流泵作为研究对象,采用全流道非定常数值模拟,分析障碍物对轴流泵外特性空化性能的影响.结果表明:在设计工况下布置障碍物的改进模型在空化各阶段均能有效减少空泡体积,尤其当空泡发展至障碍物位置时效果最好,空泡体积减少了72.5%;布置障碍物能够提高叶片背面出口压力,限制低压区向出口方向扩张,减小逆压梯度,阻挡轮毂侧发生偏流,梳理空化发展的流线,优化流场结构,抑制空化的发展,并将断裂扬程提升了10.19%.

Cavitation will affect the normal and stable operation of the pump.In order to explore a strategy that can effectively inhibit the development of cavitation in an axial flow pump,a method of arranging rectangular flow obstacles on the back of the axial flow pump vanes is proposed.Taking an axial-flow pump with a specific revolution of 700 as the research object,the influence of obstacles on the external characteristics and cavitation performance of the axial-flow pump was analyzed by using the full-channel unsteady numerical simulation.The results show that,under design conditions,the improved model with obstacle arrangement consistently reduces the cavity volume across all stages,especially when the cavity develops to the position of the obstacle,achieving a reduction in the cavity volume by 72.5%.The arrangement of obstacles increases the pressure at the back outlet of the blade,restricts the expansion of the low-pressure area to the outlet,reduces the adverse pressure gradient,blocks the deflection at the hub side,clears the flow line of cavitation development,optimizes the flow field structure,and inhibits the development of cavitation,consequently increasing the fracture head by 10.19%.