不同叶型对混流式核主泵叶轮出口能量分布的影响

Influence of blade thickness profile on energy distribution at impeller outlet of mixed-flow nuclear reactor coolant pump

为了进一步探索叶片对液流的推动机制,采用数值计算方法对具有不同叶型的混流叶轮水力性能、出口能量分布特性和内部流动进行研究,得到叶轮出口动能和压能,并将其求和得出总能量的分布规律,且求出轴向动能和径向动能及其比例,并从流动分解角度分析流体对不同叶型的绕流情况.结果表明:该混流式叶轮在进口至出口方向叶型为仿翼型时比前后盖板方向叶型为仿翼型时具有更好的能量性能;当前后盖板方向叶型为仿翼型时,最厚位置靠近后盖板侧,叶轮的水力性能相对较高;叶轮出口能量中压能占较大数值比例,且叶片轴、径向做功比例和叶型存在一定关联关系;进口至出口方向叶型为仿翼型时,对轴、径2个方向的流动均具有良好的适应性,而前后盖板方向为仿翼型变化时只能在1个方向上近似翼型绕流.

In order to clarify mechanism of blades acting on a liquid,the hydraulic performance,energy distribution properties at impeller outlet and internal flow in mixed-flow impellers with different blade thickness profiles were investigated by using numerical methods. The kinetic and static pressure energies as well as the total energy at impeller outlet were obtained. In addition,the total energy was decomposed into radial and axial components,and their proportions to total energy were calculated.The fluid patterns around blades with different thickness profiles were analyzed. The results show that the streamline-wise variable blade thickness profiles can result in a better hydraulic performance than the span-wise variable blade thickness profiles,especially in the case that the maximum thickness occurs near the hub. The total energy is almost the static pressure energy at impeller outlet,but it has a similar distribution feature to kinetic energy. The radial and axial energy proportions have a relationship with both blade thickness profile and pump working condition. For the streamline-wise variableblade thickness profiles,the blade can adapt to the flow in both the axial and radial directions. For the span-wise variable blade thickness profiles,however,the blade can adapt to the flow in one direction only.