负荷调节过程中的混流式转轮流固耦合计算  

FSI computation of a Francis runner during load adjustment

作　　者：王正伟[1] 罗永要[1] 方源[2] 温晓军[2] 

机构地区：[1]清华大学热能系,北京100084 [2]黄河万家寨水利枢纽有限公司,偏关036412

出　　处：《水力发电学报》2005年第4期58-61,共4页Journal of Hydroelectric Engineering

摘　　要：近年来,国内一些大型混流式转轮出现了不同程度的裂纹问题,有关研究认为转轮工作过程中的动应力值偏大是引起转轮疲劳产生裂纹的主要原因。引起转轮产生动应力的水力原因很多,本文分析了负荷调节过程中的转轮动应力特性。采用Newmark算法,进行了某混流式转轮的瞬态流固耦合计算。计算发现较大应力区与实际裂纹出现的部位基本一致,但最大静应力远小于叶片的极限破坏应力。在负荷调节过程中,叶片应力集中区承受的动应力可达45MPa左右,比以前估计的经验值要大。结果表明负荷调节过程中动应力值过大也是叶片过早产生裂纹的水力原因之一。Cracks are occurred in some large Francis turbines in recent years. Researches show that high dynamic stress is the most important cause of the cracks of the runner. Dynamic stress is caused by many hydraulic forces, the dynamic stress of the runner during load adjustment is analyzed in this paper. Transient FSI computation of a certain Francis runner is carried out by Newmark algorithm, it agrees with the distribution of the real cracks, but the maximum equivalent stress is much smaller than the failure stress. The dynamic stress of the stress concentration area is about 45MPa during the load adjustment, which is larger than the experienced data. These results show that oversize dynamic stress during the load adjustment is alsp one of the hydraulic cause of premature cracks.

关 键 词：流体机械 流固耦合 负荷调节 动应力 

分 类 号：TK72[动力工程及工程热物理—流体机械及工程]