中文摘要：

针对某电站水轮机增容改造后转轮应力水平过高的问题,提出了延长叶片近上冠部分的出口边和添加补强三角块两种解决方案。采用CFD方法对水轮机全流道进行定常流动分析,将所得水压力加载到转轮的有限元模型上进行刚强度分析,获得了两个方案下的转轮最大等效应力值和最大变形量。计算结果表明：原转轮最大应力值出现在额定工况,这是因为叶片中部和出口靠上冠两个区域的正背面压差较大,载荷分布不均匀;额定工况下,两种方案可相同程度地将叶片最大应力值减小14.5%,其中方案A由于叶片出口边跨度增加,叶片最大总变形量要大于方案B;方案B的最大应力值位于三角块斜边与叶片出口边相交的位置,离叶片根部较远,有效地改善了叶片根部的受力;同时,流场分析结果表明：两种改型方案对于各工况下的水轮机能量特性和空化性能影响较小。

英文摘要：

For the problem of excessive stresses in the runner after hydraulic turbine reformation,two solutions are put forward in this paper,which are the extension of the outlet edge of the blade near the crown and applying reinforcing triangular piece. In order to identify the loads acting on the runner,the water flow of whole passage has been investigated by using CFD method. The water pressure was loaded on the finite element model of runner,and rigidity strength analysis was conducted.The maximum equivalent stress and the maximum deformation of runner in two solutions were obtained. The results show that： the maximum stress of the original runner appears in rated condition,because the pressure difference between the pressure side and suction side at the center of blade and outlet of near the crown is very big,thus the distribution of load is uneven. Under the rated condition,the maximum stress of blade decreases by 14. 5% in the same degree in both the two solutions. The maximum total deformation of blade in solution A is greater than which in solution B. The maximum stress is located in the the intersection of triangular piece and blade outlet,which is a little far from the blade root,so the force condition of blade root is improved effectively. At the same time,the flow field analysis results show that energy characteristics and the cavitation performance in the two solutions under various operating conditions is less affected.