混流式转轮叶片裂纹原因分析及处理技术探讨

通过对国内几大典型电站混流式转轮叶片出现裂纹原因及处理结果的分析,认为混流式转轮叶片的结构、刚度、强度、材质特性、装焊质量和运行工况的科学设定是避免叶片裂纹产生的基本或明显因素;而叶片出口卡门涡频率与叶片固有频率关系的正确设定是消除裂纹产生与发展的潜在或促进因素.因而应用CFD软件对叶片进行水力设计与分析的同时,对卡门涡频率和叶片固有频率进行专项分析、计算,在确认两者无约数关系的条件下,给出较佳的设计方案.

Discussion on cracking origin of Francis turbine blades and its treatment technique

After analyzing the cracking reason of the blades on the runner of Francis turbine installed in several domestic large-scale power plants and its treatment technique, it is recognized that the scientific determination of the configuration, stiffness, strength, material properties, welding quality, and operation condition is the basic and effective measure to avoid the happening of the cracking on the blades, and properly setting the relationship between the frequency of Karman vortex street behind the blades natural frequency of the blades is the potential and advancing factor to eliminate the happening and propagation of the cracks. Therefore, the software CFD is adopted to conduct the hydraulic design and analysis of the blades, accompanied with the special analysis and evaluation of the frequency of Karman vortex street and natural frequency of the blades to confirm that there is no common divisor between them, so that an optimal design can be obtained.