本文针对某深度调峰联合循环汽轮机组低压末级叶片断裂故障问题,通过叶片材料和裂纹断口理化检验及试验分析、结合机组深度调峰运行特点,深入分析了叶片断裂故障发生的原因,并给出了相关改进建议。该联合循环汽轮机组低压末级叶片断裂的原因,是由于深度调峰燃气机组长期处于盘车运行的特殊工况,以及盘车转速设置偏高造成低压末级松装叶片叶根部位产生磨损,叶片松动,在高速盘车过程中叶片相互猛烈撞击,造成了叶片叶顶围带及叶片的损伤。在机组启动过程中离心力作用下产生断裂,断裂残骸落入末级动叶和静叶之间,进而对整圈末级叶片造成严重损伤。

Aiming at the fracture of low pressure final stage blade of a deep peaking combined cycle turbine unit, this paper analyzes the causes of blade fracture deeply through physical and chemical inspection and test analysis of blade material and crack fracture, combined with the characteristics of deep peaking operation of the unit, and gives relevant improvement suggestions. The reason for the fracture of low pressure final stage blade of the combined cycle turbine unit is that the deep peaking gas unit is in the special working condition of turning gear for a long time, and the high turning speed setting causes the loose blade of the low pressure final stage to wear out at the root of the blade and loosen the blade. In the process of high-speed turning gear, the blades violently collide with each other, causing damage to the blade tip band and blade. The fracture occurs under the action of centrifugal force during the unit startup, and the fracture debris falls between the final rotor blade and the static blade, causing serious damage to the final blade of the whole circle.

TK221