变温循环冷气对涡轮导叶寿命影响

Influence of variable temperature circulating air on turbine guide vane life

为提高燃气轮机涡轮导叶的可靠性及其使用寿命,引入变温循环冷气的概念,以某涡轮叶片为例,开展了燃气涡轮叶片热冲击循环疲劳寿命研究,对燃气轮机涡轮导叶进行启-停循环载荷谱下的应力状态的三维流固热耦合有限元分析,针对叶片在变温循环冷气的热冲击应力变化规律,得到叶片在循环中的稳态与过渡态下的温度场、应力场分布,之后对各个计算工况下的叶片结构强度与疲劳寿命进行分析与评估。搭建试验台,对该型燃气轮机涡轮导叶进行定温冷气循环下的热冲击疲劳试验,与有限元分析结果进行比对,得到结论:三维流固热耦合有限元分析所得叶片应力较大区域为叶片尾缘及叶盆中部,与热冲击试验所得破坏区一致,通过改变冷气循环温度可有效地提高叶片热疲劳寿命。

To improve the reliability and service life of gas turbine guide vane,the concept of variable temperature circulating air conditioning was introduced.Taking a turbine vane as an example,the thermal shock cycle fatigue life of a gas turbine vane was studied,and three-dimensional fluid-solid thermal coupling finite element analysis of stress state under start-stop cycle load spectrum of turbine guide vane was carried out.According to the change law of thermal shock stress of the vane in the cold air of the variable temperature cycle,the temperature field distribution and stress field distribution of the vane in the steady state and transition state in the cycle were obtained,and then the structural strength and fatigue life of the vane under each calculation condition were analyzed and evaluated.A test bench was built,thermal shock fatigue test was carried out on the turbine guide vane of this type of gas turbine under constant temperature cold air circulation,and then the test results were compared with the results of finite element analysis,showing that:the large area of turbine van stress obtained by three-dimensional fluidsolid thermal coupling finite element analysis was located at the trailing edge of turbine van and the middle of turbine van basin,consistent with the failure zone obtained by thermal shock test;the thermal fatigue life of vane can be effectively improved by changing the cooling circulation temperature.