涡轮盘定心衬套失效模式与疲劳寿命研究

针对涡轮盘定心衬套的结构特点和各工况下的载荷形式,分析了它的失效模式.确定其寿命消耗主要为在高温、高机械负荷作用下的多轴低循环疲劳破坏.通过建立了高压涡轮转子整体分析模型,模拟定心衬套主要工况下的各种载荷和约束条件;定心衬套工作状态的温度场条件是利用相关冷却气流参数进行稳态对流换热仿真计算得到的.采用弹塑性有限元分析方法,计算中充分考虑了高压涡轮转子主要部件的相互影响,获得了定心衬套主要工况下危险点的最大应力应变循环.根据危险点的计算结果,利用不同的低循环疲劳寿命方程对危险点进行寿命预测,并对得到的结果进行分析和比较.研究结果表明,定心衬套的存在两个危险点,一是冷却气孔边受轴向载荷作用,二是衬套内壁后缘倒角处受径向和轴向载荷作用. 

Research on failure mode and fatigue life of centering ring of turbine disk

The failure mode of turbine disk centering ring was analyzed based on its structure feature and all load forms.The study proved that low cycle fatigue on the high temperature and high mechanical loading condition might have a relatively great impact on its fatigue life.The analysis model was set up for simulating all loads and constrained conditions.In addition,the heat transfer of cooling airflow and the centering ring was simulated to obtain the temperature field.The maximal stress-strain cycles on dangerous location of the centering ring was calculated with the elastic-plasticity finite element method.The fatigue life was predicted according to the maximal stress-strain cycles with different life prediction methods,and these different results were compared.The research result shows that there are two dangerous locations on the centering ring,one is cooling hole-edge subject to axial load,the other one is after edge chamfer of the inner face subject to radial and axial loads.