燃气轮机中机匣内衬裂纹形成原因分析

Cause Analysis of Crack Formation in TMF Lining of Gas Turbine

对于某型号燃气轮机中机匣支板衬里发生裂纹的事件进行有限元模拟及热应力计算,模拟高温烟气在支板衬里中形成的流场及温差情况,根据温差情况计算热应力,与原材料的物理特性进行比较。计算表明,高温烟气在支板尾端底部形成“真空区”,导致该区域温差较大,所产生的热应力在运行工况不稳定的情况下将会大于材料的抗拉特性,产生裂纹。

The finite element simulation and thermal stress calculation are carried out for the crack of the casing support plate lining in a certain type of gas turbine.The flow field and temperature difference formed by high-temperature flue gas in the support plate lining are simulated.The thermal stress is calculated according to the temperature difference.Compared with the physical characteristics of raw materials,the calculation shows that the high-temperature flue gas forms a“vacuum zone”at the bottom of the tail end of the support plate,As a result,the temperature difference in this area is large,and the resulting thermal stress will be greater than the tensile characteristics of the material under unstable operating conditions,resulting in cracks.