Failure analysis in after shell section of gas turbine combustion liner under base-load operation

The present study investigates the failure analysis and the lifetime prediction in the after shell section of gas turbine combustion liner with internal cooling passages called C-channel. To calculate distributions of temperature and stresses, 3D-numerical simulations using FVM and FEM commercial codes are performed. As a result, the discrepancy in thermal expansion between hot and coolant side walls induces high thermal stresses in the welding region and above the divider of the C-channel. Thus, these two regions are much weaker than the other regions. The locations match well to those of thermal cracks in actual gas turbine combustors in service.