Thermo-mechanical life prediction for material lifetime improvement of an internal cooling system in a combustion liner

This paper is concerned with heat transfer analysis and life prediction in the after shell section of a gas turbine combustion liner with internal cooling passage. The method in the present study is the process to design cooling systems which enhance the material lifetime as well as the cooling performance. Using this method, we found the major causes of lifetime-affecting thermal damage induced by heat transfer distributions in the internal cooling system of the after shell section. From startup to shutdown, high thermal deformation occurred between the hot and coolant side walls in the welding region, the nearby cooling hole, and above the divider of the C-channel. Three regions were therefore very weak in relation to the thermal cycle. Moreover, these locations were in close agreement with the locations of thermal cracks in an actual gas turbine combustor currently in service.