Effect of thermal stress on creep lifetime for a gas turbine combustion liner

The present study investigates the effect of thermal stress on the creep lifetime for a combustion liner in a gas turbine. For the calculation of thermal stress of a combustion liner, 3D-numerical analyses are performed using an FEM commercial code. Actual operating conditions and material properties are also applied for the realistic calculation. As a result, high thermal stress is locally induced in the inlet of the rib-roughened region of the whole combustion liner. That is attributed to the high temperature gradients formed from the large temperature differences between the hot spots and the surrounding low temperature regions. The result is in a good agreement with the actually damaged combustion liner. Moreover, the hot gas side of the inlet of the rib-roughened region appeared vulnerable to creep and the minimum creep lifetime is estimated to be approximately 26,900 h.