Modelling of Thermo-Mechanical Fatigue in an Aeroderivative Gas Turbine Blade Made of Inconel 738LC

Abstract

The hot gas section of the gas turbine engine, especially the blades, are usually subjected to high thermal and mechanical loading, as a result su er thermo-mechanical fatigue. The design process usually involves appropriate selection of the turbine blade materials, it is therefore necessary to carry out thermo-mechanical fatigue studies on gas turbine blades to predict blade life. This study models the thermo-mechanical fatigue on gas turbine blade made of nickel based super alloy IN738LC. Simulink was used to develop thermal models to compute the heat transfer coe cient on the cold and hot sides of the blade, and a stress model to compute the centrifugal tensile stress. The heat transfer coe cients, Reynold’s number, and Stanton number at di erent velocities on the hot and cold section of the blade was obtained. The relationships between the Heat transfer coe cient and the Reynold’s number with the change in velocities at the hot and cold sections of the blade was also established. The stress model computed the centrifugal tensile stress acting on the blade at 31.41GPa.The heat transfer and stress models are therefore necessary for TMF calculations to predict the creep life of the blade to prevent engine failure.