Evaluation of thermal loadings to ameliorate stress in a rotating disk

For the purpose of safety design of a turbine disk, the fundamental termoelasticity mechanics associated with the thermal loadings imposed on the inner and outer surfaces of a rotating disk have been studied theoretically and numerically. The relationship between the stress level and the thermal boundary loadings was obtained theoretically to identify the existence of four possible stress states of the disk. Then, the computational fluid dynamics and finite element simulations were carried out to validate the theoretical analysis. Results showed that the existence and extent of the four stress states were governed by the thermal loading combination (Q_e - Φ) on the inner and outer surface, respectively, and then their regimes had been delineated. After the thermal loading design was employed, the maximum equivalent stress against the conventional model (Φ = 0) had fallen, except in some cases of state 4. Hence, the thermal loadings on the boundaries of the disk should be designed in an adequate range in order to ameliorate the maximum equivalent stress of a turbine disk. Otherwise, the maximum operating stress would be larger than the one in the conventional model and then the failure probability would be increased.