Computationally Efficient FE-Models for Simulating the Forced Air Cooling of Turbine Discs

A big issue in finite element simulations is the trade-off between computational costs and accuracy. The present contribution is devoted to FE simulation of the cooling process of turbine discs made out of nickel-base alloy 718 after forging. A fully three dimensional thermal model is compared to an axisymmetric simulation. A sensitivity study with respect to the influence of boundary conditions is performed; in particular, reflection and back radiation from surrounding walls and neighbouring discs, thermal contact to the cooling track and convection heat transfer on horizontal as well as inclined areas of the disk surface. The influence of air speed is estimated by computational fluid dynamics. In conclusion, some guidelines for obtaining a computationally efficient, yet sufficiently accurate FE-model for the cooling process are given.