Non-uniform temperature gradients and thermal stresses produced by a moving heat flux applied on a hollow sphere

Abstract

This work presents numerical analyses of transient temperature and thermally-induced stress distributions in a hollow steel sphere heated by a moving uniform heat source applied on a certain zenithal segment (the heated zenithal segment, Θ H ) of its outer surface (the processed surface) under stagnant ambient conditions. Along the process, the moving heat source (MHS) moves angularly from the first zenithal segment to the last zenithal segment on the processed surface with a constant angular speed, ω, and then returns backward to the first zenithal segment with the same speed. It is assumed that the inner surface is heat-isolated and that the outer surface except the heated segment is under stagnant ambient conditions. The numerical calculations are performed individually for a wide range of thermal conductivity, λ, of steel and for the different Θ H s. The maximum effective thermal stress ratio calculated as per the heat flux intensity (q 0) can be reduced in considerable amounts. By increasing λ(∼75%) and ω(∼63%) the maximum effective thermal stress ratio calculated can be significantly reduced.