Coating roughness impact on the combustion chambers life of the turbo engines

Abstract

The objective of this study is to determine the impact of the convective heat transfer coefficient and the heat conduction coefficient on the metal temperature by studying heat conduction in the base metal and the coating under hot gas convection as well as the cooling flow using analytical methods. Increasing the convective heat transfer results in lower conduction of the coating that is necessary to maintain the metal temperature at the determined level. The surface roughness of the coating is therefore an influential factor in determining metal temperatures and plays a significant role in the lifespan of the hot sections of turbo engines. This phenomenon is numerically studied for the SGT-100 combustion chamber and the results demonstrate that the roughness can considerably increase the wall heat flux of the combustor. This means that the coating should be manufactured so that the coating surface has a lower roughness level. Otherwise, the higher heat flux will cause damage to the combustion chamber.