The effect on non-uniform surface roughness on the aerodynamics of a turbine blade is investigated. Surface roughness on airfoils has a significant impact on total energy loss due to skin friction and typically leads to an increased thermal loading. In the present research project, investigations are supposed to be carried out experimentally. For this a blade must be designed, which accommodates the contradictory requirements of aerodynamics and manufacturing the sections of surface roughness. A fully automatic design process based on a genetic algorithm is developed and results are shown. The designed blade sufficiently fulfills the given requirements.
A numerical study, using a low-Reynolds approach, is performed to investigate the influence of non-uniform roughness applied to different positions on the suction side of a high pressure turbine blade. It is shown that roughness applied at the leading and trailing edge does not significantly influence the flow whereas roughness at 20% cord length and at midchord induce transition. Especially surface roughness at 20% chord length shows a strong correlation to the change of total pressure loss.