Measurements Concerning the Influence of Surface Roughness and Profile Changes on the Performance of Gas Turbines

Abstract

During operation the blading of turbines undergoes certain changes. Corrosion, erosion, and contamination cause deterioration of the surface quality and blade profile changes. As a result, the performance characteristics of the turbine, especially the efficiency, change during operation. Through measurements on a four-stage air turbine with artificially roughened blade surfaces and thinned and thickened profiles which simulate the effects of corrosion and pollution respectively, it has been possible to ascertain the influence of these profile changes on the flow conditions in the turbine. This paper shows the measuring results which are representative of the effects of surface roughness and profile changes.