Turbine Blade Surface Roughness Effects on Shear Drag and Heat Transfer

摘要

This work used scaled samples of actual turbine blade surfaces to characterize correlations between turbine surface roughness, friction coefficient, and convective heat transfer rate-parameters which affect an engine's efficiency and the blade's lifes an. For erosion/deposits, friction coefficients up to 250 times higher and convective heat transfer coefficients of up to 150 times higher were found when to compared to a flat plate baseline. Other roughness types (pitting and fuel deposits) yielded less dramatic results. These results did not follow existing friction coefficient-to-heat transfer coefficient correlations, such as the Reynolds analogy. While these analytical and empirical correlations hold for flat plates, they may be inadequate to describe the highly irregular surface roughness found on real in-service turbine blades.