The Turbulent Boundary Layer on an Axial Compressor Blade

Abstract

Time-mean flow measurements of turbulent boundary layer development on the convex surface of an outlet stator blade in a single-stage axial compressor are presented. There is no evidence of logarithmic wall similarity at blade chord Reynolds numbers from 3 × 104 to 2 × 105, and its absence appears due to the combined effects of low Reynolds number, large positive pressure gradient and rapidly changing boundary conditions. Conventional skin friction laws compare very poorly with experiment. The performance of local equilibrium and entrainment-type calculation methods is examined and serious errors are found to develop at blade Reynolds numbers below 105. The best results are obtained from a lag-entrainment method of Green, Weeks and Brooman, which can be recommended for predicting axial turbomachine blade boundary layers at moderate Reynolds number.