Table of Contents
Journal of Aerodynamics
Volume 2014 (2014), Article ID 458757, 9 pages
http://dx.doi.org/10.1155/2014/458757
Research Article

Impact of Surface Roughness on the Turbulent Wake Flow of a Turbine Blade

Institute of Turbomachinery and Fluid Dynamics, Leibniz Universität Hannover, Appelstrasse 9, 30167 Hannover, Germany

Received 4 September 2014; Accepted 9 December 2014; Published 30 December 2014

Academic Editor: Noor A. Ahmed

Copyright © 2014 K. Mulleners et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Roughened aeroengine blade surfaces lead to increased friction losses and reduced efficiency of the individual blades. The surface roughness also affects the wake flow of the blade and thus the inflow conditions for the subsequent compressor or turbine stage. To investigate the impact of surface roughness on a turbulent blade wake, we conducted velocity field measurements by means of stereo particle image velocimetry in the wake of a roughened turbine blade in a linear cascade wind tunnel. The turbine blade was roughened at different chordwise locations. The influence of the chordwise location of the added surface roughness was examined by comparing their impact on the width and depth of the wake and, the positions and distribution of vortical structures in the wake. Additionally, the friction loss coefficients for different surface roughness positions were estimated directly from the velocity field.