Influence of Blade Tip Surface Roughness on the Performance of a Single-Stage Axial Flow Compressor

Numerical investigations are carried out in a single-stage subsonic axial flow compressor to unravel the influence of blade tip surface roughness on the tip leakage flow characteristics and hence the compressor performance. The studies were carried out at different tip clearance of 0.38τ, 0.77τ, 1.15τ, and 1.54τ and blade tip surface roughness of 0.31ε and 0.62ε. The tip clearance of 0.38τ with blade tip surface roughness of 0.62ε resulted in the highest stall margin and pressure rise of 20.3% and 4.3%, respectively. The compressor blade loading was found to be improved by 5.9% after incorporating the blade tip surface roughness. The isosurfaces of vorticity contour plotted using the Q-criterion showed the reduction in strength of the tip leakage vortex. The tip leakage trajectory was found to be shifted toward the suction surface of the blade for the blade tip with surface roughness. This positive alteration in the tip leakage flow structure led to the improved performance for the blade tip with surface roughness.