Effects of Surface Roughness on Pressure Distribution and Boundary Layer Over Compressor Blades at High Reynolds Number in a Two-Dimensional Cascade

摘要

In this evaluation of the effects of surface roughness on the pressure distribution and boundary layer over compressor blades, the cascade consisted of seven NACA 65-A506 airfoils with a two inch chord and an aspect ratio of one. The blades were set in the test section at an angle of attack of 15 deg. The test section unit Reynolds number for the evaluation was in excess of two million/foot. Changes to the cascade blade pressure distribution were minimal for moderate average roughness (Ra=24.8 microns) to low average roughness values (Ra=.18 micron), except for pressures near the leading edge which were more pronounced. The pressures near the leading edge which were more pronounced. The pressure distribution for a blade surface roughness of 53.8 microns differed considerable from the baseline case. The cascade test blade experienced laminar flow separation with turbulent reattachment at moderate to low roughness levels, and fully turbulent flow at high roughness levels. The blade suction surface boundary layer thickness increased with roughness values but was most responsive to the transition from laminar to turbulent flow.