Effect of Surface Roughness of Impeller Channel in Centrifugal Compressor on Its Performance 901632
Influences of the surface roughness of a centrifugal compressor on its performance were examined. The experiments were conducted by varying the surface roughness within the impeller channel as well as Reynolds number. The surface roughness of the pressure, suction and hub walls were varied by means of sticking the sand of a definite grain size onto the walls, while that of the shroud wall was roughened by machining it with a lathe. Reynolds number was varied by changing air pressure in a closed circuit of duct containing the compressor.
Efficiency of the compressor decreased gradually as the surface roughness was increased, and the reduction of the efficiency amounted to about five percent when the relative roughness was increased from 3.2X10-3 to 14.0X10-3.
Shifting of the critical Reynolds number was not affected so much through the variation of the roughness.