遠心圧縮機特性に及ぼす流路表面あらさの影響

概要

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The influences of the surface roughness of a centrifugal compressor on its performance characteristics were examined. The experiments were conducted by varying the surface roughness within the impeller flow channel as well as Reynolds number. The surface roughness of the pressure, sucsion and hub side walls was varied by means of sticking the sand of a difinite grain size onto the walls, while that of the shroud side wall was roughened by machining it with a lathe. On the other hand, the Reynolds number was varied by changing air pressure in a closed circuit of ducts containg the compressor. The following conclusions were obtained from the result, the efficiency of the compressor gradually decreased as the surface roughness increased, and the reduction of the efficiency amounted to about 5 % when the relative surface roughness increased from 3.8×10^<-3> to 14.0×10^<-3>; friction loss generated within the impeller flow channel could be affected by the flow separation in the boundary layer as well as by the surface roughness; the larger the flow coefficient is, the larger the rate of reduction in the compressor's efficiency is in proportion to the surface roughness; and the critical Reynolds number for the flow inside the compressor could be evaluated by adopting the Schlichting's equation.
明治大学の論文