Rotary machine

Abstract

A centrifugal compressor includes an impeller fixed to a rotary shaft, and a casing accommodating the impeller. The impeller includes a disc-shaped disc portion, a plurality of blade portions provided to be separated from one another in a circumferential direction, and a cover portion facing the disc portion with a gap interposed therebetween and covering the plurality of blade portions from one of two sides in the axial direction. The casing includes a perforated face, which faces the cover portion with a gap interposed therebetween, is provided at an inner peripheral side area in relation to an outer peripheral side end of the cover portion, and is provided with a plurality of holes.

1 - 6 . (canceled) 
     
     
         7 . A rotary machine comprising:
 a rotary shaft;   an impeller that is fixed to the rotary shaft; and   a casing that covers the rotary shaft and the impeller, wherein   the impeller includes a disc-shaped disc portion, a plurality of blades that are provided at one face in an axial direction in which the rotary shaft of the disc portion extends such that the blades are separated from one another in a circumferential direction, a cover portion that faces the disc portion with a gap interposed therebetween and covers the plurality of blades from one of two sides in the axial direction, and   the casing includes a tapered casing face that faces the cover portion with a gap interposed therebetween, wherein   the tapered casing face includes a perforated face which is provided in an area inner than a portion facing to an outer peripheral side end of the cover portion and is provided with a plurality of holes.   
     
     
         8 . The rotary machine according to  claim 7 , wherein
 the perforated face is a slope that is inclined with respect to a face orthogonal to the axial direction.   
     
     
         9 . The rotary machine according to  claim 7 , wherein
 the plurality of holes are formed in a circular cross-section shape and are adjacent to one another.   
     
     
         10 . The rotary machine according to  claim 7 , wherein
 the plurality of holes are formed in a hexagonal cross-section shape and are adjacent to one another.   
     
     
         11 . The rotary machine according to  claim 7 , wherein the holes have a different depth in a circumferential direction about the rotary shaft. 
     
     
         12 . The rotary machine according to  claim 7 , wherein the holes have a different depth in a radial direction about the rotary shaft.