Centrifugal compressor

Abstract

A centrifugal compressor is able to cause air to efficiently flow to an impeller thereof, and enables improvement of operating efficiency. The centrifugal compressor has: a casing having an inlet flow channel and a connection flow channel formed therein, the inlet flow channel having a suction port provided at one place thereof, the connection flow channel being connected to the inlet flow channel; a main shaft inserted in the casing; an impeller fixed to the main shaft and arranged in the inlet flow channel; and an inlet guide vane unit having a plurality of inlet guide vanes arranged upstream of the impeller of the inlet flow channel. In the inlet guide vane unit, an arrangement interval between inlet guide vanes at a suction port side is narrower than an arrangement interval of inlet guide vanes at a side opposite to the suction port side.

1 . A centrifugal compressor, comprising:
 a casing having an inlet flow channel and a connection flow channel formed therein, the inlet flow channel having a suction port provided at one place thereof, the connection flow channel being connected to the inlet flow channel,   a main shaft inserted in the casing;   an impeller fixed to the main shaft, and arranged in the inlet flow channel; and   an inlet guide vane unit having a plurality of inlet guide vanes arranged upstream of the impeller of the inlet flow channel,   wherein in the inlet guide vane unit, an arrangement interval between the inlet guide vanes at the suction port side is narrower than an arrangement interval between the inlet guide vanes at a side opposite to the suction port side.   
     
     
         2 . The centrifugal compressor according to  claim 1 , wherein in the inlet guide vane unit, arrangement intervals among a first group of the inlet guide vanes that are at an end portion side at the suction port side and that are 25% of all of the inlet guide vanes are narrower than arrangement intervals among a second group of the inlet guide vanes that are at an end portion side opposite to the suction port and that are 25% of all of the inlet guide vanes. 
     
     
         3 . The centrifugal compressor according to  claim 1 , wherein in the inlet guide vane unit, a relation between a maximum value dmax and a minimum value dmin of intervals between the inlet guide vanes is expressed as 0.6≦dmin/dmax<1.0. 
     
     
         4 . The centrifugal compressor according to  claim 1 , wherein in the inlet guide vane unit, intervals between the inlet guide vanes change, with reference to a reference line of a sine function along a rotating direction of the main shaft, in a range of equal to or less than 20% of amplitude of the reference line. 
     
     
         5 . The centrifugal compressor according to  claim 4 , wherein in the inlet guide vane unit, a position where the interval between the inlet guide vanes is the widest is at a position moved to an upstream side in the rotating direction of the main shaft from an end portion opposite to the suction port by an angle larger than 0° and equal to or less than 40°.