Centrifugal compressor

Abstract

A technology for widening the operating range of a high-pressure ratio centrifugal compressor including a vaned diffuser is provided. The solidity of each vane in the vaned diffuser is set to the optimum value at which the region, in which burbles do not occur when the air flows into the diffuser, is wider than the region, in which burbles may occur when the air flows into the diffuser. In addition, the solidity is set in such a manner that the straight line, which extends outward from the inner peripheral edge of the vane at a right angle with respect to the chord of the vane, does not cross the adjacent vane. In this way, formation of a throat between the vanes is suppressed.

1 . A high-pressure ratio centrifugal compressor, comprising:
 a vaned diffuser wherein a solidity of each vane is set in such a manner that a stable air flow region, which is included in a region between the adjacent vanes and in which burbles do not occur when air flows into the vaned diffuser, is wider than an air swirl occurrence region, which is included in the region between the adjacent vanes and in which there is a possibility that burbles occur due to presence of the vane when the air flows into the vaned diffuser.   
   
   
       2 . The high-pressure ratio centrifugal compressor according to  claim 1 , wherein the solidity of each vane in the vaned diffuser is set in such a manner that a throat is not formed between the adjacent vanes. 
   
   
       3 . The high-pressure ratio centrifugal compressor according to  claim 2 , wherein the solidity of each vane in the vaned diffuser is set in such a manner that a straight line, which extends outward from an inner peripheral edge of the vane at a right angle with respect to a chord of the vane, does not cross the adjacent vane. 
   
   
       4 . The high-pressure ratio centrifugal compressor according to any one of  claims 1  to  3 , wherein the solidity of each vane in the vaned diffuser is set in such a manner that a surge margin is equal to or larger than 0.1. 
   
   
       5 . The high-pressure ratio centrifugal compressor according to any one of  claims 1  to  3 , wherein the solidity of each vane in the vaned diffuser is set to a value equal to or lower than 1.5. 
   
   
       6 . The high-pressure ratio centrifugal compressor according to  claim 2 , wherein the high-pressure ratio centrifugal compressor operates properly in a state where a speed of the air flowing into the vaned diffuser reaches a sonic speed. 
   
   
       7 . The high-pressure ratio centrifugal compressor according to  claim 3 , wherein the high-pressure ratio centrifugal compressor operates properly in a state where a speed of the air flowing into the vaned diffuser reaches a sonic sound. 
   
   
       8 . The high-pressure ratio centrifugal compressor according to  claim 1 , wherein the vaned diffuser is used in an extraction engine.