Patent ID: 6447241
Filing Date: 2002-09-10
Classification: F04D,Y10S

Abstract:
A method for expanding an operating range of a centrifugal compressor, the centrifugal compressor including a shroud wall extending ahead of an outer periphery of an impeller to provide an air inlet, an annular treatment cavity in the shroud wall and first and second openings on the shroud wall, the first opening providing communication between the treatment cavity and an impeller-side portion of the air inlet, the second opening providing communication between the treatment cavity and a portion of the air inlet located upstream of the impeller-side portion of the air inlet, wherein, during a low-flow-rate operation, part of the air sucked through the impeller is fed through the first opening into the treatment cavity and is discharged through the second opening so as to be circulated, the method, comprising:feeding air into the treatment cavity so as to have a flow within a range from a direction with no whirling component to a whirling direction reverse the rotative direction of the impeller; and discharging the air, which has flowed through the first opening into the treatment cavity, through the second opening as a flow having a direction within a range from a direction with no whirling component to a whirling direction reverse to the rotative direction of the impeller.