Patent ID: 7937951

Claim:
A system for cooling the impeller of a centrifugal compressor, comprising: the centrifugal compressor including an impeller; an annular diffuser supported by an external casing and including an L-shaped annular end-piece that extends downstream and along the impeller of the centrifugal compressor and that is connected downstream to supporting structural components which support a combustion chamber of the turbomachine, the annular end-piece of the diffuser including an upstream portion that extends radially inward from an inlet of the diffuser and a cylindrical portion which is connected to a radially internal end of the upstream portion; and an L-shaped annular metal sheet provided between the annular end-piece of the diffuser and the impeller of the centrifugal compressor and being attached to the annular end-piece of the diffuser, the metal sheet including a radial upstream portion radially extending between the impeller of the centrifugal compressor and the annular end-piece of the diffuser and a cylindrical portion axially extending from a radially internal end of the radial upstream portion of the metal sheet, wherein the metal sheet cooperates with the impeller of the centrifugal compressor to provide a first annular passageway to carry away the air taken from the outlet of the compressor and cooperates with the annular end-piece of the diffuser to provide a second annular passageway to carry away a portion of the air flow coming out of the diffuser, wherein upstream fins are provided between the upstream portion of the annular end-piece of the diffuser and the radial upstream portion of the metal sheet, and wherein downstream fins are provided between the cylindrical portion of the annular end-piece of the diffuser and the cylindrical portion of the metal sheet.