Patent ID: 7937944

Claim:
A system for ventilating a combustion chamber wall in a turbomachine comprising: a centrifugal compressor including an impeller; a diffuser including an annular end-piece with a substantially L-shaped section that extends downstream and along the impeller of the centrifugal compressor so as to present a radial annular passageway for communicating a flow of air between a radially external end of the diffuser and an outlet of the compressor; an annular combustion chamber; and an annular case arranged radially between the combustion chamber and the end-piece of the diffuser and extending axially from the diffuser to the vicinity of the outlet of the combustion chamber and of the downstream end of the end-piece of the diffuser, the case including a radially external wall of revolution which cooperates with a radially internal wall of the combustion chamber to guide an air flow coming out of the diffuser, and a radially internal wall of revolution which cooperates with the end-piece of the diffuser so as to provide an annular channel therebetween for air coming out of the diffuser to pass through, wherein the end-piece of the diffuser includes an upstream radial portion which extends radially inward from an inlet of the diffuser and a cylindrical downstream portion which extends downstream from the upstream radial portion, and wherein the internal wall of revolution of the case includes an upstream annular portion which extends radially inward and substantially parallel to the upstream radial portion of the end-piece of the diffuser, an intermediate cylindrical portion which extends axially, and a frustoconical downstream annular portion which extends downstream and radially outward.