Surface cooling system

Claim 1

Liner structure for a hot gas duct in a gas turbine engine or the like, comprising: (a) substantially coaxial inner and outer walls having respective upstream and downstream ends and defining a duct for conducting hot gas from an upstream end to a downstream end thereof; (b) said inner and outer walls circumferentially joined near respective upstream ends thereof and spaced downstream thereof to define a circumferential plenum having a closed upstream end and an open downstream end defining a circumferential opening between respective downstream ends of said inner and outer walls; (c) a plurality of axially extending wall members disposed within said plenum between said inner and outer walls dividing said plenum into a corresponding plurality of circumferential plenum segments; (d) means, in said outside wall defining an inlet into each respective plenum segment, for selectively conducting gaseous coolant into each said respective plenum segment; and (e) said inner wall terminating at the downstream end thereof near and downstream of said circumferential opening, said downstream end of said inner wall being spaced from said outer wall a preselected distance to define a circumferential louver at each said plenum segment for directing said gaseous coolant along the surface of said outer wall defining said duct downstream of each said louver.