Variable area cooling passages for gas turbine burners

Claim 1

In a combustion chamber for a gas turbine engine: an outer wall portion forming the outer casing of said combustion chamber; an inner wall portion positioned inside said outer wall portion; one of said wall portions containing a plurality of peripherally spaced recesses about its surface, the separation between said recesses being equal to or larger than the width of each said recess; said inner and outer wall portions being of substantially constant thickness, the said one wall portion abutting the said other wall portion along the separations between the recesses in said one wall portion whereby said recesses form a plurality of longitudinally extending closed passages with the surface of said other wall portion, each of said passages being substantially rectangular in cross section, the width of each said passage being constant and the depth of each said passage being varied along its longitudinal axis to vary the crosssectional area of each said passage along its longitudinal axis; a source of cooling fluid for said combustion chamber, means for causing at least a portion of said cooling fluid to flow through said passages to provide cooling to said walls portions, the velocity of said fluid being varied with variations in the cross-sectional area of said passages to provide a variable rate of cooling and produce a substantially uniform temperature profile along the walls of said chamber.