Gas turbine combustion chambers

Abstract

A combustion chamber for a gas turbine made up of outer and inner side walls, the combustion chamber being received in a casing so as to define an annular space between the combustion chamber and the casing in which there flows air for combustion, for dilution, and for cooling the combustion chamber, the side walls of the combustion chamber being pierced by a plurality of holes in which bushings of substantially elliptical right section are fixed to define air injection passages for injecting air into the combustion chamber, each bushing having a peripheral wall in which at least one additional orifice is formed opening out into the combustion chamber in the immediate vicinity of the side wall of the combustion chamber in which said bushing is fixed so that the air passing through said orifice flows substantially along said peripheral wall, the peripheral wall of each bushing having at least one groove opening out into the annular space and into which the or each orifice opens out so as to be fed with air and so as to cool the peripheral wall of the bushing.

1 / a combustion chamber for a gas turbine comprising outer and inner side walls interconnected by an end wall, the combustion chamber being received in a casing so as to define an annular space between the combustion chamber and the casing, in which space there is a flow of air for combustion, for dilution, and for cooling the combustion chamber, the side walls of the combustion chamber being pierced by a plurality of holes having respective bushings fixed therein to define air injection passages for injecting air into the combustion chamber, each bushing comprising a peripheral wall in which at least one additional orifice is formed that opens out into the combustion chamber in the immediate vicinity of the side wall of the combustion chamber in which said bushing is fixed so that the air passing through said orifice flows substantially along said side wall, wherein each bushing is of substantially elliptical right section, the peripheral wall of each bushing including at least one groove opening out into the annular space and into which the or each orifice opens out so as to be fed with air and so as to cool the peripheral wall of the bushing:  
     
     
         2 / A combustion chamber according to  claim 1 , wherein each bushing comprises a collar pressed against the side wall of the combustion chamber in which the bushing is fixed so as to match the shape of said side wall.  
     
     
         3 / A combustion chamber according to  claim 1 , wherein the front portion of the peripheral wall of each bushing projects into the inside of the combustion chamber relative to the side wall of the combustion chamber in which the bushing is fixed.  
     
     
         4 / A combustion chamber according to  claim 1 , wherein the front portion of the peripheral wall of each bushing which opens out into the combustion chamber is semi-flush relative to the side wall of the combustion chamber in which the bushing is fixed.  
     
     
         5 / A combustion chamber according to  claim 1 , wherein the front portion of the peripheral wall of each bushing which opens out into the combustion chamber is flush relative to the side wall of the combustion chamber in which the bushing is fixed so as to minimize degradation of the cooling air film.  
     
     
         6 / A combustion chamber according to  claim 1 , wherein the central axis of each bushing coincides substantially with the normal of the side wall of the combustion chamber in which the bushing is fixed.  
     
     
         7 / A combustion chamber according to  claim 1 , wherein the central axis of each bushing slopes relative to the normal of the side wall of the combustion chamber in which the bushing is fixed.  
     
     
         8 / A combustion chamber according to  claim 1 , wherein each bushing possesses a major axis extending substantially parallel to the flow direction of the gas generated by burning fuel.  
     
     
         9 / A combustion chamber according to  claim 1 , wherein each bushing possesses a major axis whose direction is inclined relative to the flow direction of the gas generated by burning fuel.  
     
     
         10 / A combustion chamber according to  claim 1 , wherein each bushing has a plurality of orifices angularly distributed around its peripheral wall.  
     
     
         11 / A bushing for fixing in air injection holes pierced through the outer and inner side walls of a combustion chamber for a gas turbine, the bushing comprising at least a central passage for injecting air and a peripheral wall in which there is formed at least one additional air injection orifice, wherein each bushing possesses a right section that is substantially elliptical, its peripheral wall having at least one groove opening out into a rear face of the bushing and into which the or each orifice opens out so as to be fed with air and so as to cool the peripheral wall of the bushing.  
     
     
         12 / A bushing according to  claim 11 , having a plurality of air injection orifices angularly distributed around its peripheral wall.