Area control insert for maintaining air flow uniformity around the combustor of a gas turbine engine

Claim 1

In a gas turbine engine of the type having a combustion apparatus which includes spaced apart inner and outer annular liners defining a combustion chamber therebetween, inner and outer converging cowl portions extending from the forward ends of the respective liners wherein the inner cowl portion diverges more rapidly than the outer cowl portion, an outer wall spaced apart from the outer liner and cowl defining an outer flow passage thErebetween and an inner wall spaced apart from the inner liner and cowl defining an inner flow passage therebetween, improved flow field uniformity is provided by an area control insert comprising: a circumferentially and longitudinally extending wall having a plurality of circumferentially spaced, arcuate segments attached to the inner cowl portion wherein; the major inside surface of the segmented wall is spaced apart from the inner cowl portion so as to constrict the effective cross-sectional area of the forward portion of the inner flow passage, the forward end of the segmented wall is preferably flared in an outward direction into the inner cowl portion in order to maintain a smooth and uniform streamlined flow field over the forward edge of the wall, and the aft end of the wall terminates in a blunt edge so as to provide for the rapid uniform diffusion of air flow passing thereover, thereby providing a uniformly reduced velocity flow field which minimizes the tendency for the air flow to separate from the inner liner at random locations.