Combustion selective temperature dilution

In a gas turbine engine having a hot gas flowing in an annular path partially defined by inner and outer liners of a combustor and inner and outer vane shrouds, said combustor including at its upstream end a plurality of injectors for admitting an original mixture of air and fuel to the upstream end of said combustor for burning of said mixture in said combustor, the improvement comprising:

• a plurality of circumferentially spaced-apart stationary turbine vanes disposed in said hot gas flow path downstream of said combustor, each of said vanes extending radially across said hot gas flow path, the spacing between said vanes forming a gap therebetween;
• a first plurality of circumferentially spaced-apart dilution apertures disposed in said combustor downstream of said injectors, upstream of said turbine vanes and in axial alignment with leading edges of said turbine vanes, for admitting dilution air into said combustor for mixing with said original mixture to promote partial mixing thereof;
• and
• a second plurality of circumferentially spaced dilution apertures for admitting dilution air into said combustor to promote partial mixing with the original mixture, each of said second apertures being smaller in size than said first apertures and each being disposed equidistantly between adjacent ones of said first apertures and in circumferential alignment therewith and in axial alignment with gaps between said vanes;
• said first and second apertures being axially located in a secondary combustion zone of said combustor and upstream of said turbine vanes to induce partial mixing of said dilution air with said hot gases for generating a preselected circumferential temperature gradient in said hot gas for providing a flow of hot gas at a relatively higher temperature through said gaps and a flow of hot gas at relatively lower temperature upon said turbine vanes;
• said first and second apertures terminating at substantially an inner surface of said combustor and being located upstream of said vanes at a position such that dilution air from said first apertures flows over a full length of said leading edges of said vanes.