Reheat combustion apparatus for bypass gas turbine engines

Claim 1

A gas turbine engine having compressor means, combustion equipment and turbine means in flow series for producing a stream of hot gases, a hot gas duct for said stream of hot gases, and a bypass duct adapted to receive some of the air compressed by the compressor means to form a bypass stream, the bypass duct surrounding the hot gas duct and terminating in a downstream end from which the bypass stream is caused to emerge to be mixed with the hot gas stream, a reheat system comprising flame-stabilizing means in the hot gas duct to provide zones of stabilized flow in the hot gas stream, fuel supply means selectively operable to supply fuel to the hot gas stream by injecting it into said zones of stabilized flow, a combined flow-mixing and flame-stabilizing device disposed at the downstream end of the bypass duct, said device causing the bypass stream to mix with the hot gas stream and to provide zones of stabilized flow in the bypass stream and fuel injection means for selectively supplying fuel to said zones of stabilized flow, said flow-mixing and flame-stabilizing device comprising a plurality of circumferentially spaced-apart and obliquely extending longerons adapted to be disposed in the bypass duct so that an upstream point on each longeron lies at a lesser radius than a point downstream thereof, thereby providing a plurality of obstructions in the bypass duct capable of producing wakes in the bypass stream so that a flame immediately downstream of the end of the bypass duct may be stabilized and defining between the obstructions flow passages through which the bypass stream is caused to be mixed with the hot gas stream, the flow-mixing and flame-stabilizing device further comprising a truncated conical member having means defining circumferentially spaced elongate apertures extending substantially the whole length of the member.