Gas turbine engine combustion apparatus

A gas turbine engine combustion apparatus comprising:

• at least one flame tube defining a combustion chamber of a fuel vaporising type, said at least one flame tube including an upstream end wall having an exterior upstream surface upon which compressed air is discharged to cool the same and an interior downstream surface upon which fuel is directly discharged and vaporised, said at least one flame tube having a primary combustion zone within the combustion chamber downstream of said downstream surface of said upstream end wall;
• a plurality of flow guide ducts operatively associated with and extending through said upstream end wall of said at least one flame tube, said plurality of flow ducts being arranged in at least one circumferential row about said upstream end wall of said frame tube, each of said flow guide ducts including a first limb portion positioned on said exterior upstream surface of said upstream end wall and having an inlet for compressed air and a second limb portion positioned on said interior downstream surface of said upstream end wall and having an outlet immediately adjacent to said interior downstream surface of said upstream wall for directing a discrete flow of fluid therefrom directly onto said interior downstream surface;
• and
• fuel ducts positioned entirely on the exterior of said flame tube and associated with said first limb portion of at least some of said flow guide ducts for injecting fuel into the flow of compressed air therein to provide a fuel and air mixture, each of said fuel ducts having orifice means positioned at the upstream end of the said associated first limb portion for injecting fuel into the flow guide ducts, said first limb portion positioned on said exterior upstream surface of said upstream end wall having an elongated length which coupled with positioning of said orifice means of said fuel ducts in the upstream end thereof sufficient to enable fuel and air flowing therethrough to be substantially fully mixed before flowing into said second limb portion, said second limb portion having a short length extending a small amount into said flame tube so as to minimize area for vaporisation of the fuel and air mixture prior to discharge from the outlet of said second limb portion directly onto said interior downstream surface of said stream end wall where the fuel is vaporised prior to burning in the primary combustion zone of said flame tube.