Abstract: A combustion process for burning fuel in a combustion chamber is provided. The process includes supplying fuel and air to a burner, the amount of air supplied being at least as much as required for stoichiometric combustion of the fuel and subsequent dilution of the combustion process. The process also includes injecting the fuel and all the air from the burner directly into the combustion chamber in a substantially unmixed state as a fuel stream within an air stream. Fuel is injected from a nozzle, which is nested within an air nozzle. The fuel nozzle ejects a fuel stream of such thickness that the fuel burns in the combustion chamber as a diffusion flame with a high surface-to-volume ratio at or close to the stoichiometric fuel/air ratio. The flow of air through the air nozzle is subject to the venturi effect.

Abstract: A gas-turbine engine combustion system comprises a plurality of combustors interconnected by crossfire tube assemblies adapted to pass an ignition flame from an ignited combustor to another combustor on start-up of the engine. Each crossfire tube assembly comprises a cooling air inlet for introducing air into the assembly to film-cool its inner, ignition flame-facing surface, and a cooling sleeve surrounding the crossfire tube assembly in the region in which it opens into the combustor. The cooling sleeve directs the cooling air so as to cool the outer surface of the assembly, the inside of the sleeve and the inside surface of the combustor wall adjacent the cooling sleeve.