초록 ▼

Combustion equipment for a gas turbine engine operating on the pre-mix lean combustion bases comprises a flame tube having a plurality of alternately arranged main and pilot air ducts each having a respective fuel injector and receiving axially directed air from downstream of part span outlet guide

Combustion equipment for a gas turbine engine operating on the pre-mix lean combustion bases comprises a flame tube having a plurality of alternately arranged main and pilot air ducts each having a respective fuel injector and receiving axially directed air from downstream of part span outlet guide vanes. The fuel and air in each duct are substantially pre-mixed before entry into the flame tube and the outlets of the pilot ducts direct the fuel and air mixture into the recirculation zone in a single vortex. At engine idle the air fuel ratio (AFR) is substantially stoichiometric to prevent the formation of unburnt hydrocarbons (UHC) and carbon monoxide (CO). As the engine accelerates the fuel flow to the pilot air ducts remains near constant so that the AFR in the re-circulation zone progressively weakens, and fuel is introduced into the main air ducts, the outlets of which direct the air fuel mixture into the flame tube with a substantial downstream component. The equivalence ratio of the main air fuel mixture is kept below 0.7 to keep NOx emissions at an acceptable level. Air direct from the engine compressor with a large swirl component is used to cool the flame tube walls with a high degree of effectiveness due to the scrubbing action of the air. Ducting for outer dilution air and bleed air can also be provided interdigitated with the main and pilot air ducting, and the flame tube can also have a catalyst block which allows the re-circulation zone to run weak at engine idle without excessive UHC and CO being produced.

대표청구항 ▼

Combustion equipment downstream of a compressor of a gas turbine engine, said combustion equipment comprising: a flame tube; an air casing in which said flame tube is located, said air casing being divided into two separate regions, each of said regions arranged to receive compressed air from said c

Combustion equipment downstream of a compressor of a gas turbine engine, said combustion equipment comprising: a flame tube; an air casing in which said flame tube is located, said air casing being divided into two separate regions, each of said regions arranged to receive compressed air from said compressor of said gas turbine engine; air ducting in one of said regions, said air ducting including angularly arranged pilot air ducts having pilot fuel injectors in upstream ends thereof alternating with angularly arranged main air ducts having main fuel injectors in upstream ends thereof, said pilot air ducts having downstream ends with outlets opening into said flame tube and arranged to direct a fuel/air mixture transversely into said flame tube to form a single recirculation vortex in a recirculation zone, said main air ducts having downstream ends with outlets opening into said flame tube and arranged to direct a fuel/air mixture into said flame tube with a substantial component of direction downstream of said flame tube; flow directing means immediately upstream of said air ducting to direct air substantially axially into said air ducting; and cooling air ducting in the other of said regions of said air casing, said cooling air ducting being arranged to receive compressed air having a swirl component from said compressor, said cooling air ducting including at least a part of the upstream end of said flame tube.