Patent ID: 6220035
Filing Date: 2001-04-24
Classification: F02C,F05D,F23R,Y10T

Abstract:
A gas turbine engine comprising:a compressor providing pressurized air;a turbine for expanding a hot gas;a combustor disposed between the compressor and the turbine; said combustor comprising;a combustion chamber defined by a combustor wall;a plenum circumscribing the combustor wall and receiving pressurized air from the compressor;at least one premixed injector for injecting a lean fuel and air mixture into the combustion chamber, the premixed injector having an igniter for igniting said fuel and air mixture to initiate the formation of a hot gas that flows from the premixed injector exit into the combustion chamber forming a rotational flow of said hot gas in said combustion chamber;at least one pilot injector disposed in said combustor wall upstream, with respect to said rotational flow, of the premixed injector's exit for injecting fuel into the combustion chamber, whereby upon entering the combustion chamber the fuel ignites to form a fuel rich zone in said rotational flow that envelops the lean mixture exiting said premixed injector and stabilizes the combustion process;a dilution zone just upstream of said turbine, the dilution zone receiving a portion of the air in said plenum through at least one dilution hole;a bypass system for controlling the flow of the remaining portion of said air in said plenum to the premixed injector and the dilution zone, said bypass system including a first conduit extending from the plenum; a second conduit in fluid communication with the first conduit and the premixed injector; a third conduit in fluid communication with the first conduit and the dilution zone; and a valve disposed between the first, second, and third conduits for directing the flow of air from the plenum to the premixed nozzle and the dilution zone,said valve comprising a housing having a first port connected to the first conduit, a second port connected to the second conduit and a third port connected to the third conduit, and a crescent shaped valve rotor rotatably mounted to the housing, said valve having an exchangeable orifice plate mounted in the third port.