Premix combustor assembly

Claim 2

An improved annular combustor for a turbine type power plant having an inner casing and outer casing defining an annular chamber, liner means closed at the forward end and opened at the rearward end which end is directly communicating with the turbine of the power plant disposed in said annular chamber defining a combustion zone, a premix passage formed adjacent the closed end of said liner by said liner and an annular wall surrounding said liner, a baffle at the downstream end of said premix passage having openings whose axis is at an angle relative to the axis of the combustion zone interconnecting said passage with said combustion zone so as to discharge a fuel/air mixture into the combustion zone in a forward to rearward direction with radial component creating local eddies on the downstream side of said openings without incurring large recirculating zones, at least one secondary fuel nozzle in said premix passage for admitting fuel upstream of said baffle when said power plant is operating at high power, at least one primary fuel nozzle operable independently of said secondary fuel nozzle disposed in proximity to the closed end of said liner for admitting fuel in the combustion zone forwardly and radially of the openings in said baffle when said power plant is operating at low power and said secondary nozzle being disposed forwardly and radially relative to said primary nozzle.

Claim 3

An improved annular combustor as claimed in claim 1 wherein said annular wall has a forward end extending in the discharge airstream of the compressor and forming a splitter for a portion of compressor air to be admitted into said premix passage and defining an inlet thereto, and said nozzle in said premix passage being located downstream of said inlet and spaced from said baffle sufficient distance to achieve maximum residence time of the injected fuel without incurring auto-ignition.

Claim 4

The invention according to claim 2 wherein said primary nozzle is mounted on said liner for injecting fuel directly into the combustion zone and wherein said primary nozzle is a nozzle of the pressure atomizing type.

Claim 5

The invention according to claim 3 wherein said primary nozzle is surrounded by a plurality of swirl vanes which flow a portion of the combustion air from the compressor into the combustion zone.

Claim 6

Means for reducing the pollutants emitted from an axial flow gas turbine engine, which engine includes a combustor, a compressor forward of said combustor and a turbine rearward of said combustor, said means comprising: means disposed in said combustor for burning fuel including a first wall means closed at one end defining an annular combustion chamber around the axis of said engine having a combustion zone at the upstream end thereof, said first wall means opened at an opposite end forming an outlet at the downstream end of said chamber for directing combustion products into the turbine; second wall means surrounding a portion of the first wall means and radially spaced therefrom forming an annular premixing passage having an inlet and an outlet and said premixing passage being wholly forward of said passage outlet for receiving air being discharged from the compressor; fuel supply means disposed within said premixing passage for introducing fuel into said premixing passage, the flow of air within said premixing passage atomizing the fuel within the premixing passage, said premixing passage being in gas communication with said combustion zone, baffle means having apertures formed therein disposed across said outlet of said premixing passage for directing the fuel-air mixture from said premixing passage radially across said primary combustion zone toward said other wall of said chamber, said baffle means including a downstream facing surface creating localized eddies within said combustion zone immediately adjacent said downstream facing surface of said baffle means between adjacent openings, and said localized eddies defining stabilization regions for continuous ignition for said combustion zone, at least one secondary fuel nozzle in said premix passage for admitting fuel upstream of said baffle when said power plant is operating at high power, at least one primary fuel nozzle operable independently of said secondary fuel nozzle disposed in proximity to the closed end of said first wall means for admitting fuel in the combustion zone forwardly and radially of the openings in said baffle when said power plant is operating at low power and said secondary nozzle being disposed forwardly and radially relative to said primary nozzle.

Claim 7

Means for reducing the pollutants emitted from an axial flow gas turbine engine, which engine includes a combustor, a compressor forward of said combustor and a turbine rearward of said combustor, said means comprising: means disposed in said combustor for burning fuel including a first wall means closed at one end defining an annular combustion chamber around the axis of said engine having a combustion zone at the upstream end thereof, said first wall means opened at an opposite end forming an outlet at the downstream end of said chamber for directing combustion products into the turbine; second wall means surrounding a portion of the first wall means and radially spaced therefrom forming an annular premixing passage having an inlet and an outlet and said premixing passage being wholly forward of said passage outlet for receiving air being discharged from the compressor; fuel supply means disposed within said premixing passage for introducing fuel into said premixing passage, the flow of air within said premixing passage atomizing the fuel within the premixing passage, said premixing passage being in gas communication with said combustion zone, baffle means having apertures formed therein disposed across said outlet of said premixing passage for directing the fuel-air mixture from said premixing passage radially across said primary combustion zone toward said other wall of said chamber, said baffle means including a downstream facing surface creating localized eddies within said combustion zone immediately adjacent said downstream facing surface of said baffle means between adjacent openings, and said localized eddies defining stabilization regions for continuous ignition for said combustion zone, at least one secondary fuel nozzle in said premix passage for admitting fuel upstream of said baffle when said power plant is operating at high power, at least one primary fuel nozzle operable independently of said secondary fuel nozzle disposed in proximity to the closed end of said first wall means for admitting fuel in the combustion zone forwardly and radially of the openings in said baffle when said power plant is operating at low power and said secondary nozzle being disposed forwardly and radially relative to said primary nozzle.

Claim 8

Means as defined in claim 5 including an outer casing surrounding and spaced from said first wall means defining therewith an annular passage having an inlet receiving air flow from said compressor, circumferentially spaced holes axially spaced in said first wall means for admitting combustion air and dilution air into said combustion chamber, said circumferentially spaced holes having a predetermined area ratio to the area of said apertures for creating a predetermined pressure field whereby said fuel-air mixture flows substantially in an axial direction from upstream to downstream in said combustion chamber so as to avoid relatively large recirculation zones.

Claim 9

Means as defined in claim 6 wherein said apertures are spaced ahead of said combustor air and dilution air holes with respect to said turbine.

Claim 10

Means as defined in claim 6 wherein said wall means includes an inner and outer wall, said inner wall being closer to said engine axis, said baffle means being disposed adjacent to said inner wall and forming apart thereof to define a substantially front facing portion of said combustion chamber.

Claim 11

Means as defined in claim 8 wherein said baffle means is generally frusto-conical in shape, sloping radially inwardly from an upstream to downstream direction with respect to the flow of said fuel-air mixture.

Claim 12

Means as defined in claim 6 wherein the combined area of said apertures constitutes substantially 30-50% of the entire area of said baffle.

Claim 13

Means as defined in claim 10 wherein the area of said inlet of said premixing passage is less than the combined area of said apertures of said baffle.

Claim 14

Means as defined in claim 9 wherein the base of said frusto-conically shaped baffle is located at its downstream end relative to the flow in said combustion chamber and that the angle at said base and the axis of said engine is substantially 25 degrees.