Fuel injector for high flame speed fuel combustion
View Patent ↗A multiple fuel capable, pre-mixed, low emission injector is provided which is particularly suited for burning high flame speed fuels. The fuel injector includes an injector body having a preliminary pre-mixing chamber, an intermediate pre-mixing chamber and a final pre-mixing chamber. A fuel distributor separates the preliminary pre-mixing chamber from the intermediate pre-mixing chamber. A guide vane separates the intermediate pre-mixing chamber from the final pre-mixing chamber.
1. A fuel injector apparatus, comprising:
an elongated tubular injector body having an inlet end and an outlet end, the body having an inner wall defining an interior, the inner wall having one or more near-wall layer air injection ports defined therein;
a guide vane separating a final mixing chamber adjacent the outlet end from one or more pre-mixing chambers upstream of the guide vane, the guide vane including:
a non-perforated lateral vane portion attached to the inner wall upstream of the one or more near-wall layer air injection ports and extending laterally inward; and
an axial vane portion extending downstream from the lateral vane portion and defining an axially central flow passage for all fuel-air mixture from the one or more pre-mixing chambers, the axial vane portion and the inner wall defining an injection annulus downstream of the lateral vane portion, the one or more near-wall layer air injection ports opening into the injection annulus; and
a fuel distributor disposed in the interior upstream of the guide vane, the fuel distributor including a lateral distributor portion attached to the inner wall and extending laterally inward, an axially projecting distributor portion projecting downstream from the lateral distributor portion, and a distributor end wall having a plurality of distribution openings, such that fuel and air mixture exits the distributor end wall through the distribution openings in an axially central core flow stream aligned with the axially central flow passage of the guide vane, the distributor end wall being tapered in the downstream direction to a central tip.
2. The apparatus of claim 1 , wherein:
the guide vane is configured such that fuel and air mixture exits the outlet end in an axially central core flow stream surrounded by an annular near-wall layer flow stream relatively free of fuel so that near-wall layer flashback is inhibited.
3. The apparatus of claim 2 , wherein the guide vane is configured such that the axially central core flow stream has a sufficiently high core flow velocity such that a core flashback mechanism is prevented from occurring.
4. The apparatus of claim 1 , wherein:
the inner wall of the injector body has one or more intermediate mix air injection ports defined therein between the fuel distributor and the guide vane, for providing additional mix air to the fuel and air mixture exiting the distributor end wall, and for establishing an initial near-wall layer air flow along an inside wall of the axial vane portion of the guide vane.
5. The apparatus of claim 1 , wherein:
the one or more pre-mixing chambers include a preliminary pre-mixing chamber between the inlet end and the fuel distributor, and an intermediate pre-mixing chamber between the fuel distributor and the guide vane.
6. The apparatus of claim 1 , wherein:
the one or more pre-mixing chambers includes a primary pre-mixing chamber adjacent the inlet end of the injector body; and
the inner wall has one or more primary air injection ports defined therein and communicated with the primary pre-mixing chamber.
7. The apparatus of claim 6 , further comprising:
one or more gaseous fuel inlets communicated with the primary pre-mixing chamber.
8. The apparatus of claim 6 , further comprising:
one or more liquid fuel nozzles communicated with the primary pre-mixing chamber.
9. The apparatus of claim 6 , further comprising:
one or more gaseous fuel inlets communicated with the primary pre-mixing chamber; and
one or more liquid fuel nozzles communicated with the primary pre-mixing chamber, such that the apparatus has the capability to operate on gaseous and liquid fuels simultaneously.
10. The apparatus of claim 1 , wherein:
the axial vane portion terminates in a sharp edged guide vane outlet configured to atomize any remaining liquid fuel droplets.
11. The apparatus of claim 1 , wherein:
the outlet end of the injector body converges to a reduced diameter outlet opening.
12. The apparatus of claim 1 , wherein:
the outlet end of the injector body has a venturi shape.
13. The apparatus of claim 1 , wherein:
the outlet end of the injector body diverges to an enlarged diameter outlet opening.
14. The apparatus of claim 1 , further comprising:
an annular outer wall concentrically disposed about the injector body and defining an annular air supply passage between the outer wall and the injector body, the one or more near-wall layer injection ports being communicated with the annular air supply passage.
15. The apparatus of claim 1 , wherein:
the inner wall of the injector body has one or more intermediate mix air injection ports defined therein between the fuel distributor and the guide vane, for providing additional mix air to the fuel and air mixture exiting the tapered distributor end wall, at least some of the intermediate mix air injection ports being laterally aligned with the distribution openings in the tapered distributor end wall so as to aid in mixing the fuel and air mixture exiting the tapered distributor end wall.