Flexure seal for fuel injection nozzle

1. A fuel injector for a gas turbine engine comprising:

a) an injector body having a feed arm with a nozzle body connected thereto;

b) a fuel conduit fluidly connecting a fuel inlet portion of the feed arm to a fuel circuit in the nozzle body to form a fuel path through the injector body;

c) an outer feed arm wall outboard of the fuel conduit;

d) a prefilmer within the nozzle body operatively connected to the fuel conduit of the feed arm to define a portion of the fuel circuit in the nozzle body, wherein the fuel conduit of the feed arm and the prefilmer of the nozzle body form portions of an interior wall of the injector body;

e) an outer nozzle body wall outboard of the prefilmer, wherein the outer nozzle body wall and outer feed arm wall form portions of an exterior wall of the injector body;

f) a main insulative gap defined between the interior and exterior walls of the injector body to thermally insulate the fuel path of the injector body from ambient conditions;

g) a fuel swirler wall disposed radially inward of the prefilmer, with a prefilmer chamber defined therebetween;

h) an inner air swirler disposed radially inward of a portion of the fuel swirler wall;

i) an inner insulative gap defined between the fuel swirler and the inner air swirler, the inner insulative gap being in fluid communication with the main insulative gap; and

j) a flexure seal for isolating the main insulative gap from ambient fluid entering into the main insulative gap therethrough and providing relative axial and radial movement between the interior and exterior walls of the injector body, the flexure seal forming part of the exterior wall of the injector body joining the outer feed arm wall to the outer nozzle body wall, wherein the flexure seal has a cross-section with a generally sigmoid portion that is mounted to the prefilmer.

2. A fuel injector as recited in claim 1 , further comprising an annular flexure beam disposed in a gap between the fuel swirler wall and the inner air swirler, the annular flexure beam being joined at a first end to the fuel swirler wall and being joined at a second end to the inner air swirler.

3. A fuel injector as recited in claim 1 , further comprising sealing means disposed between the fuel swirler wall and the inner air swirler and is selected from the group consisting of a c-seal, d-ring, e-ring, and o-ring.

4. A fuel injector as recited in claim 1 , further comprising a bellows structure disposed across the main insulative gap.

5. A fuel injector as recited in claim 4 , wherein the bellows structure is disposed between the fuel conduit and a portion of the exterior wall surrounding the fuel conduit.

6. A fuel injector as recited in claim 1 , wherein the inner air swirler includes an upstream portion and a downstream portion joined together, the downstream portion being joined to the fuel swirler wall, and wherein an upstream seal section of the downstream portion of the inner air swirler forms an annular flexure beam disposed between the upstream portion of the inner air swirler and the fuel swirler wall.

7. A fuel injector as recited in claim 1 , wherein at least a portion of the main insulative gap contains a noble gas.

8. A nozzle comprising:

a) an inlet at an upstream end of the nozzle;

b) a discharge outlet at a downstream end of the nozzle;

c) a fluid delivery passage extending between the inlet and the discharge outlet;

d) an interior annular wall bounding one side of the fluid delivery passage along a length thereof, wherein the internal annular wall is in heat transfer relation with fluid passing through the fuel delivery passage;

e) an exterior annular wall interposed between the interior annular wall and ambient conditions, wherein the exterior and interior walls have downstream tip ends that are adapted for relative longitudinal movement at an interface;

f) an internal insulating gap interposed between the interior and exterior walls to insulate the internal wall from ambient temperature conditions exterior to the nozzle; and

g) a generally sigmoid shaped flexure seal internal to the nozzle for isolating a portion of the insulating gap from ambient fluid entering into the portion of the gap through the interface and for allowing axial and radial movement between the interior and exterior annular walls, wherein the flexure seal is disposed across the portion of the insulating gap with an upstream end of the flexure seal mounted to the interior annular wall, with a downstream end of the flexure seal mounted to the exterior annular wall outboard of the interior annular wall, wherein the upstream end of the flexure seal is wider than the downstream end thereof, and wherein the flexure seal is contained entirely within the insulating gap.

9. A nozzle as recited in claim 8 , further comprising a fuel swirler wall disposed radially inward of a prefilmer portion of the interior annular wall, with a prefilmer chamber defined therebetween, an inner air swirler disposed radially inward of a portion of the fuel swirler wall, and an annular flexure beam disposed in a gap between the fuel swirler wall and the inner air swirler, the annular flexure beam being joined at a first end to the fuel swirler wall and being joined at a second end to the inner air swirler.

10. A nozzle as recited in claim 9 , wherein at least a portion of the insulating gap contains a noble gas.

11. A nozzle as recited in claim 8 , further comprising a fuel swirler wall disposed radially inward of a prefilmer portion of the interior annular wall, with a prefilmer chamber defined therebetween, an inner air swirler disposed radially inward of a portion of the fuel swirler wall, and a c-seal disposed between the fuel swirler wall and the inner air swirler.

12. A nozzle as recited in claim 8 , further comprising a fuel swirler wall disposed radially inward of a prefilmer portion of the interior annular wall, with a prefilmer chamber defined therebetween, an inner air swirler disposed radially inward of a portion of the fuel swirler wall, and a bellows structure disposed across the internal insulating gap.

13. A nozzle as recited in claim 8 , further comprising an inner air swirler radially inward of a fuel swirler that is radially inward of the interior annular wall, wherein the inner air swirler includes an upstream portion and a downstream portion joined together, the downstream portion being joined to the fuel swirler wall.

14. A nozzle as recited in claim 13 , wherein an upstream seal section of the downstream portion of the inner air swirler forms an annular flexure beam disposed between the upstream portion of the inner air swirler and the fuel swirler wall.

15. A fuel injector for a gas turbine engine comprising:

a) an injector body having a feed arm with a nozzle body connected thereto;

b) a fuel conduit fluidly connecting a fuel inlet portion of the feed arm to a fuel circuit in the nozzle body to form a fuel path through the injector body;

c) an outer feed arm wall outboard of the fuel conduit;

d) a prefilmer within the nozzle body operatively connected to the fuel conduit of the feed arm to define a portion of the fuel circuit in the nozzle body, wherein the fuel conduit of the feed arm and the prefilmer of the nozzle body form portions of an interior wall of the injector body;

e) an outer nozzle body wall outboard of the prefilmer, wherein the outer nozzle body wall and outer feed arm wall form portions of an exterior wall of the injector body;

f) a main insulative gap defined between the interior and exterior walls of the injector body to thermally insulate the fuel path of the injector body from ambient conditions;

h) a fuel swirler disposed radially inward of the prefilmer with a prefilming chamber defined between the fuel swirler and the prefilmer;

i) an inner air swirler disposed radially inward of the fuel swirler with an inner insulative gap defined between the inner air swirler and the fuel swirler, wherein the inner insulative gap is in fluid communication with the main insulative gap of the injector body; and

j) an annular flexure beam disposed in the inner insulative gap between the fuel swirler and the inner air swirler, wherein the annular flexure beam is mounted at a first end thereof to an upstream end of the fuel swirler, and wherein the flexure beam is mounted at a second end thereof to the inner air swirler.

16. A fuel injector as recited in claim 15 , wherein a portion of the main insulative gap within the feed arm is vented to engine compressor discharge air.