Non-swirl dry low NOx (DLN) combustor
View Patent ↗An air/fuel pre-mixer for a gas turbine combustor and a method of pre-mixing air and fuel for a combustor are provided. In one embodiment the pre-mixer includes a first annular premix fuel manifold disposed upstream of the combustor and an annular member concentric with the first premix fuel manifold. Together the annular premix fuel manifold and the annular member define a first venturi shaped air/fuel pre-mix volume between them that has a throat. At or upstream from the throat, the first premix fuel manifold has a plurality of pores whereby the fuel is injected from the first premix fuel manifold to mix with air in the first pre-mix volume. In another embodiment, the annular member is an outer wall, whereas in yet another embodiment, the annular member is a second premix fuel manifold.
1. A fuel injector for a gas turbine combustor, comprising:
a first annular premix fuel manifold adapted to be disposed upstream of the combustor; and
an annular member concentric with the first annular premix fuel manifold and defining a first venturi shaped air/fuel pre-mix volume between the first annular premix fuel manifold and the annular member, the first venturi shaped pre-mix volume having a throat, the first annular premix fuel manifold including a plurality of pores associated with the throat;
and wherein fuel is to be injected from the first annular premix fuel manifold for mixing with air in the first venturi shaped pre-mix volume.
2. The injector according to claim 1 , wherein the annular member further comprises an outer wall disposed to enclose the first annular premix fuel manifold and adapted to be coupled to the combustor.
3. The injector according to claim 1 , wherein the annular member further comprises a second annular premix fuel manifold.
4. The injector according to claim 1 , further comprising a sheet extending downstream from the first annular premix fuel manifold; and wherein the first venturi shaped pre-mix volume extends downstream from the first annular premix fuel manifold.
5. The injector according to claim 4 , wherein the injector comprises a premix injector about 2 inches (50.4 mm) long.
6. The injector according to claim 1 , further comprising a pilot injector disposed downstream from the first annular premix fuel manifold.
7. The injector according to claim 6 , wherein the pilot injector comprises one of a fanformer, a splash plate, and an impinging doublet type fuel injector.
8. The injector according to claim 1 , wherein the plurality of pores comprise holes having diameters between about 0.002 and about 0.004 inches (0.508 mm–0.1016 mm).
9. The injector according to claim 1 further comprising the first venturi shaped pre-mix volume extending downstream from the throat and having a width downstream of the throat less than about a quench distance of the fuel.
10. A gas turbine combustor, comprising:
a combustion chamber;
a first annular premix fuel manifold disposed upstream of the combustion chamber; and
an annular member concentric with the first annular premix fuel manifold and defining a first venturi shaped air/fuel pre-mix volume between the first annular premix fuel manifold and the annular member, the first venturi shaped pre-mix volume having a throat, the first annular premix fuel manifold including a plurality of pores approximately upstream of the throat; and wherein fuel is to be injected from the first annular premix fuel manifold for mixing with air in the first venturi shaped pre-mix volume.
11. The combustor according to claim 10 , wherein the annular member further comprises an outer wall of the injector disposed to enclose the first annular premix manifold and adapted to be coupled to the combustor.
12. The combustor according to claim 10 , wherein the annular member further comprises a second annular premix fuel manifold.
13. The combustor according to claim 12 , further comprising a first and a second premix fuel supply in communication with the first and the second premix annular fuel manifolds respectively.
14. The combustor according to claim 10 , further comprising a sheet extending downstream from the first annular premix fuel manifold whereby the first venturi shaped pre-mix volume extends downstream from the first premix fuel manifold.
15. The combustor according to claim 14 , wherein the injector is about 2 inches long (50.4 mm).
16. The combustor according to claim 10 , further comprising a pilot injector disposed downstream from the first annular premix fuel manifold.
17. The combustor according to claim 16 , wherein the pilot injector comprises one of a fanformer, a splash plate, and an impinging doublet type fuel injector.
18. The combustor according to claim 10 , wherein the plurality of pores comprise holes having diameters between about 0.002 and about 0.004 inches (0.0508 mm–0.1016 mm).
19. The combustor according to claim 10 , further comprising the first venturi shaped pre-mix volume extending downstream from the throat and having a width downstream of the throat less than about a quench distance of the fuel.
20. A method of pre-mixing air and fuel for a gas turbine combustor, comprising:
defining a first venturi shaped pre-mix volume between a first annular premix fuel manifold and an annular member, the first venturi shaped pre-mix volume having a throat; and injecting fuel from the first annular premix fuel manifold through a plurality of pores in the first annular premix fuel manifold approximately upstream of the throat; and
mixing the fuel with air in the first venturi shaped pre-mix volume.
21. The method according to claim 20 , further comprising using the annular member as an outer wall to enclose the first annular premix fuel manifold.
22. The method according to claim 20 , using the annular member further as a second annular premix fuel manifold.
23. The method according to claim 22 , further comprising placing a first and a second premix fuel supply in communication with the first and the second annular premix fuel manifolds respectively.
24. The method according to claim 20 , further comprising extending a sheet downstream from the first annular premix fuel manifold and less than about a quench distance of the fuel from the annular member thereby extending the first venturi shaped pre-mix volume downstream from the first annular premix fuel manifold.
25. The method according to claim 24 , wherein the injector is about 2 inches (50.4 mm) long.
26. The method according to claim 20 , further comprising disposing a pilot injector downstream from the first annular premix fuel manifold.
27. The method according to claim 26 , wherein the pilot injector comprising one of a fanformer, a splash plate, or an impinging doublet type fuel injector.
28. The method according to claim 20 , wherein the plurality of pores comprise holes having diameters between about 0.002 and about 0.004 inches (0.0508 mm–0.1016 mm).