Combustor for a gas turbine
A combustor for a gas turbine, having a pre-combustion chamber having a peripheral wall around a center axis of the pre-combustion chamber, the peripheral wall has an inner panel and an outer panel and a passage provided between the inner and the outer panels, a swirler which is connected to the pre-combustion chamber for providing pre-combustion chamber with a flow of an oxidant gas, at least a pilot fuel injector, wherein the swirler is connected to the peripheral wall in such a way that a portion of the oxidant gas from the swirler is channeled to the passage, and the pilot fuel injector is connected to the passage for injecting a flow of pilot fuel into the passage.
1. A combustor for a gas turbine, comprising:
generally arranged about a centre axis and in axial sequence a swirler arrangement, a pre-chamber and a combustion chamber, wherein in use an oxidant gas flows into the combustor in a general direction from the swirler arrangement towards the combustion chamber,
wherein the swirler arrangement comprises a swirler and a main fuel injector, the swirler having an inlet and an outlet, and wherein in use a first portion of the oxidant gas flows through the outlet of the swirler mixing with a main fuel flow from the main fuel injector and passes into and through the pre-chamber to combust in the combustion chamber,
wherein the pre-chamber comprises a generally annular peripheral wall, the peripheral wall comprising an inner panel and an outer panel forming a passage therebetween, the passage comprises an inlet and an outlet, and
a pilot fuel injector located between the inner panel and the outer panel for injecting a flow of pilot fuel into the combustion chamber,
wherein a second portion of the oxidant gas is channelled through the passage and mixes with a pilot fuel flow from the pilot fuel injector,
wherein the inlet of the passage is located between the inlet and the outlet of the swirler, and
wherein the oxidant gas flow enters the inlet of the swirler where the second portion flows into the inlet of the passage and the first portion flows through the outlet of the swirler.
2. The combustor according to claim 1 ,
wherein the outlet of the passage is at a downstream end of the pre-chamber.
3. The combustor according to claim 1 ,
wherein the pre-chamber has an axial length L, and
wherein the pilot fuel injector has a nozzle, the nozzle is located within 50% of L.
4. The combustor according to claim 1 ,
wherein the pilot fuel and/or mixture of pilot fuel and the second portion of oxidant gas is injected directly into the combustion chamber.
5. The combustor according to claim 1 , wherein the pilot fuel and/or mixture of pilot fuel and the second portion of oxidant gas is injected at angle of up to 45° from the centre axis.
6. The combustor according to claim 1 , wherein the pilot fuel and/or mixture of pilot fuel and the second portion of oxidant gas is injected at tangential angle of up to 45° into the combustion chamber.
7. The combustor according to claim 1 ,
wherein the main fuel injector has a nozzle located radially outward of the swirler or radially between the inlet and the outlet of the swirler.
8. The combustor according to claim 1 ,
wherein the pre-chamber having a shape defined by the peripheral wall being parallel, divergent, convergent or any combination of parallel, divergent or convergent.
9. The combustor according to claim 1 , wherein the combustor comprises a plurality of pilot fuel injectors including the pilot fuel injector.
10. The combustor according to claim 9 , wherein the plurality of pilot fuel injectors is connected to a respective manifold of a plurality of manifolds, the plurality of manifolds being connected to a common annular passage connecting the plurality of manifolds with a source of pilot fuel, the common annular passage being concentric with the centre axis.
11. The combustor according to claim 9 ,
wherein a number of pilot fuel injectors of the plurality of pilot fuel injectors is between 9 and 12.
12. The combustor according to claim 1 ,
wherein the second portion of oxidant gas in the passage is between 10% to 50% of the oxidant gas flow.
13. The combustor according to claim 1 , further comprising: a pilot burner upstream of the pre-chamber which comprises a pilot burner surface separating the pilot burner from the pre-chamber, wherein the pilot burner comprises a liquid pilot fuel injector which is arranged to the pilot burner surface for injecting liquid pilot fuel into the pre-chamber.
14. The combustor according to claim 1 ,
wherein the pre-chamber has an axial length L, and
wherein the pilot fuel injector has a nozzle, the nozzle is located within 10% of L.
15. The combustor according to claim 1 ,
wherein the pre-chamber comprises an axial length L, and
wherein the pilot fuel injector comprises a nozzle, the nozzle is located at a downstream end of the pre-chamber.
16. The combustor according to claim 1 ,
wherein the pilot fuel and/or mixture of pilot fuel and the second portion of oxidant gas is injected in an axial direction into the combustion chamber.
17. The combustor according to claim 1 , wherein the combustor comprises a plurality of pilot fuel injectors including the pilot fuel injector, wherein the plurality of pilot fuel injectors are regularly distributed around the centre axis.