Optimized advanced RQL combustor for nvPM and NOx
A combustor for rich-quench-lean combustion includes a combustor shell, a combustion chamber delimited by the combustor shell, and fuel injectors. The combustion chamber includes a primary zone, a quench zone, a secondary zone, and an outlet arranged in axial flow series. Openings through the combustor in the quench zone provide a quench air flow into the quench zone. A method for rich-quench-lean combustion for the combustor includes contemporaneously injecting a rich air-fuel mixture into the primary zone and injecting a second air flow into the quench zone in which the second air flow is equal to or less than four times the primary air flow.
1 . A combustor comprising:
a combustor shell;
a combustion chamber delimited by the combustor shell comprising, in axial flow series a primary zone, a quench zone, a secondary zone, and an outlet, wherein the combustor shell includes a plurality of openings disposed within the quench zone that fluidly connects the combustion chamber to a plenum exterior to the combustor shell to define a quench discharge area; and
a plurality of fuel injectors fluidly communicating with the primary zone, wherein the plurality of fuel injectors collectively defines a net fuel discharge area and a net air discharge area;
wherein the net fuel discharge area and the net air discharge area of the injectors are configured to provide a fuel-rich mixture within the primary zone for an operational range of the combustor, and
wherein the quench discharge area and the net air discharge area are configured to provide equal to or less than 4.0 times more quench air flow than a primary air flow within the operational range of the combustor, and
wherein a cross-sectional area of the combustion chamber decreases from the primary zone towards the quench zone, and
wherein the primary zone is greater than or equal to eight percent and less than or equal to fifteen percent of a total volume enclosed by the combustor shell.
2 . The combustor of claim 1 , wherein the quench discharge area and the net discharge area are configured to provide quench flow that is at least 2.0 times the primary air flow.
3 . The combustor of claim 2 , wherein the quench discharge area and the net discharge area are configured to provide quench flow that is equal to or less than 2.8 times the primary air flow.
4 . The combustor of claim 3 , wherein the quench discharge area and the net discharge area are configured to provide quench flow that is at least 2.2 times the primary air flow.
5 . The combustor of claim 4 , wherein the quench discharge area and the net discharge area are configured to provide quench flow that is approximately 2.5 times the primary air flow.
6 . A combustor comprising:
a combustor shell;
a combustion chamber delimited by the combustor shell comprising, in axial flow series a primary zone, a quench zone, a secondary zone, and an outlet, wherein the combustor shell includes a plurality of openings disposed within the quench zone that fluidly connects the combustion chamber to a plenum exterior to the combustor shell to define a quench discharge area; and
a plurality of fuel injectors fluidly communicating with the primary zone, wherein the plurality of fuel injectors collectively defines a net fuel discharge area and a net air discharge area;
wherein the net fuel discharge area and the net air discharge area of the injectors are configured to provide a fuel-rich mixture within the primary zone for an operational range of the combustor, and
wherein the quench discharge area and the net air discharge area are configured to provide equal to or less than 3.0 times more quench air flow than a primary air flow and at least 2.0 times the primary air flow within the operational range of the combustor, and
wherein a cross-sectional area of the combustion chamber decreases from the primary zone towards the quench zone, and
wherein the primary zone is greater than or equal to eight percent and less than or equal to fifteen percent of a total volume enclosed by the combustor shell.
7 . The combustor of claim 6 , wherein the quench discharge area and the net discharge area are configured to provide quench flow that is equal to or less than 2.8 times the primary air mass flow.
8 . The combustor of claim 7 , wherein the quench discharge area and the net discharge area are configured to provide quench flow that is at least 2.2 times the primary air mass flow.
9 . The combustor of claim 8 , wherein the quench discharge area and the net discharge area are configured to provide quench flow that is approximately 2.5 times the primary air mass flow.
10 . A method for rich-quench-lean combustion within a combustor comprising, in axial flow series, a primary zone, a quench zone, and a secondary zone, the method comprising:
injecting a first fuel mass flow rate of a hydrocarbon fuel and a first air mass flow rate into the primary zone of the combustor, the first fuel mass flow rate and the first air mass flow rate defining a rich air-fuel ratio;
injecting a second air mass flow rate into the quench zone of the combustor contemporaneously with injecting the first fuel mass flow rate and the first air mass flow rate;
wherein the second air mass flow rate is greater than the first mass air flow rate and equal to or less than 3.0 times the first air mass flow rate, and
wherein a cross-sectional area of the combustion chamber decreases from the primary zone towards the quench zone, and
wherein the primary zone is greater than or equal to eight percent and less than or equal to fifteen percent of a combined volume of the primary zone, the quench zone, and the secondary zone.
11 . The method of claim 10 , wherein the second mass flow rate is at least 2.0 times the first air mass flow rate.
12 . The method of claim 11 , wherein the second mass flow rate is equal to or less than 2.8 times the first air mass flow rate.
13 . The method of claim 12 , wherein the second mass flow rate is at least 2.2 times the first air mass flow rate.
14 . The method of claim 13 , wherein the second mass flow rate is approximately 2.5 times the first air mass flow rate.
15 . The method of claim 10 , wherein the first fuel mass flow rate is injected into the primary zone of the combustor chamber by a fuel nozzle, and wherein the first air mass flow rate is injected into the primary zone through a swirler surrounding the fuel nozzle.
16 . The method of claim 15 , wherein the second air mass flow rate is introduced into the quench zone via a plurality of openings through the combustor shell, and wherein a cross-sectional area of the combustion chamber decreases from the primary zone towards the plurality of openings within the quench zone.
17 . The method of claim 10 , further comprising:
injecting a third air mass flow rate into at least one of the primary zone, the quench zone, and the secondary zone, wherein the total air mass flow rate exiting the combustor is equal to the summation of the first air mass flow rate, the second air mass flow rate, and the third air mass flow rate.