Cooling in staged fuel systems
View Patent ↗A fuel system includes a fuel supply system. A plurality of fuel nozzles are connected in fluid communication with the fuel supply system to supply fuel from a fuel source to be issued for combustion from the fuel nozzles. A cooling system is included, wherein at least one of the fuel nozzles includes a cooling circuit in addition to a fuel circuit for issuing fuel from the fuel supply system for combustion. The cooling circuit includes an inlet and an outlet. The inlet is in fluid communication with the cooling system for circulation of coolant through the cooling circuit and back to the cooling system out the outlet of the cooling circuit for cooling the fuel circuit with the fuel circuit staged off.
1. A fuel system comprising:
a plurality of fuel nozzles connected in fluid communication with a fuel supply system to supply fuel from a fuel source;
the fuel supply system includes a first fuel manifold connected in fluid communication with a first subset of the fuel nozzles to supply fuel from the fuel source;
a cooling system includes a second fuel manifold connected in fluid communication with a second subset of the fuel nozzles to supply fuel from the fuel source;
wherein each one of the plurality of fuel nozzles includes a fuel circuit with a fuel circuit inlet and a cooling circuit having a cooling circuit inlet, and a cooling circuit outlet;
wherein each one of the plurality of fuel nozzles of the second subset of fuel nozzles is arranged in alternating pattern between a pair of fuel nozzles of the first subset of the fuel nozzles;
wherein fuel from the cooling circuit outlet of one of the fuel nozzles of the first subset of the fuel nozzles flowed to the fuel circuit inlet of an adjacent one of the plurality of fuel nozzles of the second subset of fuel nozzles for combustion; and
wherein fuel from the cooling circuit outlet of one of the fuel nozzles of the second subset of the fuel nozzles flowed to the fuel circuit inlet of an adjacent one of the plurality of fuel nozzles of the first subset of fuel nozzles for combustion.
2. A fuel system as recited in claim 1 , wherein each fuel nozzle that includes the cooling circuit includes:
a nozzle body defining a longitudinal axis including an air passage;
wherein the fuel circuit is radially outboard from the air passage with respect to the longitudinal axis, the fuel circuit extending from the fuel circuit inlet to a fuel circuit annular outlet, wherein the fuel circuit is defined between a fuel circuit inner wall and a fuel circuit outer wall, wherein at least a portion of the fuel circuit outer wall is radially outboard from the fuel circuit inner wall with respect to the longitudinal axis; and
wherein the cooling circuit is defined within at least one of the fuel circuit inner wall and the fuel circuit outer wall, wherein the cooling circuit extends from an axial position proximate the fuel circuit inlet to an axial position proximate the fuel circuit annular outlet.
3. A fuel system as recited in claim 1 , wherein a nozzle body includes an outer air passage defined radially outboard of the fuel circuit with respect to a longitudinal axis, and wherein the outer air passage is defined between a fuel circuit outer wall and an outer air passage wall, and wherein the outer air passage is a converging non-swirling outer air passage.