Cooling for continuous ignition devices
A torch ignitor system includes a torch wall defining a combustion chamber therein with a flame outlet passing out of the torch wall downstream of the combustion chamber. A fuel injector is mounted to the torch wall to issue fuel into the combustion chamber. At least one ignitor is mounted to the torch wall, positioned to ignite fuel issued from the fuel injector. A film cooler is defined through the torch wall and is operative to issue a film of cooling air from outside the torch wall along an interior surface of the combustion chamber for cooling the torch wall.
1. A torch ignitor system comprising:
a torch wall defining a combustion chamber therein with a flame outlet passing out of the torch wall downstream of the combustion chamber;
a fuel injector mounted to the torch wall to issue fuel into the combustion chamber;
at least one ignitor mounted to the torch wall, positioned to ignite fuel issued from the fuel injector; and
a film cooler defined through the torch wall and operative to issue a film of cooling air from outside the torch wall along an interior surface of the combustion chamber for cooling the torch wall, wherein the film cooler includes a circumferential pattern of cooling holes defined through the torch wall, wherein the cooling holes are tangential relative to a longitudinal axis of the torch wall, further comprising a circumferentially extending louver radially inward from the circumferential pattern of cooling holes for impingement of air from the cooling holes on the louver, wherein the louver opens in a downstream direction.
2. The system as recited in claim 1 , wherein the circumferential pattern of cooling holes is a first circumferential pattern of cooling holes and further comprising at least one second circumferential pattern of cooling holes defined through the torch wall, wherein the first and additional sets of circumferential patterns of cooling holes are spaced apart axially relative to the longitudinal axis.
3. The system as recited in claim 1 , wherein the louver is mounted to an inner surface of the torch wall.
4. The system as recited in claim 1 , wherein the louver is integral with a separate segment of the torch wall, wherein the torch wall is an assembly of the separate segments nested together.
5. The system as recited in claim 2 , further comprising an outlet tube in fluid communication with the combustion chamber extending downstream from the flame outlet, wherein at least one of the additional circumferential patterns of cooling holes is located in the outlet tube and includes a circumferentially extending louvre.
6. The system as recited in claim 2 , further comprising at least one set of torch combustion air holes defined through the torch wall, wherein the torch combustion air holes are defined as tangential passages through the torch wall relative to the longitudinal axis, wherein the torch combustion air holes are free of louvers to issue combustion away from the torch wall toward the longitudinal axis.
7. The system as recited in claim 1 , further comprising an engine case, wherein the torch wall is mounted to the engine case.
8. The system as recited in claim 7 , further comprising a combustor within the engine case, wherein the flame outlet is mounted in fluid communication with an interior combustion space of the combustor, wherein the combustor is spaced apart from the combustion chamber of the torch wall.
9. The system as recited in claim 8 , further comprising a compressor discharge diffuser in the engine case upstream of the torch wall and combustor.
10. The system as recited in claim 9 , wherein a mounting flange extends from the torch wall and is mounted to the engine case.
11. The system as recited in claim 7 , wherein the at least one ignitor extends from outside the engine case, through the mounting flange and into the combustion chamber.
12. The system as recited in claim 11 , wherein the fuel injector is mounted on an opposite side of the flange from the combustion chamber.