A gas turbine engine includes a combustor having a combustor air inlet, an axial-centrifugal compressor, a shroud, a secondary flow duct, and a valve. The shroud surrounds at least a portion of the axial-centrifugal compressor and has a surge bleed plenum defined therein that is in fluid communication with, and receives compressed air from, the axial compressor outlet. The secondary airflow duct has a duct inlet that is in fluid communication with the surge bleed plenum, and a duct outlet that is in fluid communication with the combustor air inlet. The valve is mounted on the secondary airflow duct and is movable between a closed position, in which the secondary airflow duct does not provide fluid communication between the surge bleed plenum and the combustor air inlet, and an open position, in which the secondary airflow duct provides fluid communication between the surge bleed plenum and the combustor air inlet.

A gas turbine engine includes a combustor having a combustor air inlet, an axial-centrifugal compressor, a shroud, a secondary flow duct, and a valve. The shroud surrounds at least a portion of the axial-centrifugal compressor and has a surge bleed plenum defined therein that is in fluid communication with, and receives compressed air from, the axial compressor outlet. The secondary airflow duct has a duct inlet that is in fluid communication with the surge bleed plenum, and a duct outlet that is in fluid communication with the combustor air inlet. The valve is mounted on the secondary airflow duct and is movable between a closed position, in which the secondary airflow duct does not provide fluid communication between the surge bleed plenum and the combustor air inlet, and an open position, in which the secondary airflow duct provides fluid communication between the surge bleed plenum and the combustor air inlet.

An embodiment of a torch igniter for a combustor of a gas turbine engine comprises a combustion chamber oriented about an axis, a cap defining an axially upstream end of the combustion chamber and oriented about the axis, a tip defining an axially downstream end of the combustion chamber, a structural wall coaxial with and surrounding the igniter wall, an outlet passage defined by the igniter wall within the tip, and a cooling system. The cooling system comprises an air inlet formed within the structural wall, a first flow path disposed between the structural wall and the igniter wall, and an aperture extending through the igniter wall transverse to the flow direction. The aperture directly fluidly connects the first flow path to the combustion chamber.

An embodiment of a torch igniter for a combustor of a gas turbine engine comprises a combustion chamber oriented about an axis, a cap defining an axially upstream end of the combustion chamber and oriented about the axis, a tip defining an axially downstream end of the combustion chamber, a structural wall coaxial with and surrounding the igniter wall, an outlet passage defined by the igniter wall within the tip, and a cooling system. The cooling system comprises an air inlet formed within the structural wall, a first flow path disposed between the structural wall and the igniter wall, and an aperture extending through the igniter wall transverse to the flow direction. The aperture directly fluidly connects the first flow path to the combustion chamber.

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.

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.

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 nozzle is mounted to the torch wall to issue fuel into the combustion chamber. An ignitor is mounted to the torch wall, extending into the combustion chamber to ignite fuel issued from the fuel nozzle. A cooling passage is in thermal communication with the ignitor for cooling the ignitor with fluid passing through the cooling passage.

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 nozzle is mounted to the torch wall to issue fuel into the combustion chamber. An ignitor is mounted to the torch wall, extending into the combustion chamber to ignite fuel issued from the fuel nozzle. A cooling passage is in thermal communication with the ignitor for cooling the ignitor with fluid passing through the cooling passage.

A method of operating and cleaning a torch ignitor for continuous ignition includes issuing a fuel-lean flow through a combustion chamber of a torch ignitor. The method also includes heating interior surfaces of the torch ignitor, wherein the fuel-lean flow reacts with carbon deposits on the interior surfaces to remove the carbon deposits.

A method of operating and cleaning a torch ignitor for continuous ignition includes issuing a fuel-lean flow through a combustion chamber of a torch ignitor. The method also includes heating interior surfaces of the torch ignitor, wherein the fuel-lean flow reacts with carbon deposits on the interior surfaces to remove the carbon deposits.