Ducted firewall with upper bifi bleed for modulated core ventilation

A method of cooling one or more external components of a gas turbine engine, the gas turbine engine including a fan section, a compressor section, a combustor section, a turbine section, and an outer casing disposed radially outside of the compressor section, combustor section, and the turbine section, wherein the gas turbine engine has a core gas path that extends through the compressor section, the combustor section, and the turbine section, the core gas path disposed radially inside of the outer casing, a fan bypass air duct defined by an inner radial flow path boundary and an outer radial flow path boundary, a member extending between the inner radial flow path boundary and the outer radial flow path boundary, the member including an air inlet configured to receive a flow of fan bypass air from the fan bypass air duct, and an outside core annular region radially disposed between the outer casing and the inner radial boundary flow path boundary, an aft fan annular compartment disposed forward of the outside core annular region and defined by the outer casing, an annular aft inner diameter panel, and a firewall, wherein the one or more external components are disposed in the outside core annular region, the method comprising:

• using a valve to selectively control passage of a flow of fan bypass air from the air inlet disposed within the member to a manifold disposed within the aft fan annular compartment, and thereafter into to the outside core annular region, wherein the valve is controllable to move from a first configuration to a second configuration, and controllable to move from the second configuration to the first configuration, wherein in the second configuration, the flow of fan bypass air into the outside core annular region is volumetrically greater than the flow of fan bypass air into the outside core annular region in the first configuration.

A gas turbine engine, comprising:

• a fan section;
• a compressor section;
• a combustor section;
• a turbine section;
• an outer casing disposed radially outside of the compressor section, combustor section, and the turbine section;
• wherein the engine has a core gas path that extends through the compressor section, the combustor section, and the turbine section, the core gas path disposed radially inside of the outer casing, a fan bypass air duct defined by an inner radial flow path boundary and an outer radial flow path boundary, and a member extending between the inner radial flow path boundary and the outer radial flow path boundary;
• an outside core annular region radially disposed between the outer casing and the inner radial boundary flow path boundary;
• an aft fan annular compartment disposed forward of the outside core annular region, wherein the aft fan annular compartment is defined by the outer casing, an annular aft inner diameter panel, and a firewall;
• a fan air circulation system that includes an air inlet disposed within the member,-and-a manifold disposed within the aft fan annular compartment, and a valve, wherein the fan circulation system defines a fan bypass air flow passage that extends from the air inlet, through the manifold, and into the outside core annular region;
• and
• a system controller in communication with the valve and a non-transitory memory storing instructions, which instructions when executed cause the system controller to:
• selectively control passage of the flow of fan bypass air into the outside core annular region using the valve, the selective control including passing a first said flow of fan bypass air into the outside core annular region during a first engine operating condition, and passing a second said flow of fan bypass air into the outside core annular region during a second engine operating condition, wherein the first said flow of fan bypass air is volumetrically greater than the second said flow of fan bypass air.