Gas turbine engine buffer air augmentation system and method

A method of providing buffer air to an engine compartment of a gas turbine engine, wherein the gas turbine engine includes a compressor section and a turbine section, wherein the turbine section is engaged with the compressor section by a shaft, and the shaft is supported by a bearing disposed within a bearing compartment, the method comprising:

• providing a flow of compressor bleed air to an engine compartment, the compressor bleed air provided from the compressor section;
• providing a flow of compressed air from a compressed air source to an air turbine starter (ATS), wherein the flow of compressed air drives the air turbine starter and the driven air turbine starter drives the compressor section and the turbine section during a start-up segment of an engine operational cycle of the gas turbine engine, wherein the flow of compressed air exits the air turbine starter as a flow of ATS exhaust gas through an exhaust port of the air turbine starter;
• and
• controlling the flow of ATS exhaust gas into the engine compartment during the start-up segment of an engine operational cycle of the gas turbine engine using a fluid flow control device in communication with a controller, the controller configured to control the flow of ATS exhaust gas between the exhaust port of the air turbine starter and the engine compartment through the fluid control device until air from the compressor bleed source is at or above a predetermined air pressure value.

A buffer air augmentation system for a gas turbine engine, the gas turbine engine having a compressor section and a turbine section engaged with one another by at least one shaft, a plurality of bearings supporting the shaft, and an engine compartment, the system comprising:

• an air turbine starter (ATS) disposed to drive the compressor section and a turbine section, the air turbine starter configured to receive a flow of compressed air from a compressed air source, and the air turbine starter having an exhaust port through which a flow of ATS exhaust gas exits the air turbine starter;
• and
• flow ducting configured to selectively provide fluid communication between the exhaust port of the air turbine starter and the engine compartment, the flow ducting including a fluid flow control device configured to control the flow of ATS exhaust gas between the exhaust port of the air turbine starter and the engine compartment;
• wherein the buffer air augmentation system is in communication with a controller, and the controller is in communication with the fluid flow control device and a non-transitory memory storing instructions, which instructions when executed cause the controller to control the fluid flow control device to control the flow of ATS exhaust gas between the exhaust port of the air turbine starter and the engine compartment until air within the engine compartment is at or above a predetermined air pressure value.