Patent ID: 10738703

Abstract:
A gas turbine engine includes a plurality of rotating components housed within a main compressor section and a turbine section. A first tap is connected to the main compressor section and configured to deliver air at a first pressure. A heat exchanger is connected downstream of the first tap. A cooling air valve is configured to selectively block flow of cooling air across the heat exchanger. A cooling compressor is connected downstream of the heat exchanger. A shut off valve stops flow between the heat exchanger and the cooling compressor. A second tap is configured to deliver air at a second pressure which is higher than the first pressure. A mixing chamber is connected downstream of the cooling compressor and the second tap. The mixing chamber is configured to deliver air to at least one of the plurality of rotating components. A system stops flow between the cooling compressor and the plurality of rotating components. A controller is configured to modulate flow between the heat exchanger and the plurality of rotating components under certain power conditions of the gas turbine engine. The controller is programmed to control the cooling air valve, the shut off valve and the system such that flow is stopped between the heat exchanger and the cooling compressor only after the cooling compressor has been stopped.