Patent attributes
A gas turbine engine comprises a main compressor section having a high pressure compressor, and at least one more upstream compressor. A turbine section has a high pressure turbine. A tap line taps air from at least one of the more upstream compressors in the compressor section, passes the tapped air through a heat exchanger and then to a cooling compressor. The cooling compressor compresses air downstream of the heat exchanger, and delivers air into the high pressure turbine. A bypass valve is positioned downstream of the main compressor section, and upstream of the heat exchanger. The bypass valve selectively delivers air directly to the cooling compressor without passing through the heat exchanger under certain conditions. An intercooling system is also disclosed.