A gas turbine engine comprises a main compressor section having a high pressure compressor with a downstream most end, and more upstream locations. A turbine section has a high pressure turbine. A first tap taps air from at least one of the more upstream locations in the main compressor section, passing the tapped air through a first heat exchanger and then to a cooling compressor. A second tap taps air from a location closer to the downstream most end than the location of the first tap, and the first and second taps mix together and are delivered into the high pressure turbine. The cooling compressor is positioned downstream of the first heat exchanger, and upstream of a location where air from the first and second taps mix together.

By using a combustion flue gas (18) from a power turbine (16), a high-pressure secondary compressed air (12C) is subjected to heat exchange in a first heat exchange unit (19A) of an exhaust heat recovery device (19), and by using resultant heat-exchanged flue gas (18A), a low-pressure primary compressed air (12A) is subjected to heat recovery in a second heat exchange unit (19B) of a saturator (31). Then, a primary compressed air (12B) that has been subjected to heat recovery in the second heat exchange unit (19B) is introduced into a secondary air compressor (22) to increase the pressure of the air, and then the high-pressure air is subjected to heat recovery in the first heat exchange unit (19A), producing a secondary compressed air (12D). The secondary compressed air (12D) is introduced into a combustor (14) and combusted using fuel.

A gas turbine engine comprises a main compressor section having a high pressure compressor with a downstream discharge, and more upstream locations. A turbine section has a high pressure turbine. A tap taps air from at least one of the more upstream locations 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. An intercooling system for a gas turbine engine is also disclosed.

A gas turbine engine includes a plurality of rotatable components housed within a compressor section and a turbine section. A tap is connected to a location upstream of a downstream most location in the compressor section. The tap is connected to a heat exchanger. Downstream of the heat exchanger is a shut off valve and downstream of the shut off valve is a cooling compressor. The cooling compressor is connected to deliver cooling air through a chamber, and then to at least one of the plurality of rotatable components. The chamber is provided with at least one check valve configured to selectively allow flow directly from a more downstream location in the compressor section than the location upstream. The flow from the more downstream location has a higher pressure than a flow from the location upstream. There is a system for stopping operation of the cooling compressor. There is a control for closing the shut off valve. The cooling compressor is configured to compress air to a greater pressure than the higher pressure, such that when the cooling compressor is providing air, the at least one check valve is configured to maintain a closed position, but when said cooling compressor is not providing compressed air, the at least one check valve is configured to allow said higher pressure flow into said chamber. A method is also disclosed.

A method of modulating cooling of gas turbine engine components includes the steps of identifying an input indicative of a usage rate for at least a first gas turbine engine component of a plurality of gas turbine engine components. A cooling system is operated for at least the first gas turbine engine component. The cooling system is moved between a higher cooling potential mode and a lower cooling potential mode based on the identified rate. A gas turbine engine is also disclosed.

A turbofan engine assembly including an internal combustion engine in fluid communication between a compressor and a turbine, the internal combustion engine having an engine shaft, a bypass duct surrounding the internal combustion engine, and a fan drivingly engaged to the engine shaft via a gearbox, the gearbox configured to increase an output speed of the fan relative to an input speed of the engine shaft.

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.

A turbine temperature estimation system controls a valve in a cooling passage to control the flow rate of cooling air supplied to a turbine component on the basis of its temperature. The system includes a coating layer formed on a surface of a component of the gas turbine; a measuring unit to supply an electric current to the coating layer and to measure a change in a resistance value of the coating layer; and a controller to estimate a temperature of the coating layer on the basis of the resistance value. The coating layer includes a heat shielding material and a resistive material whose resistance value changes with temperature. A cooling passage supplies cooling air to cool the turbine component, and the controller controls an opening of the cooling passage according to a voltage value of the coating layer.

Systems and methods for generating electricity in an efficient manner using a recovery gas flow are provided. The electric generation system may comprise recovery turbine coupled to an electric generation assembly, wherein a rotor assembly is rotatably coupled to a rotating stator assembly for generating electricity. The electric generation assembly may include a heat recovery generator, wherein the heat from the generation of electricity is transferred to a flow of gas to produce a recovery gas flow. During operation, this recovery gas flow can be used as a prime mover to rotate the rotor and conserve energy. Particularly, the system may include a compressor coupled to receive and compress the recovery gas flow, such that the recovery gas flow may supply energy to the recovery turbine. Further, an expansion cooler may cool the recovery gas flow to providing the initial gas flow that circulates through out the system.

A propulsion system for an aircraft includes a gas generating core engine generates an exhaust gas flow that is expanded through a turbine section, a power turbine driven by the exhaust gas flow, a propulsor coupled to the power turbine, a hydrogen fuel system configured to supply hydrogen fuel to the combustor through a fuel flow path, a condenser arranged along the core flow path and configured to extract water from the exhaust gas flow, and an evaporator arranged along the core flow path receiving a portion of the water extracted by the condenser to generate a steam flow that is injected into the core flow path upstream of the turbine section.