Abstract: A system is provided for an aircraft. This aircraft system includes an aircraft powerplant, a powerplant sensor system, an environment sensor system and a monitoring system. The aircraft powerplant includes a heat engine. The powerplant sensor system is configured to provide engine data indicative of one or more operating parameters of the heat engine. The environment sensor system is configured to provide environment data indicative of one or more environmental parameters of an environment in which the heat engine is operating. The monitoring system is configured to determine formation of a contrail and quantify an impact of the contrail when formed based on the engine data and the environment data.

Abstract: An aircraft propulsion system includes a gas turbine engine, a hydrogen-exhaust heat exchanger, and a hydrogen turboexpander. The hydrogen-exhaust heat exchanger is disposed relative to a turbine exhaust section so that a flow of exhaust gas exiting the engine is in communication with the hydrogen-exhaust heat exchanger. The hydrogen-exhaust heat exchanger changes a flow of liquid hydrogen to gaseous hydrogen. The hydrogen turboexpander has parallel first and second rotor shafts within a housing that includes a first and second rotor shaft cavities. The first rotor shaft and the first rotor shaft cavity define a first rotor shaft fluid flow path (RSFFP). The second rotor shaft and the second rotor shaft cavity define a second RSFFP. The first RSFFP is in series with the second RSFFP between an inlet port and an exit port. The exit port is in fluid communication with the combustor.

Abstract: An engine system includes an engine core assembly, a fuel system and a cooling circuit. The engine core assembly includes a core flowpath, a compressor section, a combustor section and a turbine section. The combustor section includes a combustor adjacent a plenum. The fuel system includes a fuel flowpath, a fuel reservoir, a fuel-cooling air heat exchanger and a fuel injector. The fuel flowpath is configured to direct hydrogen fuel, received from the fuel reservoir, through the fuel-cooling air heat exchanger to the fuel injector. The fuel injector is configured to introduce the hydrogen fuel into the combustor. The cooling circuit is configured to direct cooling air, bled from the plenum, through the fuel-cooling air heat exchanger to the turbine section. The fuel-cooling air heat exchanger is configured to exchange heat energy between the hydrogen fuel flowing within the fuel flowpath and the cooling air flowing within the cooling circuit.

Abstract: An aircraft propulsion system is provided that includes a turbine engine and an intercooler (IC). The turbine engine includes a source of non-hydrocarbon fuel, and a low pressure compressor having an LPC air inlet and outlet, and a high pressure compressor having an HPC air inlet and outlet. The intercooler has an IC air inlet, an IC air outlet, a U-shaped air passage, and crossflow tubes. The IC air inlet is in fluid communication with the LPC air outlet. The IC air outlet is in fluid communication with the HPC air inlet. The U-shaped air passage is in fluid communication with the IC air inlet and outlet. The crossflow tubes extend through the U-shaped air passage. The crossflow tubes are in fluid communication with the source of non-hydrocarbon fuel, and are configured to contain a flow of the non-hydrocarbon fuel therethrough.

Abstract: A computer system includes a processor controls the computer system to perform a computer-implemented method of determining a minimum humidity required for formation and persistence of contrails produced by an engine of an aircraft. The computer-implemented method includes determining engine performance model parameters of the engine at desired operating conditions with zero humidity; determining additional energy flow out of the engine; and determining an exhaust plume temperature scaling factor. The method further comprises determining a contrail engine efficiency parameter (noverall_?) based on additional energy flow out of the engine and the exhaust plume temperature scaling factor; and generating an improved Schmidt-Appleman equation based on the contrail engine efficiency parameter (noverall_?).

Abstract: An aircraft propulsion system is provided that includes a turbine engine and an intercooler (IC). The turbine engine includes a source of non-hydrocarbon fuel, and a low pressure compressor having an LPC air inlet and outlet, and a high pressure compressor having an HPC air inlet and outlet. The intercooler has an IC air inlet, an IC air outlet, a U-shaped air passage, and crossflow tubes. The IC air inlet is in fluid communication with the LPC air outlet. The IC air outlet is in fluid communication with the HPC air inlet. The U-shaped air passage is in fluid communication with the IC air inlet and outlet. The crossflow tubes extend through the U-shaped air passage. The crossflow tubes are in fluid communication with the source of non-hydrocarbon fuel, and are configured to contain a flow of the non-hydrocarbon fuel therethrough.

Abstract: An engine system includes an engine core assembly, a fuel system and a cooling circuit. The engine core assembly includes a core flowpath, a compressor section, a combustor section and a turbine section. The combustor section includes a combustor adjacent a plenum. The fuel system includes a fuel flowpath, a fuel reservoir, a fuel-cooling air heat exchanger and a fuel injector. The fuel flowpath is configured to direct hydrogen fuel, received from the fuel reservoir, through the fuel-cooling air heat exchanger to the fuel injector. The fuel injector is configured to introduce the hydrogen fuel into the combustor. The cooling circuit is configured to direct cooling air, bled from the plenum, through the fuel-cooling air heat exchanger to the turbine section. The fuel-cooling air heat exchanger is configured to exchange heat energy between the hydrogen fuel flowing within the fuel flowpath and the cooling air flowing within the cooling circuit.

Abstract: An engine system is provided that includes an open propulsor rotor, an engine core assembly, a bypass flowpath and a condenser. The engine core assembly is configured to drive rotation of the open propulsor rotor. The engine core assembly includes a core flowpath, a compressor section, a combustor section and a turbine section. The core flowpath extends through the compressor section, the combustor section and the turbine section from an inlet into the core flowpath to an exhaust from the core flowpath. The bypass flowpath bypasses the engine core assembly. The condenser is configured to exchange heat energy between combustion products flowing within the core flowpath downstream of the combustor section and bypass air flowing within the bypass flowpath.

Abstract: An aircraft propulsion system and method is provided. The system includes compressor, combustor, and turbine sections, a fuel source, a heat exchanger, a compressor bleed air passage, and a cooling air passage. The fuel source is configured to contain a non-hydrocarbon fuel. The heat exchanger has separate air and fuel passages. The air passage permits passage of the compressed air therethrough. The fuel passage is configured to permit a passage of the non-hydrocarbon fuel therethrough. The compressor bleed air passage is configured to receive compressed air bleed off a core flow path upstream of the combustor section. The compressor bleed air passage is in fluid communication with the air passage air inlet. The cooling air passage is configured to receive compressed air exiting the air passage air outlet and configured to direct the compressed bleed air to the vane stage or rotor stage of the turbine section, or both.

Abstract: An aircraft propulsion system is provided that includes a turbine engine and an exhaust gas condenser. The exhaust gas condenser includes a housing, a nozzle, a plurality of air scoops, and a plurality of exhaust gas conduit banks. The housing has an interior cavity, a bottom side, and first and second lateral sides. The exhaust gas conduit banks are disposed in the interior cavity of the housing and are configured to form an interior bypass air chamber. Each exhaust gas conduit bank includes alternating exhaust gas conduits and bypass air passages. The exhaust gas conduits extend axially between the forward and aft ends, and are configured to conduct exhaust gases to the nozzle. The bypass air passages are configured to receive bypass air from the air scoops and direct the bypass air between the exhaust gas conduits and into the interior bypass air chamber.

Abstract: An aircraft propulsion system is provided that includes a turbine engine and an exhaust gas condenser. The exhaust gas condenser includes a housing, a nozzle, inlet and outlet air scoops, and an exhaust gas conduit bank. The housing has an interior cavity, top and bottom sides, and first and second lateral sides. The exhaust gas conduit bank is disposed in the interior cavity of the housing. The exhaust gas conduit bank includes a plurality of exhaust gas conduits and bypass air passages that are disposed in an alternating configuration. The exhaust gas conduits extend axially between the forward and aft ends, are open at the forward end and at the nozzle. The bypass air passages receive bypass air from the inlet air scoop and direct the bypass air laterally across the condenser to the outlet air scoop.

Abstract: An aircraft propulsion system is provided that includes a turbine engine and an exhaust gas condenser. The exhaust gas condenser includes a housing, a nozzle, air scoops, a bank of exhaust gas conduits, and a center collection channel. The housing includes an interior cavity, top and bottom sides, and first and second lateral sides. The bank of exhaust gas conduits is disposed in the interior cavity of the housing and includes exhaust gas conduits and bypass air passages. The exhaust gas conduits and bypass air passages are disposed in an alternating configuration. The center collection channel is disposed radially inside of the bank of exhaust conduits. The exhaust gas conduits and bypass air passages extend spirally along the central axis between the forward and aft ends. Each bypass air passage is in fluid communication with an air scoop and the center collection channel.

Abstract: A system is provided for an aircraft. This aircraft system includes an aircraft powerplant, a powerplant sensor system, an environment sensor system and a monitoring system. The aircraft powerplant includes a heat engine. The powerplant sensor system is configured to provide engine data indicative of one or more operating parameters of the heat engine. The environment sensor system is configured to provide environment data indicative of one or more environmental parameters of an environment in which the heat engine is operating. The monitoring system is configured to determine formation of a contrail and quantify an impact of the contrail when formed based on the engine data and the environment data.

Abstract: A diffuser nozzle for a gas turbine engine includes a housing disposed about a nozzle axis and extending between a first nozzle end and a second nozzle end. The housing defines a nozzle duct. A plurality of walls is disposed within the nozzle duct. The plurality of walls subdivides the nozzle duct into a plurality of duct sections. The plurality of walls further defines a plurality of axially-extending duct segments of the nozzle duct such that within a first axially-extending duct segment, the duct cross-sectional area of a first duct section of the plurality of duct sections is greater than the duct cross-sectional area of each other duct section and within a second axially-extending duct segment, the duct cross-sectional area of a second duct section of the plurality of duct sections is greater than the duct cross-sectional area of each other duct section.

Abstract: A gas turbine engine for an aircraft includes a turbine section and an exhaust section configured to receive an exhaust gas stream from the turbine section. The exhaust section includes a monolithic catalyst structure configured to remove nitrogen oxides (NOx) from the exhaust gas stream.

Abstract: A diffuser nozzle for a gas turbine engine includes a housing disposed about a nozzle axis and extending between a first nozzle end and a second nozzle end. The housing defines a nozzle duct. A plurality of walls is disposed within the nozzle duct. The plurality of walls subdivides the nozzle duct into a plurality of duct sections. The plurality of walls further defines a plurality of axially-extending duct segments of the nozzle duct such that within a first axially-extending duct segment, the duct cross-sectional area of a first duct section of the plurality of duct sections is greater than the duct cross-sectional area of each other duct section and within a second axially-extending duct segment, the duct cross-sectional area of a second duct section of the plurality of duct sections is greater than the duct cross-sectional area of each other duct section.