Hydrogen liquid oxygen combined cycle engine

Patent metadata

Field	Value
Publication number	US-2025271142-A1
Application number	US-202519076381-A
Country	US
Kind code	A1
Filing date	Mar 11, 2025
Priority date	Jun 27, 2023
Publication date	Aug 28, 2025
Grant date	—

Abstract

A propulsion system for an air vehicle includes a fan system that includes a fan that is coupled to a fan drive electric motor for generating a fan discharge airflow, an augmentor where fuel is mixed with a portion of the fan discharge airflow to generate a propulsive flow in a first operating configuration, a bypass duct for directing the fan discharge airflow into the augmentor, a duct blocker for selectively closing the bypass duct to the fan discharge airflow, a liquid oxygen system that is configured to inject liquid oxygen into the augmentor to mix with the fuel when the fan discharge airflow is closed by the duct blocker, the mixture of fuel flow and liquid oxygen generates the propulsive flow in a second operating configuration, and an electric power generation system is coupled to drive the fan drive electric motor.

First claim

1 - 19 . (canceled)

20 . A propulsion system for an air vehicle comprising:
a fan system comprising a fan coupled to a fan drive electric motor for generating a fan discharge airflow; an inlet movable between an open position allowing inlet airflow to the fan system and a closed position shutting inlet airflow to the fan system, an augmentor where fuel is mixed with a portion of the fan discharge airflow to generate a propulsive flow in a first operating configuration; a bypass duct for directing the fan discharge airflow into the augmentor; a duct blocker for selectively closing the bypass duct to the fan discharge airflow; a liquid oxygen system configured to inject liquid oxygen into the augmentor to mix with the fuel when the fan discharge airflow is closed by the duct blocker, wherein the mixture of fuel flow and liquid oxygen generates the propulsive flow in a second operating configuration; and an electric power generation system comprising a combustor where exhaust gas flows are mixed with fuel and liquid oxygen to generate an exhaust gas flow that is expanded through a free turbine, wherein the free turbine is coupled to drive a generator that provides electric power to the fan drive electric motor to drive the fan drive electric motor.

21 . The propulsion system as recited in claim 20 , wherein the inlet translates axially between the open position and the closed position.

22 . The propulsion system as recited in claim 20 , including a fuel pump for pressurizing a fuel flow to the combustor and an oxidizer pump for pressurizing a liquid oxygen flow to the combustor.

23 . The propulsion system as recited in claim 22 , wherein the fuel pump comprises a fuel turbopump and the oxidizer pump comprises an oxidizer turbopump, both the fuel turbopump and the oxidizer turbopump are configured to be driven by a hot gas flow generated by combustion of a mixture of fuel and oxidizer.

24 . The propulsion system as recited in claim 22 , wherein the fuel pump is driven by a first electric motor and the oxidizer pump is driven by a second electric motor.

25 . The propulsion system as recited in claim 20 , including a gearbox driven by the free turbine and including an output coupled to drive the generator.

26 . The propulsion system as recited in claim 20 , wherein the propulsive flow is expelled through a converging diverging nozzle.

27 . The propulsion system as recited in claim 20 , wherein the propulsion system is configured to operate in a first operating configuration where the fan generates a fan discharge flow through the augmenter and in a second operating configuration where the inlet is closed and the propulsive flow is generated by combustion of a mixture of fuel and liquid oxygen in the augmentor.

28 . The propulsion system as recited in claim 20 , wherein the fan of the fan system comprises a multi-stage fan.

29 . The propulsion system as recited in claim 20 , wherein the fuel comprises one of a liquid hydrogen fuel.

30 . The propulsion system as recited in claim 20 , wherein a propellant communicated to the combustor comprises at least one of a combination of kerosene-oxygen, methane-oxygen, and Aerozine 50 (hydrazine)-nitrogen tetra-oxide

31 . An aircraft propulsion system comprising:
a fan system including a fan rotatable about an engine axis and coupled to a fan drive electric motor configured to generate a fan discharge flow; an inlet movable between an open position allowing inlet airflow to the fan system and a closed position closing off inlet airflow to the fan system; a fuel system providing a flow of fuel; an augmentor configured to generate a propulsive gas flow from a mixture of fuel and the fan discharge airflow in a first engine operating configuration; a duct blocker movable between an open and a closed position for controlling the fan discharge flow to the augmentor; and a liquid oxygen system configured to provide oxygen to the augmentor to mix with the fuel and generate the propulsive gas flow in a second engine operating configuration, wherein in the second engine operating configuration, the duct blocker is in a closed position such that no fan discharge flow is communicated to the augmentor; and an electric power generation system includes a combustor for generating an exhaust gas flow by igniting a mixture of fuel and liquid oxygen, a free turbine section configured to be driven by the exhaust gas flow from the combustor, and an electric generator driven by the free turbine to provide electric power to the fan drive electric motor.

32 . The aircraft propulsion system as recited in claim 31 , wherein the electric power generation system further comprises a fuel pump for pressurizing a fuel flow communicated to the combustor and an oxidizer pump for pressurizing a liquid oxygen flow to the combustor.

33 . The aircraft propulsion system as recited in claim 32 , wherein the fuel pump comprises a fuel turbopump and the oxidizer pump comprises an oxidizer turbopump, wherein each of the fuel turbopump and the oxidizer turbopump are driven by a hot gas flow.

34 . The aircraft propulsion system as recited in claim 31 , wherein the fan of the fan system comprises a multi-stage fan.

35 . A method of operating an aircraft propulsion system comprising:
generating electric power with a free turbine driven generator rotatable about an engine axis; driving a fan about the engine axis with an electric motor to generate a fan discharge flow in a first engine operating configuration, wherein the electric motor is driven by the generated electric power from the generator; mixing the fan discharge airflow with fuel in an augmentor to generate a propulsive gas flow exhausted through a nozzle in the first engine operating configuration; and closing off an inlet flow to the fan, closing off the fan discharge airflow to the augmentor, and communicating an oxygen flow to the augmentor for mixing with the fuel to generate the propulsive gas flow that is exhausted through the nozzle in a second engine operating configuration.

36 . The method as recited in claim 35 , wherein generating electric power comprises generating an exhaust gas flow from a flow of liquid oxygen and fuel ignited in a combustor for driving the free turbine in an electricity generation system separate from the fan.

37 . The method as recited in claim 35 , further comprising controlling inlet flow to the fan with a translating inlet, wherein the translating inlet is open in the first engine operating configuration and closed in the second engine operating configuration.

38 . The method as recited in claim 35 , further comprising operating in the first engine operating configuration for a first set of flight conditions and operating in the second engine operating configuration for a second set of flight conditions and transitioning between the first engine operating configuration to the second engine operating configuration by closing fan discharge airflow to the augmentor and communicating a liquid oxygen flow to the augmentor.

Assignees

• Rtx Corp

Inventors

• Ledwith Jr Walter A
• Lei Ma David

Classifications

• F05D2220/36

  specially adapted for the fan of turbofan engines · CPC title

• F02C9/18

  by bleeding, bypassing or acting on variable working fluid interconnections between turbines or compressors or their stages {(F02C3/113 takes precedence)} · CPC title

• F02C7/22

  Fuel supply systems · CPC title

• F01D15/10

  Adaptations for driving, or combinations with, electric generators · CPC title

• F05D2220/76

  an electrical generator · CPC title