US-12624660-B1 - Hybrid aircraft power plant with ventilated exhaust duct cavity

Abstract

A hybrid aircraft power plant includes an air mover for propelling an aircraft, a gas turbine engine operable to drive the air mover, and an electric machine operable as a motor to drive the air mover. The gas turbine engine includes a turbine disk for extracting energy from a stream of combustion gas and an exhaust duct defining: an exhaust passage for conveying the stream of combustion gas from the turbine disk; and a cavity disposed radially inward of the exhaust passage. A shaft drivingly connects the turbine disk with the electric machine and extends inside the cavity defined by the exhaust duct. A fan is drivingly connected to the shaft and operable to circulate cooling air inside the cavity of the exhaust duct.

Inventors

• Michel Labrecque
• Bruno Chatelois
• Eric S. DUROCHER

Assignees

• PRATT & WHITNEY CANADA CORP.

Dates

Publication Date

20260512

Application Date

20250320

Claims (17)

1. 1 . A hybrid aircraft power plant comprising: an air mover for propelling an aircraft; a gas turbine engine operable to drive the air mover, the gas turbine engine including: a turbine disk operable to extract energy from an annular stream of combustion gas, the turbine disk being rotatable about a rotation axis; an exhaust duct defining: an exhaust passage disposed radially outward of the rotation axis for receiving the annular stream of the combustion gas from the turbine disk and conveying the combustion gas away from the turbine disk; and a cavity disposed radially inward of the exhaust passage; a shaft drivingly connected to the turbine disk and extending inside the cavity defined by the exhaust duct; and a fan drivingly connected to the shaft and operable to circulate cooling air inside the cavity defined by the exhaust duct; and an electric machine drivingly connected to the turbine disk via the shaft and operable as a motor to drive the air mover via the shaft, wherein: the fan includes a bladed rotor driven by the shaft; the fan is closer to the electric machine than to the turbine disk; and the blades of the bladed rotor are oriented to propel the cooling air at the fan axially toward the turbine disk.
2. 2 . The hybrid aircraft power plant as defined in claim 1 , wherein: a rotor of the electric machine is coaxial with the turbine disk; the shaft is coaxial with the turbine disk; and the turbine disk is disposed between the electric machine and the air mover.
3. 3 . The hybrid aircraft power plant as defined in claim 2 , wherein the fan is disposed inside of the cavity defined by the exhaust duct and between the electric machine and the turbine disk.
4. 4 . The hybrid aircraft power plant as defined in claim 2 , wherein the bladed rotor is mounted for common rotation with the shaft.
5. 5 . The hybrid aircraft power plant as defined in claim 4 , comprising a stator vane fixedly mounted to the exhaust duct inside of the cavity defined by the exhaust duct, for interacting with a flow of the cooling air upstream of the bladed rotor of the fan.
6. 6 . The hybrid aircraft power plant as defined in claim 2 , wherein: the electric machine is mounted to the exhaust duct; and the electric machine is disposed outside of the cavity defined by the exhaust duct.
7. 7 . The hybrid aircraft power plant as defined in claim 1 , wherein the bladed rotor is mounted for common rotation with the shaft.
8. 8 . The hybrid aircraft power plant as defined in claim 1 , wherein the exhaust duct defines an opening providing fluid communication between the cavity defined by the exhaust duct and a source of the cooling air.
9. 9 . The hybrid aircraft power plant as defined in claim 8 , wherein: the gas turbine engine is housed inside a nacelle; and the source of cooling air includes a space between the nacelle and the gas turbine engine.
10. 10 . The hybrid aircraft power plant as defined in claim 8 , wherein: the gas turbine engine is housed inside a nacelle; and the source of cooling air includes an ambient environment outside of the nacelle.
11. 11 . The hybrid aircraft power plant as defined in claim 8 , wherein: the gas turbine engine includes a compressor; and the source of cooling air includes the compressor of the gas turbine engine.
12. 12 . The hybrid aircraft power plant as defined in claim 1 , comprising an inlet scroll operable to deliver the cooling air to the fan.
13. 13 . A hybrid aircraft power plant comprising: a propeller for propelling the aircraft; a compressor for pressurizing air; a combustor in which the pressurised air is mixed with fuel and ignited for generating combustion gas; a turbine disk for extracting energy from combustion gas, the turbine disk having a rotation axis and being in torque-transmitting engagement with the propeller; an exhaust duct for receiving the combustion gas from the turbine disk, the exhaust duct defining: an exhaust passage disposed radially outward of the rotation axis of the turbine disk for receiving the combustion gas from the turbine disk and conveying the combustion gas away from the turbine disk; and a cavity fluidly isolated from the exhaust passage and disposed radially inward of the exhaust passage; an electric machine in torque-transmitting engagement with the turbine disk via a shaft extending inside the cavity defined by the exhaust duct; and a fan operable to ventilate the cavity defined by the exhaust duct, the fan including a bladed rotor mounted for common rotation with the shaft and configured to propel cooling air at the fan toward the turbine disk, the fan being closer to the electric machine than to the turbine disk.
14. 14 . The hybrid aircraft power plant as defined in claim 13 , wherein: the propeller is operable to propel the aircraft in a forward direction; the exhaust duct is disposed aft of the turbine disk; and the electric machine is disposed aft of the cavity defined by the exhaust duct.
15. 15 . The hybrid aircraft power plant as defined in claim 14 , wherein: the electric machine is coaxial with the turbine disk; the shaft is coaxial with the turbine disk; the turbine disk is disposed between the electric machine and the propeller; and the bladed rotor of the fan is disposed between the electric machine and the turbine disk.
16. 16 . A method of propelling an aircraft, the method comprising: extracting energy from combustion gas using a turbine; driving an air mover with the turbine to propel the aircraft; conveying the combustion gas from the turbine in an exhaust passage of an exhaust duct; driving the air mover with an electric motor via a shaft drivingly connecting the electric motor to the turbine, the shaft extending inside a cavity of the exhaust duct that is fluidly isolated from the exhaust passage of the exhaust duct; and driving a fan with the shaft to circulate cooling air inside of the cavity of the exhaust duct, wherein: driving the air mover with the turbine to propel the aircraft includes propelling the aircraft in a forward direction; driving the fan includes propelling the cooling air at the fan in the forward direction inside of the cavity of the exhaust duct; and the fan is closer to the electric motor than to the turbine.
17. 17 . The method as defined in claim 16 , wherein driving the fan includes rotating a bladed rotor of the fan together and coaxially with the shaft.

Description

TECHNICAL FIELD The disclosure relates generally to hybrid aircraft power plants, and more particularly to architectures of hybrid aircraft power plants. BACKGROUND A hybrid aircraft power plant that includes a heat engine and an electric motor for propelling an aircraft can provide operational advantages. However, the implementation of hybrid aircraft power plants can be challenging and can result in system architectures that are complex and bulky. Improvement is desirable. SUMMARY In one aspect, the disclosure describes a hybrid aircraft power plant comprising: an air mover for propelling an aircraft; a gas turbine engine operable to drive the air mover. The gas turbine engine includes: a turbine disk operable to extract energy from an annular stream of combustion gas, the turbine disk being rotatable about a rotation axis;an exhaust duct defining: an exhaust passage disposed radially outward of the rotation axis for receiving the annular stream of the combustion gas from the turbine disk and conveying the combustion gas away from the turbine disk; and a cavity disposed radially inward of the exhaust passage;a shaft drivingly connected to the turbine disk and extending inside the cavity defined by the exhaust duct; anda fan drivingly connected to the shaft and operable to circulate cooling air inside the cavity defined by the exhaust duct; andan electric machine drivingly connected to the turbine disk via the shaft and operable as a motor to drive the air mover via the shaft. A rotor of the electric machine may be coaxial with the turbine disk. The shaft may be coaxial with the turbine disk. The turbine disk may be disposed between the electric machine and the air mover. The fan may be disposed inside of the cavity defined by the exhaust duct and between the electric machine and the turbine disk. The fan may include a bladed rotor that is mounted for common rotation with the shaft. The fan may be closer to the electric machine than to the turbine disk. The blades of the bladed rotor may be oriented to propel the cooling air axially toward the turbine disk. The hybrid aircraft power plant may include a stator vane fixedly mounted to the exhaust duct inside of the cavity defined by the exhaust duct, for interacting with a flow of the cooling air upstream of the bladed rotor of the fan. The electric machine may be mounted to the exhaust duct. The electric machine may be disposed outside of the cavity defined by the exhaust duct. The fan may include a bladed rotor that is mounted for common rotation with the shaft. The exhaust duct may define an opening providing fluid communication between the cavity defined by the exhaust duct and a source of the cooling air. The gas turbine engine may be housed inside a nacelle. The source of cooling air may include a space between the nacelle and the gas turbine engine. The gas turbine engine may be housed inside a nacelle. The source of cooling air may include an ambient environment outside of the nacelle. The gas turbine engine may include a compressor. The source of cooling air may include the compressor of the gas turbine engine. The hybrid aircraft power plant may include an inlet scroll operable to deliver the cooling air to the fan. Embodiments may include combinations of the above features. In another aspect, the disclosure describes a hybrid aircraft power plant comprising: a propeller for propelling the aircraft;a compressor for pressurizing air;a combustor in which the pressurised air is mixed with fuel and ignited for generating combustion gas;a turbine disk for extracting energy from combustion gas, the turbine disk having a rotation axis and being in torque-transmitting engagement with the propeller;an exhaust duct for receiving the combustion gas from the turbine disk, the exhaust duct defining: an exhaust passage disposed radially outward of the rotation axis of the turbine disk for receiving the combustion gas from the turbine disk and conveying the combustion gas away from the turbine disk; and a cavity fluidly isolated from the exhaust passage and disposed radially inward of the exhaust passage;an electric machine in torque-transmitting engagement with the turbine disk via a shaft extending inside the cavity defined by the exhaust duct; anda fan operable to ventilate the cavity defined by the exhaust duct, the fan including a bladed rotor mounted for common rotation with the shaft. The propeller may be operable to propel the aircraft in a forward direction. The exhaust duct may be disposed aft of the turbine disk. The electric machine may be disposed aft of the cavity defined by the exhaust duct. The electric machine may be coaxial with the turbine disk. The shaft may be coaxial with the turbine disk. The turbine disk may be disposed between the electric machine and the propeller. The bladed rotor of the fan may be disposed between the electric machine and the turbine disk. Embodiments may include combinations of the above features. In a further aspect,