Turbomachine with unducted dual propellers

Patent metadata

Field	Value
Publication number	US-11987369-B2
Application number	US-201917288206-A
Country	US
Kind code	B2
Filing date	Oct 25, 2019
Priority date	Oct 26, 2018
Publication date	May 21, 2024
Grant date	May 21, 2024

Abstract

A turbomachine of an aircraft comprising an outer casing delimiting with an inner hub, a flow path of a gas stream in which is disposed a low-pressure turbine configured to rotationally drive a low-pressure shaft; said turbomachine comprising, in the direction of flow of the gas stream, a first propeller; and a second propeller downstream of the first propeller, the first propeller being rotationally driven by said low-pressure shaft and the second propeller being rotationally driven by an electric motor, the second propeller being further disposed at a distance between 1.5 and 4 cord lengths from the first propeller defined between the respective axes of shimming of each of the first and second propellers.

First claim

The invention claimed is:

1. A turbomachine of an aircraft,
the turbomachine comprising:
an inner hub,
a low-pressure shaft,
a low pressure turbine configured to rotationally drive the low-pressure shaft,
an outer casing delimiting with the inner hub a flow path of a gas stream in which is disposed the low-pressure turbine, and
an electric motor/generator,
a first propeller, having a first axis of shimming, configured to be rotationally driven by the low-pressure shaft; and
a second propeller, having a second axis of shimming, downstream of and coaxial with the first propeller, and configured to be rotationally driven by the electric motor/generator,
the second propeller being disposed at a distance between 1.5 and 4 cord lengths from the first propeller, the distance being defined between the respective axes of shimming of each of the first and second propellers using a cord length of the first propeller.

2. A turbomachine as claimed in claim 1 , wherein the second propeller has an outer diameter between 0.8 and 1 times an outer diameter of the first propeller.

3. A turbomachine as claimed in claim 1 , wherein blades of the second propeller extend from the inner hub, the second propeller having a hub radius to outer blade radius ratio between 0.22 and 0.40.

4. A turbomachine as claimed in claim 1 , wherein the second propeller has a cord length between 0.8 and 1.2 times the cord length of the first propeller.

5. A turbomachine as claimed in claim 1 ,
the electric motor/generator being a second electric motor,
wherein the turbomachine further comprises a first electric motor/generator configured to contribute to rotationally drive the low-pressure shaft,

the first propeller being configured to be rotationally driven by the low-pressure shaft by way of a reduction gear.

6. A turbomachine as claimed in claim 1 , further comprising a power storage unit connected to the electric motor/generator.

7. The turbomachine as claimed in claim 6 wherein the power storage unit has a capacity between 200 and 500 kWh.

8. A turbomachine as claimed in claim 1 , wherein the first and the second propellers are disposed in front of an inlet of the flow path of the gas stream.

9. A turbomachine as claimed in claim 1 , wherein the first and the second propellers are disposed downstream of the flow path and outside the flow path of the gas stream.

10. A propulsive system comprising a turbomachine as claimed in claim 1 , and further comprising a power storage unit connected to the electric motor/generator.

11. The propulsive system as claimed in claim 10 , wherein the power storage unit has a capacity between 200 and 500 kWh.

12. The turbomachine as claimed in claim 1 , further comprising:
a gas generator,
a unit for controlling the electric motor/generator, and
a unit for controlling an angle of shimming of the second propeller,
the controlling units being configured to control the electric motor/generator and the angle of shimming of the second propeller according to one of the following operating modes:
a first operating mode requiring a first given propulsive power wherein the electric motor/generator rotationally drives the second propeller in an opposite direction to the first propeller and the angle of shimming of the second propeller is controlled so that the second propeller supplies between 20% and 40% of the first given propulsive power;
a second operating mode requiring a second given propulsive power wherein the electric motor/generator does not rotationally drive the second propeller and the angle of shimming of the second propeller is controlled in such a way as to maximize a propulsive efficiency of the turbomachine;
a third operating mode requiring a third given propulsive power wherein the gas generator and the first propeller are regulated in such a way as to supply a propulsive power greater than the third given propulsive power;
a fourth operating mode wherein an angle of shimming of the first propeller is positioned at a negative angle and wherein the second propeller is controlled with windmilling, the gas generator operating in a high-pressure reduced speed range wherein a flow rate of fuel injected into a combustion chamber of the gas generator is between 90% and 100% of a nominal flow rate of the gas generator, and wherein the first propeller is in thrust reversal and the second propeller allows a reversal of an air stream feeding the first propeller;
a fifth operating mode wherein an overall level of thrust is maintained by an exclusively electrical supply of power to the second propeller during a given time period; and
a sixth operating mode wherein:
if a control of the angle of shimming of the second propeller is defective, then the angle of shimming of the second propeller is blocked; and
if the second electric motor/generator of the second propeller is defective, then the second propeller is controlled to be in free wheel.

13. The turbomachine as claimed in claim 12 , wherein in the third operating mode the angle of shimming of the second propeller is controlled in such a way as to obtain an angle of incidence of the blades less than 0° in order to rotationally drive the second propeller in a direction of rotation opposite to a direction of rotation of the first propeller.

14. The turbomachine as claimed in claim 12 , wherein in the third operating mode the angle of shimming of the second propeller is controlled in such a way as to obtain an angle of incidence of the blades greater than 0° in order to rotationally drive the second propeller in a direction of rotation identical to the direction of rotation of the first propeller.

15. A turbomachine of an aircraft,
the turbomachine comprising:
an inner hub,
a low-pressure shaft,
a low pressure turbine configured to rotationally drive the low-pressure shaft,
an outer casing delimiting with the inner hub a flow path of a gas stream in which is disposed the low-pressure turbine, and
an electric motor/generator,
a first propeller, having a first axis of shimming, configured to be rotationally driven by the low-pressure shaft; and
a second propeller, having a second axis of shimming, downstream of and coaxial with the first propeller, and configured to be rotationally driven by the electric motor/generator via a first reduction gear,
the second propeller being disposed at a distance between 1.5 and 4 cord lengths from the first propeller, the distance being defined between the respective axes of shimming of each of the first and second propellers using a cord length of the first propeller.

Assignees

• Safran Aircraft Engines

Inventors

• Tantot Nicolas Jérôme Jean
• Binder Anthony
• Lambey Mario Antoine

Classifications

• B64D27/35

  Arrangements for on-board electric energy production, distribution, recovery or storage · CPC title

• B64D27/33

  Hybrid electric aircraft · CPC title

• B64D27/10 Primary

  of gas-turbine type  (jet aircraft B64D27/16) · CPC title

• F02K3/072 Primary

  with counter-rotating {, e.g. fan} rotors · CPC title

• F05D2220/76

  an electrical generator · CPC title