Auxiliary drive bowed rotor prevention system for a gas turbine engine through an engine accessory

Patent metadata

Field	Value
Publication number	US-10508567-B2
Application number	US-201615161450-A
Country	US
Kind code	B2
Filing date	May 23, 2016
Priority date	Feb 12, 2016
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A bowed rotor prevention system for a gas turbine engine of an aircraft is provided. The bowed rotor prevention system includes a gear train and a bowed rotor prevention motor. The gear train is coupled through an engine accessory to an engine accessory gearbox that is further coupled to a starting spool of the engine. The bowed rotor prevention motor is operable to drive rotation of the starting spool of the gas turbine engine through the gear train upon engine shutdown.

First claim

The invention claimed is:

1. A bowed rotor prevention system for a gas turbine engine of an aircraft, the bowed rotor prevention system comprising:
an engine accessory comprising a pump;
a gear train coupled through the engine accessory to an engine accessory gearbox that is further coupled to a starting spool of the engine, wherein the gear train comprises a transmission with an epicyclic gear set coupled to a drive portion of the engine accessory; and
a bowed rotor prevention motor operable to drive rotation of the starting spool of the gas turbine engine through the drive portion of the engine accessory and the gear train upon engine shutdown, wherein the transmission is interposed between the bowed rotor prevention motor and the engine accessory gearbox.

2. The bowed rotor prevention system as in claim 1 , wherein the gear train comprises a back-drive preventer that isolates the bowed rotor prevention motor from rotatable components of the gas turbine engine to inhibit the bowed rotor prevention motor from being back-driven.

3. The bowed rotor prevention system as in claim 2 , wherein the back-drive preventer is a clutch.

4. The bowed rotor prevention system as in claim 1 , wherein the bowed rotor prevention motor is an electric motor.

5. The bowed rotor prevention system as in claim 4 , wherein an energy storage source is used to drive the electric motor, and the energy storage source is rechargeable by a generator on an aircraft electrical system.

6. The bowed rotor prevention system as is claim 4 , wherein the bowed rotor prevention motor is further operable to be driven by electrical power from an auxiliary energy source.

7. The bowed rotor prevention system as in claim 1 , wherein the bowed rotor prevention motor is further operable to drive rotation of the starting spool until a bowed rotor prevention shutdown request is detected, wherein the bowed rotor prevention shutdown request is detected based on one or more of: a detected opening of a nacelle of the gas turbine engine, a shutoff switch accessible to maintenance personnel on the nacelle or the gas turbine engine, a computer interface command on the aircraft, a detected fault condition, a time limit, a temperature limit, or a start command of the gas turbine engine.

8. The bowed rotor prevention system as in claim 1 , wherein the epicyclic gear set has a reduction ratio between 100:1 and 10,000:1.

9. The bowed rotor prevention system as in claim 1 , wherein the epicyclic gear set is integrated with the engine accessory.

10. The bowed rotor prevention system as in claim 1 , further comprising a delay circuit operable to delay activation of the bowed rotor prevention motor upon engine shutdown.

11. A gas turbine engine of an aircraft, the gas turbine engine comprising:
a starting spool coupled to an engine accessory gearbox;
a gear set coupled through an engine accessory to the engine accessory gearbox, wherein the engine accessory comprises a pump, and the gear set comprises a transmission coupled to a drive portion of the engine accessory; and
a bowed rotor prevention motor operable to drive rotation of the starting spool through the gear set and the drive portion of the engine accessory gearbox upon engine shutdown, wherein the transmission is interposed between the bowed rotor prevention motor and the engine accessory gearbox.

12. The gas turbine engine of claim 11 , wherein the bowed rotor prevention motor is further operable to drive rotation of the starting spool until a bowed rotor prevention shutdown request is detected, wherein the bowed rotor prevention shutdown request is detected based on one or more of: a detected opening of a nacelle of the gas turbine engine, a shutoff switch accessible to maintenance personnel on the nacelle or the gas turbine engine, a computer interface command on the aircraft, a detected fault condition, a time limit, a temperature limit, or a start command of the gas turbine engine.

13. The gas turbine engine of claim 11 , wherein the gear set is an epicyclic gear set, and the gear set comprises an over-running clutch to prevent the bowed rotor prevention motor from being back-driven.

14. The gas turbine engine of claim 11 , wherein the gear set is integrated with the engine accessory.

15. A method for bowed rotor prevention for a gas turbine engine of an aircraft, the method comprising:
engaging a bowed rotor prevention motor with a starting spool of the gas turbine engine using a gear train coupled through an engine accessory to an engine accessory gearbox, wherein the engine accessory comprises a pump, and the gear train comprises a transmission with an epicyclic gear set coupled to a drive portion of the engine accessory; and
driving rotation of the starting spool by the bowed rotor prevention motor through the drive portion of the engine accessory and the gear train upon engine shutdown, wherein the transmission is interposed between the bowed rotor prevention motor and the engine accessory gearbox.

16. The method as in claim 15 , wherein the bowed rotor prevention motor is an electric motor and an energy storage source operable to drive the electric motor is a battery or a capacitor, and the method further comprises:
recharging the energy storage source using a generator on an aircraft electrical system.

17. The method as in claim 15 , further comprising:
driving rotation of the starting spool until a bowed rotor prevention shutdown request is detected, wherein the bowed rotor prevention shutdown request is detected based on one or more of: a detected opening of a nacelle of the gas turbine engine, a shutoff switch accessible to maintenance personnel on the nacelle or the gas turbine engine, a computer interface command on the aircraft, a detected fault condition, a time limit, a temperature limit, or a start command of the gas turbine engine.

18. The method as in claim 15 , further comprising:
delaying activation of the bowed rotor prevention motor upon engine shutdown through a delay circuit.

Assignees

• United Technologies Corp

Inventors

• Stachowiak David Allen
• Sheridan William G

Classifications

• F01D21/00

  Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for · CPC title

• F01D25/36 Primary

  using electric motors · CPC title

• F02C7/32

  Arrangement, mounting, or driving, of auxiliaries · CPC title

• B64D27/16

  of jet type · CPC title

• B64D2041/002

  Mounting arrangements for auxiliary power units (APU's) · CPC title