Low-power bowed rotor prevention system

Patent metadata

Field	Value
Publication number	US-10598047-B2
Application number	US-201715444942-A
Country	US
Kind code	B2
Filing date	Feb 28, 2017
Priority date	Feb 29, 2016
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

A bowed rotor prevention system for a gas turbine engine includes a core turning motor operable to drive rotation of an engine core of the gas turbine engine. The bowed rotor prevention system also includes an auxiliary electric motor control operable to control the core turning motor to drive rotation of the engine core using electric power while a full authority digital engine control that controls operation of the gas turbine engine is either depowered or in a power state that is less than a power level used by the full authority digital engine control in flight operation.

First claim

The invention claimed is:

1. A bowed rotor prevention system for a gas turbine engine, the bowed rotor prevention system comprising:
a core turning motor configured to drive rotation of an engine core of the gas turbine engine; and
an auxiliary electric motor control configured to:
control the core turning motor to drive rotation of the engine core using electric power while a full authority digital engine control (FADEC) that controls operation of the gas turbine engine is either depowered or in a power state that is less than a power level used by the FADEC in flight operation, and
report a success status to the FADEC indicating whether a bowed rotor prevention process was successfully or unsuccessfully completed;

wherein the FADEC is configured to perform a dry motoring process at start-up based on the report from the auxiliary electric motor control indicating that a bowed rotor prevention process was unsuccessfully completed using the core turning motor, the dry motoring process comprising actively adjusting a starter valve by the FADEC to deliver air pressure from an air supply to an air turbine starter that drives rotation of a starting spool of the engine core to a dry motoring speed that is lower than a starting speed.

2. The bowed rotor prevention system as in claim 1 , further comprising a switch interposed between the auxiliary electric motor control and an electric power source that provides aircraft power, wherein the core turning motor is an electric motor and the auxiliary electric motor control is operable to control a flow of electric current between the electric power source and the core turning motor based on a state of the switch.

3. The bowed rotor prevention system as in claim 1 , wherein the FADEC is operable to enable the auxiliary electric motor control based on detecting an engine shutdown condition of the gas turbine engine.

4. The bowed rotor prevention system as in claim 3 wherein the FADEC delays enabling of the auxiliary electric motor control alter detecting the engine shutdown condition.

5. The bowed rotor prevention system as in claim 1 , wherein the core turning motor is mechanically linked through a transmission system to the engine core.

6. The bowed rotor prevention system as in claim 5 , wherein the transmission system comprises a gear train and a back-drive preventer.

7. The bowed rotor prevention system as in claim 1 , wherein the core turning motor is capable of a continuous stall torque and continuous free run.

8. The bowed rotor prevention system as in claim 1 , wherein the auxiliary electric motor control is operable to monitor an operational status of the core turning motor to report the success status to the FADEC.

9. The bowed rotor prevention system as in claim 1 , wherein the auxiliary electric motor control is operable to control the core turning motor to drive rotation of the engine core at a constant speed for a timed duration.

10. The bowed rotor prevention system as in claim 9 , wherein the constant speed is 0.1 revolutions per minute.

11. The bowed rotor prevention system as in claim 1 , wherein the engine core is a high spool of the gas turbine engine.

12. The bowed rotor prevention system as in claim 1 , wherein the auxiliary electric motor control is in a physically separate enclosure as the FADEC.

13. The bowed rotor prevention system as in claim 1 , wherein the auxiliary electric motor control is located within a FADEC chassis shared by a plurality of resources of the FADEC.

14. The bowed rotor prevention system as in claim 1 , wherein the auxiliary electric motor control and the core turning motor consume between 40 and 500 watts while driving rotation of the engine core.

15. The bowed rotor prevention system as in claim 1 , wherein the auxiliary electric motor control and the core turning motor consume about 40 watts while driving rotation of the engine core.

16. The bowed rotor prevention system as in claim 1 , wherein the core turning motor is shut down 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 of the gas turbine engine, a computer interface command on an aircraft, a detected fault condition, a time limit, a temperature limit, or a start command of the gas turbine engine.

17. A method of bowed rotor prevention for a gas turbine engine, the method comprising:
engaging a core turning motor with turbomachinery of the gas turbine engine;
controlling the core turning motor by an auxiliary electric motor control to rotate the turbomachinery of the gas turbine engine using electric power while a full authority digital engine control (FADEC) that controls operation of the gas turbine engine is either depowered or in a power state that is less than a power level used by the FADEC in flight operation;
reporting a success status from the auxiliary electric motor control to the FADEC indicating whether a bowed rotor prevention process was successfully or unsuccessfully completed; and
performing a dry motoring process by the FADEC at start-up based on the report from the auxiliary electric motor control indicating that a bowed rotor prevention process was unsuccessfully completed using the core turning motor, the dry motoring process comprising actively adjusting a starter valve by the FADEC to deliver air pressure from an air supply to an air turbine starter that drives rotation of a starting spool of the engine core to a dry motoring speed that is lower than a starting speed.

18. The method as in claim 17 , wherein the core turning motor is an electric motor and the auxiliary electric motor control is operable to control a flow of electric current between an electric power source and the core turning motor based on a state of a switch interposed between the auxiliary electric motor control and the electric power source that provides aircraft power.

Assignees

• United Technologies Corp

Inventors

• Clauson Jesse W
• Schwarz Frederick M

Classifications

• F01D21/00

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

• F02C7/275

  Mechanical drives · CPC title

• F01D25/36 Primary

  using electric motors · CPC title

• F05D2260/4031

  as in toothed gearing · CPC title

• F02C7/32

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