Bowed rotor start using direct temperature measurement

• US 10,174,678 B2
• Filed: 02/12/2016
• Issued: 01/08/2019
• Est. Priority Date: 02/12/2016
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Schwarz, Frederick M., Grace, Amy R.
• Primary Examiner(s): Sutherland, Steven
• Application Number:
  US15/042,377
• Publication Number:
  US 20170234230A1
• Time in Patent Office: 1,061 Days
• CPC Class Codes: F01D 19/02 dependent on temperature of component parts, e.g. of turbine-casing
• CPC Class Codes: F01D 25/36 using electric motors
• CPC Class Codes: F02C 3/04 having a turbine driving a compressor power transmission arrangements F02C7/36; control of working fluid flow F02C9/16
• CPC Class Codes: F02C 7/26 Starting; Ignition
• CPC Class Codes: F02C 7/268 Starting drives for the rotor , acting directly on the rotor of the gas turbine to be started
• CPC Class Codes: F02C 9/00 Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants controlling air intakes F02C7/057; controlling turbines F01D; controlling compressors F04D27/00; controlling in general G05
• CPC Class Codes: F05D 2220/323 for aircraft propulsion, e.g. jet engines
• CPC Class Codes: F05D 2260/85 Starting
• CPC Class Codes: F05D 2260/941 particularly aimed at mechanical or thermal stress reduction
• CPC Class Codes: F05D 2270/54 by electronic means, e.g. electronic tubes, transistors or IC's within an electronic circuit
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence

Abstract

A bowed rotor start mitigation system for a gas turbine engine is provided. The bow rotor start mitigation system includes a controller operable to receive a speed input indicative of a rotor speed of the gas turbine engine and a measured temperature of the gas turbine engine. The controller is further operable to drive motoring of the gas turbine engine by oscillating the rotor speed within a motoring band for a motoring time based on the measured temperature when a start sequence of the gas turbine engine is initiated.

Claims

1. A bowed rotor start mitigation system for a gas turbine engine, the bowed rotor start mitigation system comprising:

a controller operable to receive a speed input indicative of a rotor speed of the gas turbine engine and a measured temperature of the gas turbine engine, the controller further operable to drive motoring of the gas turbine engine by oscillating the rotor speed within a motoring band for a motoring time based on the measured temperature when a start sequence of the gas turbine engine is initiated, wherein the motoring time is associated with a bowed rotor risk parameter that is determined based on the measured temperature using a mapping function or lookup table with a higher risk resulting in a longer duration to reduce a temperature gradient within the gas turbine engine.

2. The bowed rotor start mitigation system as in claim 1, wherein the motoring band comprises a range of speeds below a resonance speed of the gas turbine engine.

3. The bowed rotor start mitigation system as in claim 1, wherein the measured temperature is adjusted with respect to a measured ambient temperature of the gas turbine engine by subtracting the measured ambient temperature.

4. The bowed rotor start mitigation system as in claim 1, wherein the measured temperature is determined based on averaging readings from one or more temperature sensors of the gas turbine engine for a predetermined period of time when the start sequence of the gas turbine engine is initiated.

5. The bowed rotor start mitigation system as in claim 1, wherein based on determining that bowed rotor mitigation is complete, the controller is operable to monitor a vibration level while sweeping through a range of rotor speeds including a critical rotor speed and determine whether bowed rotor mitigation was successful prior to starting the gas turbine engine.

6. The bowed rotor start mitigation system as in claim 1, wherein the measured temperature is determined based on averaging data from one or more temperature sensors at station 3 of the gas turbine engine.

7. The bowed rotor start mitigation system as in claim 1, wherein the measured temperature is determined based on averaging data from one or more temperature sensors at station 4 of the gas turbine engine.

8. The bowed rotor start mitigation system as in claim 1, wherein the measured temperature is determined based on averaging data from one or more temperature sensors at station 4.5 of the gas turbine engine.

9. The bowed rotor start mitigation system as in claim 1, wherein the controller is operable to drive motoring of the gas turbine engine by oscillating the rotor speed to continuously rotate within the motoring band for the motoring time based on the measured temperature when the start sequence of the gas turbine engine is initiated and prior to determining that bowed rotor mitigation is complete.

10. A gas turbine engine system comprising:

a motoring system operable to drive rotation of the gas turbine engine;

a speed pickup;

a temperature sensor; and

an electronic engine control operable to receive a speed input from the speed pickup indicative of a rotor speed of the gas turbine engine and a measured temperature from the temperature sensor, the electronic engine control further operable to drive motoring of the gas turbine engine by controlling the motoring system to oscillate the rotor speed within a motoring band for a motoring time based on the measured temperature when a start sequence of the gas turbine engine is initiated, wherein the motoring time is associated with a bowed rotor risk parameter that is determined based on the measured temperature using a mapping function or lookup table with a higher risk resulting in a longer duration to reduce a temperature gradient within the gas turbine engine.

11. The gas turbine engine as in claim 10, wherein the motoring band comprises a range of speeds below a resonance speed of the gas turbine engine and the measured temperature is adjusted with respect to a measured ambient temperature of the gas turbine engine by subtracting the measured ambient temperature.

12. A method of bowed rotor start mitigation for a gas turbine engine, the method comprising:

receiving, by a controller, a speed input indicative of a rotor speed of the gas turbine engine;

receiving, by the controller, a measured temperature of the gas turbine engine; and

driving, by the controller, motoring of the gas turbine engine by oscillating the rotor speed within a motoring band for a motoring time based on the measured temperature when a start sequence of the gas turbine engine is initiated, wherein the motoring time is associated with a bowed rotor risk parameter that is determined based on the measured temperature using a mapping function or lookup table with a higher risk resulting in a longer duration to reduce a temperature gradient within the gas turbine engine.

13. The method as in claim 12, wherein the motoring band comprises a range of speeds below a resonance speed of the gas turbine engine.

14. The method as in claim 12, wherein the measured temperature is adjusted with respect to a measured ambient temperature of the gas turbine engine by subtracting the measured ambient temperature.

15. The method as in claim 12, wherein the measured temperature is determined based on averaging readings from one or more temperature sensors of the gas turbine engine for a predetermined period of time when the start sequence of the gas turbine engine is initiated.

16. The method as in claim 12, wherein based on determining that bowed rotor mitigation is complete, the controller is operable to monitor a vibration level while sweeping through a range of rotor speeds including a critical rotor speed and determine whether bowed rotor mitigation was successful prior to starting the gas turbine engine.

17. The method as in claim 12, wherein the measured temperature is determined based on averaging data from one or more temperature sensors at station 3 of the gas turbine engine.

18. The method as in claim 12, wherein the measured temperature is determined based on averaging data from one or more temperature sensors at station 4 of the gas turbine engine.

19. The method as in claim 12, wherein the measured temperature is determined based on averaging data from one or more temperature sensors at station 4.5 of the gas turbine engine.

20. The method of claim 12, wherein driving motoring of the gas turbine engine is performed by oscillating the rotor speed to continuously rotate within the motoring band for the motoring time based on the measured temperature when the start sequence of the gas turbine engine is initiated and prior to determining that bowed rotor mitigation is complete.