METHOD OF STARTING A GAS TURBINE ENGINE

• US 20160348588A1
• Filed: 01/28/2015
• Published: 12/01/2016
• Est. Priority Date: 01/28/2015
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Linz, Mark Edward, Garrett, Joseph Daniel III, Broda, Joseph Roger, Gillingham, Thomas Earl, Graziano, Kevin Richard, Hon, Robert Charles, Kirchmayer, Kenneth, Kiracofe, Daniel Roy, Lehmann, Andrew Todd, McCambrige, Michael Scott, Swager, Thomas Charles, Ross, Steven Alan, Ansari, Amid, Steen, Tod Robert
• Granted Patent: US 10,502,139 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F01D 19/02 dependent on temperature of component parts, e.g. of turbine-casing
• 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 7/12 Cooling of plants of component parts, see the relevant subclasses, e.g. F01D; cooling of engines in general F01P
• 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 2260/85 Starting
• CPC Class Codes: F05D 2270/042 by keeping it below damagingly high values
• CPC Class Codes: F05D 2270/304 Spool rotational speed
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A method of starting a gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor.

Claims

1. A method of starting a gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor, the method comprising:

an acceleration phase where the rotational speed of the rotor is increased toward a combustion speed to force air through the engine;

a bowed-rotor cooling phase, during the acceleration phase, where the rotational speed of the rotor is maintained below a bowed-rotor threshold speed until a non-bowed rotor condition is satisfied, wherein the air forced through the gas turbine engine cools the rotor; and

a combustion phase, after the bowed-rotor cooling phase and upon reaching the combustion speed, where fuel is supplied to the gas turbine engine and ignition is turned on.

2. The method of claim 1 further comprising an idle phase, after the combustion phase, where the rotational speed of the rotor is accelerated to an idle speed.

3. The method of claim 1 wherein the acceleration phase comprises externally rotating the rotor.

4. The method of claim 3 wherein externally rotating the rotor comprises using a turning motor system operably coupled to the rotor.

5. The method of claim 1 wherein the bowed-rotor threshold speed comprises a non-contact speed below which a bowed-rotor does not contact the casing.

6. The method of claim 5 wherein the non-contact speed is less than a natural frequency of the turbine engine.

7. The method of claim 1 wherein the non-bowed-rotor condition comprises maintaining the rotational speed of the rotor below the bowed-rotor threshold speed for a predetermined time.

8. The method of claim 7 wherein the predetermined time is less than 90 seconds.

9. The method of claim 8 wherein maintaining the rotational speed of the rotor below the threshold speed comprises maintaining the rotational speed of the rotor at a substantially constant speed.

10. The method of claim 9 wherein the constant speed is less than a natural frequency of the turbine engine.

11. The method of claim 1 further comprising a dwell phase, during the bowed-rotor cooling phase, where the rotational speed of the rotor is maintained at a substantially constant speed below the threshold speed to maintain the rotational speed of the rotor below the threshold speed.

12. The method of claim 11 wherein the constant speed is less than a natural frequency of the turbine engine.

13. The method of claim 1 wherein the non-bowed-rotor condition comprises a rotational imbalance of the rotor.

14. The method of claim 13 further comprising sensing the rotational imbalance of the rotor and determining the rotational imbalance is less than a rotational imbalance threshold to satisfy the non-bowed-rotor condition.

15. A method of starting a gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor, the method comprising:

an acceleration phase where the rotational speed of the rotor is increased toward a combustion speed to force air through the engine;

a bowed-rotor cooling phase, during the acceleration phase, where the rotational speed of the rotor is maintained below a non-contact speed below which a bowed-rotor does not contact the casing, wherein the air forced through the gas turbine engine cools the rotor; and

a combustion phase, after the bowed-rotor cooling phase and upon reaching the combustion speed, where fuel is supplied to the gas turbine engine and ignition is turned on.

16. The method of claim 15 wherein the rotational speed of the rotor is maintained below the non-contact speed for a predetermined time.

17. A method of starting a gas turbine engine having a rotor comprising at least a shaft mounted compressor and turbine, with a casing surrounding the rotor, the method comprising:

an acceleration phase where the rotational speed of the rotor is increased toward a combustion speed to force air through the engine;

a combustion phase, during the during the acceleration phase, where fuel is supplied to the gas turbine engine and ignition is turned on;

a bowed-rotor condition monitoring phase, during the acceleration phase, where the rotor is monitored for a bowed-rotor condition; and

a bowed-rotor cooling phase, during the acceleration phase, where upon the presence of a bowed-rotor condition, the rotational speed of the rotor is maintained below a non-contact speed below which a bowed-rotor does not contact the casing, to force air through gas turbine engine to cool the rotor.

18. The method of claim 17 wherein the rotational speed of the rotor is maintained below the non-contact speed for a predetermined time.

19. The method of claim 18 wherein maintaining the rotational speed of the rotor below the non-contact speed comprises maintaining the rotational speed of the rotor at a substantially constant speed.

20. The method of claim 19 further comprising an idle phase, after the combustion phase, where the rotational speed of the rotor is accelerated to an idle speed from the combustion speed.