Apparatus and method of operating a gas turbine engine at start-up

• US 8,132,398 B2
• Filed: 03/24/2008
• Issued: 03/13/2012
• Est. Priority Date: 04/17/2007
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Wang, Yi, Rees, Paul David
• Primary Examiner(s): Gartenberg, Ehud
• Assistant Examiner(s): DWIVEDI, VIKANSHA S
• Application Number:
  US12/053,739
• Publication Number:
  US 20080250792A1
• Time in Patent Office: 1,450 Days
• Field of Search: 60/390.8, 607/72, 60/392.81, 607/36, 137/563, 137334-341
• US Class Current: 60/39.281
• CPC Class Codes: F02C 7/14 of fluids in the plant , e.g. lubricant or fuel F02C7/185 takes precedence
• CPC Class Codes: F02C 7/224 Heating fuel before feeding to the burner
• CPC Class Codes: F02C 7/275 Mechanical drives
• CPC Class Codes: F02C 7/32 Arrangement, mounting, or driving, of auxiliaries
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A method of operating a gas turbine engine having a turbine and a compressor connected via a shaft, a main fuel supply line for supplying fuel to a combustor that is positioned to release expanding hot gases to the turbine, the engine further including a starter/generator connected to the shaft via a gearbox assembly, the method is characterised the step of during engine start up fuel is circulated in a re-circulating fuel circuit positioned on the main fuel supply line and which has a first fuel/oil heat exchanger, for cooling the oil, and a fuel accumulator.

Claims

1. A gas turbine engine comprising:

a turbine;

a compressor connected via a shaft to said turbine;

a main fuel supply line for supplying fuel;

a combustor for receiving said fuel that is positioned to release expanding hot gases to the turbine, a first fuel and oil heat exchanger associated with an engine starter/generator that is connected to the shaft via a gearbox assembly;

the engine is characterised by a re-circulating fuel circuit positioned on the main fuel supply line and that has a second fuel/oil heat exchanger and a fuel accumulator, the re-circulating fuel circuit thereby cooling the oil in the starter/generator via the first fuel and oil heat exchanger.

2. A gas turbine engine as claimed in claim 1 wherein the second fuel/oil heat exchanger is fluidly connected to an engine oil circuit.

3. A gas turbine engine as claimed in claim 1 wherein the first fuel/oil heater exchanger is fluidly connected to the starter/generator.

4. A gas turbine engine as claimed in claim 1 wherein the circuit comprises a fuel filter.

5. A gas turbine engine as claimed in claim 4 wherein fuel filter is positioned between the second fuel/oil heat exchanger and the combustor.

6. A gas turbine engine as claimed in claim 1 wherein the circuit comprises a shut off valve that is provided to stop fuel return flow during normal engine running.

7. A method of operating a gas turbine engine having a turbine and a compressor connected via a shaft, a main fuel supply line for supplying fuel to a combustor that is positioned to release expanding hot gases to the turbine, the engine further having a starter/generator connected to the shaft via a gearbox assembly, a first fuel/oil heat exchanger for cooling the oil in the starter/generator oil circuit, and a fuel accumulator, the method comprising the steps of:

initiating engine start-up;

circulating fuel in a re-circulating fuel circuit positioned on the main fuel supply line.

8. A method of operating a gas turbine engine as claimed in claim 7 wherein a further step comprises supplying the cooled fuel to the starter/generator for cooling.