METHOD AND SYSTEM FOR STARTING UP AN AIRCRAFT TURBOMACHINE

• US 20140373553A1
• Filed: 06/25/2014
• Published: 12/25/2014
• Est. Priority Date: 06/25/2013
• Status: Active Grant

• Current Assignee: Airbus Operations SAS (Airbus SE)
• Original Assignee: Airbus Operations SL (Airbus SE), Airbus Operations (European Aeronautic Defence and Space Company EADS NV)
• Inventors: Zaccaria, Patrick, Chareyre, Philippe, Fernandez-Lopez, Pio, Casado-Montero, Carlos
• Granted Patent: US 10,125,690 B2
• Time in Patent Office: Days
• US Class Current: 60/778
• 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 7/277 the starter being a separate turbine
• CPC Class Codes: F05D 2220/50 for auxiliary power units (APU's)
• CPC Class Codes: F05D 2260/85 Starting
• CPC Class Codes: F05D 2260/96 Preventing, counteracting or reducing vibration or noise
• CPC Class Codes: F05D 2270/114 by limiting mechanical stresses
• CPC Class Codes: F05D 2270/304 Spool rotational speed

Abstract

A start-up system including a control system controlling a partial opening of an air intake valve of a start-up turbine during a first phase of the start-up. The start-up turbine is capable of turning a rotor of the turbomachine for the purpose of the start-up, so as to prevent the rotor from encountering critical frequencies of the turbomachine

Claims

1. A method for starting up an aircraft turbomachine with the aid of a start-up system comprising at least:

one ventilation source able to produce a flow of air and provided with a compressor fed by an air intake circuit regulated by at least one inlet valve, said inlet valve being able to be controlled; and

at least one start-up turbine fed by said ventilation source via a pneumatic connection, said start-up turbine being able to produce, when subjected to a flow of air, a mechanical force making it possible to turn a rotor of the turbomachine for the purpose of the start-up,

wherein said method comprises at least two successive steps;

a first step, during which said inlet valve is open partially, such that the ventilation source transmits a limited flow of air to said start-up turbine, this limited flow of air being such that said start-up turbine turns said rotor at a speed of rotation that is lower than a critical speed; and

a second step, during which said inlet valve is completely open, such that the ventilation source transmits a maximum flow of air to said start-up turbine.

2. The method as claimed in claim 1, wherein said first step is implemented for a predetermined period, at the end of which said second step is implemented.

3. The method as claimed in claim 1, further comprising:

a step of determining a period referred to as a plateau period, prior to said first step, and

wherein said first step is implemented for a period equal to said plateau period.

4. The method as claimed in claim 3, wherein said step of determining a plateau period comprises:

measuring the value of at least one of the following parameters;

the off time of the turbomachine,

an external pressure and

an external temperature, and

calculating the plateau period with the aid of said measured value.

5. The method as claimed in claim 1, wherein a monitoring is performed during said first step in order to verify whether at least one condition representative of the absence of a deformation of thermomechanical origin at the turbomachine is met, and said second step is implemented as soon as said condition is met.

6. The method as claimed in claim 5, wherein said monitoring comprises measuring the value of at least one parameter, comparing this measured value with a predetermined value, and deducing therefrom, as the case may be, a detection of said condition representative of the absence of a deformation.

7. The method as claimed in claim 6, wherein the measured parameter is a vibration over the body of the turbomachine.

8. The method as claimed in claim 1, wherein said inlet valve is brought into and held in a partial open position during said first step, said position having a predetermined valve angle of aperture.

9. The method as claimed in claim 1, further comprising a step of determining a valve angle of aperture, prior to said first step, and wherein said inlet valve is brought into and held during said first step in an open position having this valve angle of aperture.

10. A system for starting up an aircraft turbomachine, said system comprising:

a ventilation source able to produce a flow of air and provided with a compressor fed by an air intake circuit regulated by at least one inlet valve, said inlet valve being able to be controlled;

at least one start-up turbine fed by said ventilation source via a pneumatic connection, said start-up turbine being able to produce, when subjected to a flow of air, a mechanical force making it possible to turn a rotor of the turbomachine for the purpose of the start-up; and

a control system capable of controlling at least said inlet valve,

wherein said control system is configured to control a partial opening of said inlet valve during a first phase of the start-up, such that the ventilation source then transmits a limited flow of air to said start-up turbine, this limited flow of air being such that said start-up turbine turns said rotor at a speed of rotation that is lower than a critical speed, and to control a complete opening of said inlet valve during a second phase of the start-up, such that the ventilation source then transmits a maximum flow of air to said start-up turbine.

11. The system as claimed in claim 10, further comprising at least one first sensor for measuring a first parameter making it possible to provide a piece of information concerning a deformation of thermomechanical origin prior to the rotation of the rotor, the measured value of said first parameter being provided to the control system so as to determine a plateau period.

12. The system as claimed in claim 10, further comprising at least one second sensor for measuring a second parameter making it possible to provide a piece of information concerning a deformation of thermomechanical origin during the rotation of the rotor, the measured value of said second parameter being provided to the control system so as to determine a condition for triggering a switchover.

13. The system as claimed in claim 10, wherein said control system comprises a first and a second control unit connected together, wherein said first control unit is configured to receive data, carry out processing operations and transmit a piece of control information to said second control unit, and wherein said second control unit is configured to control the opening of said inlet valve based on the piece of control information received from said first control unit.