Method and apparatus for windmill starts in gas turbine engines
AssigneeGeneral Electric Company
InventorBarton H. Snow
Life of this patent
Estimating the term…
Abstract
A hydraulic pump and drive system is interconnected between the fan and compressor rotor of a turbofan engine such that the windmill speed of the core rotor can be boosted to a speed sufficient to allow a significantly increased in-flight start envelope by selectively extracting power from the windmilling fan prior to relight of the engine. Control logic is included to decouple the motor and pump whenever the engine is in the operating speed region and to selectively couple the fan-driven hydraulic pump to auxiliary machinery such as the nozzle actuators to obtain a dual-purpose function from the pump.
Claims18
An improved air-start system for a turbofan engine of the type having compressor rotor and fan assemblies independently driven by separate turbine means wherein the improvement comprises first drive means selectively connectible between the fan and the compressor rotor such that during periods of in-flight windmilling the fan can be made to impart rotary motion to the compressor to accelerate it to a speed sufficient to accommodate an air start.
An improved turbomachine of the type having first and second independently driven compressors rotatably mounted on an axis, with the first compressor adapted to discharge air to a combustor and the second compressor adapted to bypass at least a portion of its discharge flow around the first compressor, wherein the improvement comprises:
- a. power generation means for deriving energy from the second compressor during selective periods in which it is rotating;
- and
- b. motor means for selectively applying said derived energy to rotate said first compressor to a speed sufficient to allow a windmill start.
An improved turbofan engine of the type having a compressor and a fan adapted to bypass a portion of the airflow around the compressor during engine operation and separate turbine means for drives of the compressor and fan, wherein the improvement comprises:
- a. power generation means connected to said fan to derive energy therefrom during selective periods in which it is rotated;
- b. motor means to be selectively driven by said derived energy during predetermined periods of operation;
- and
- c. drive means connecting said motor means to said compressor to rotate it to sufficient speed so as to allow a windmill start of the engine.
A method of starting a turbofan engine of the type having a compressor and a fan adapted to bypass a portion of the airflow around the compressor during engine operation and separate turbine means for driving the compressor and fan, comprising
- a. connecting a power generation means to said fan to derive energy therefrom during selective periods in which it is rotating;
- b. selectively connecting a motor means to said power generation means to derive energy therefrom during predetermined periods of operation;
- and
- c. connecting said motor means to said compressor to rotate it to a speed sufficient to allow a windmill start of the engine.
Dependencies are inferred from the claim text.