Variable area nozzle assisted gas turbine engine restarting
AssigneeUnited Technologies Corporation
InventorsAshok K. Jain, Michael Winter
Life of this patent
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Abstract
An example turbofan engine starting system includes a core nacelle housing a compressor and a turbine. The core nacelle is disposed within a fan nacelle. The fan nacelle includes a turbofan. A bypass flow path downstream from the turbofan is arranged between the two nacelles. A controller is programmed to manipulate the nozzle exit area to facilitate startup of the engine. In one example, manipulates the nozzle exit area using nozzles, in response to an engine shutdown condition. The nozzles open and close to adjust the nozzle exit area.
Claims18
A turbofan engine restarting system, comprising:
- a core nacelle housing a compressor and a turbine;
- a fan nacelle housing a fan section that is arranged upstream from said core nacelle;
- a bypass flow path downstream from said fan section and arranged between said core and fan nacelles, said bypass flow path including an effective nozzle exit area that defines an axis;
- a controller programmed to selectively increase and decrease said effective nozzle exit area to facilitate restart of said engine during flight in air, wherein said effective nozzle area is increased when said nozzle effective area is not a maximum effective nozzle area;
- a starter for increasing a rotational speed of said fan section;
- and
- a control device arranged to receive a command from said controller in response to an engine condition, said control device changing said effective nozzle exit area provided between said core and fan nacelles in response to said command.
A method of restarting a turbofan engine comprising the steps of:
- a) detecting a shutdown of a turbofan engine during flight in air;
- b) selectively increasing and decreasing an effective nozzle exit area from a bypass flow path within the engine in response to the shutdown during a flight in air to establish a desired condition for a startup of the engine during the flight in air, the increasing and decreasing achieved by changing a physical area of an exit nozzle, the exit nozzle provided by a turbofan nacelle surrounding a fan section and a core nacelle;
- and
- c) increasing the rotational speed of a fan section of the engine using a starter.
Dependencies are inferred from the claim text.