Patent Application
20090255269
1. Technical Field
The disclosure generally relates to gas turbine engines.
2. Description of the Related Art
Varying the nozzle exhaust area of a gas turbine engine can affect engine performance. By way of example, varying the nozzle exhaust area can alter propulsive efficiency, fan stability, noise output, and/or fuel consumption.
Gas turbine engine systems involving variable nozzles with sliding doors are provided. In this regard, an exemplary embodiment of a door assembly for a gas turbine engine comprises: a door configured for alignment with an exit area of a nozzle and operative to variably open and close the nozzle exit area such that gas directed along a gas path defined, at least in part, by the nozzle exit area is regulated.
An exemplary embodiment of a nozzle assembly for a gas turbine engine comprises: a nozzle defining a nozzle exit area; and a door operative to selectively increase and decrease an effective size of the nozzle exit area.
An exemplary embodiment of a gas turbine engine comprises: a compressor; a turbine operative to drive the compressor; and a nozzle assembly positioned downstream of the turbine, the nozzle assembly defining an exit area and having a door operative to move between an open position, at which the nozzle assembly exhibits a maximum exit area, and a closed position, at which the nozzle assembly exhibits a minimum exit area.
Other systems, methods, features and/or advantages of this disclosure will be or may become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features and/or advantages be included within this description and be within the scope of the present disclosure.
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Gas turbine engine systems involving variable nozzles with sliding doors are provided, several exemplary embodiments of which will be described in detail. In some embodiments, such a sliding door is moved fore and aft in a gas turbine engine to vary the nozzle exhaust area of the engine dynamically. Varying the nozzle exhaust area in a gas turbine engine can increase engine performance characteristics such as fuel efficiency.
The exhaust section 108 of gas turbine engine 100 includes nozzle assembly 10, which defines an exit area 14. In operation, gas is routed along a gas path 26, which passes through duct 16 to the nozzle assembly 10, and then out of the nozzle assembly via exit area 14. Performance of the gas turbine engine 100 can be affected by regulating gas directed along gas path 26 by influencing the gas in a vicinity of the exit area 14.
In this regard, reference is made to the perspective diagram of
The sliding door 12 is configured to be variably positioned along a range of positions between a full open position, at which the nozzle assembly 10 exhibits a maximum exit area, and a full closed position, at which the nozzle assembly 10 exhibits a minimum exit area. As the sliding door 12 is variably positioned, gas directed along gas path 26 is regulated.
In the embodiment of
By way of example, the actuator 20 can be an air motor driven direct actuated ball screw ram, direct actuated hydraulic ram, and air or hydraulic driven mechanisms. Actuator 20 may be singular or a plurality of synchronized actuators. For example, the actuator 20 includes air motor driven direct actuated ball screw rams (such as linear motion cylindrical actuators or rotary motion actuators), synchronized via flex drive cables (a commonly used actuation configuration in various commercial nacelle reverser cowlings). The actuator 20 can be located unobtrusively in an area 30 of the nozzle assembly 10 between gas path 26 and a core path 24.
In some embodiments, a nozzle assembly can also incorporate a pressurized plenum. Such a pressurized plenum can be configured to provide pressure balancing to the nozzle assembly thereby reducing actuation loads. If the loads are predicted to be reacted primarily by the tracks, a plenum may not be required. However, when a plenum is utilized (such as in association with area 30 in this embodiment), the plenum can be a direct acting plenum placed, for example, on the forward facing face of the door. Alternatively, a remote balance chamber can be utilized.
The nozzle assembly 10 also incorporates a rail 22 for the sliding door 12. The rail 22 facilitates the translation of the sliding door 12. In particular, the rail 22 provides a track on which the sliding door 12 is translated. The rail 22 also is configured to provide alignment and structural stability to the sliding door 12. In at least one embodiment, more than one rail 22 is utilized. In other embodiments, the rail 22 includes one or more bearings to facilitate a smoother translation of the sliding door 12 along the rail 22. In yet another embodiment, the tracks of the rail 22 can be embedded in the fixed structure ahead of the door 12, and/or along sides of the door, such that that door 12 is cantilevered aft and the tracks are hidden from the flowpath.
The nozzle assembly 10 also incorporates a plurality of stiffening ribs 28 to control deflection of the sliding door as the sliding door 12 is variably opened and closed. For example, as the sliding door 12 is variably closed, pressure increases within the duct 16. The plurality of stiffening ribs 28, located behind the interior wall of the duct 16, reduces deflection of the interior wall. The plurality of stiffening ribs 28 also provides structural support to the sliding door 12 as the door translates across the exit area 14 of the nozzle assembly 10.
The actuator 20 is connected to the sliding door 12 and is configured to operatively translate the sliding door 12 in both a fore and aft direction, as indicated by arrows 18, thus varying the exit area 14 of the nozzle assembly 10. In operation, the sliding door 12 is variably opened and closed, by translating in both a fore and aft direction, as indicated by arrows 18. In other embodiments, more complex motion of the sliding door can be used. Regardless of the particular motion involved, positioning of the door varies the exit area 14 of the nozzle assembly 10 and thereby affects one or more of various engine performance characteristics.
It should be emphasized that the above-described embodiments are merely possible examples of implementations set forth for a clear understanding of the principles of this disclosure. Many variations and modifications may be made to the above-described embodiments without departing substantially from the spirit and principles of the disclosure. By way of example, in some embodiments, a sliding door can be configured to alter a nozzle throat asymmetrically in order to affect yaw vectoring of the flow. In some embodiments, this can be accomplished by the use of differential actuation of multiple actuators. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the accompanying claims.
