Patent Application
20140064910
Embodiments of the present application relate generally to gas turbine engines and more particularly to systems and methods to control variable stator vanes in gas turbine engines.
During operation of a gas turbine engine using a multi-stage axial compressor, a turbine rotor is turned at high speeds by a turbine so that air is continuously induced into the compressor. The air is accelerated by rotating blades and swept rearwards onto adjacent rows of variable stator vanes. Each rotor blade/variable stator vane stage increases the pressure of the air.
In addition to translating the kinetic energy of the air into pressure, the variable stator vanes also serve to correct the deflection given to the air by the rotor blades and to present the air at the correct angle to the next stage of rotor blades. Pivoting the variable stator vanes permits the flow capacity of the compressor or turbine to be changed, thereby ensuring that the flow capacity is always at an optimum value for the particular operating conditions of the gas turbine engine. Accordingly, there is a need to control the angle of the variable stator vanes.
Some or all of the above needs and/or problems may be addressed by certain embodiments of the present application. According to one embodiment, there is disclosed a variable stator vanes control mechanism for a gas turbine engine. The control mechanism may include a moveable actuation rod in operative communication with a torque shaft such that movement of the actuation rod rotates the torque shaft. The control mechanism may also include a first unison ring in operative communication with the torque shaft such that rotation of the torque shaft drives the first unison ring. Moreover, the control mechanism may include a second unison ring in operative communication with the torque shaft such that rotation of the torque shaft drives the second unison ring.
According to another embodiment, there is disclosed a method to control variable stator vanes in a gas turbine engine. The method may include actuating a moveable actuation rod in operative communication with a torque shaft such that movement of the actuation rod rotates the torque shaft. The method may also include driving a first unison ring in operative communication with the torque shaft such that rotation of the torque shaft drives the first unison ring. Moreover, the method may include driving a second unison ring in operative communication with the torque shaft such that rotation of the torque shaft drives the second unison ring.
Further, according to another embodiment, there is disclosed a variable stator vanes control mechanism for a gas turbine engine. The gas turbine engine may include a compressor having a compressor casing. The control mechanism may include a moveable actuation rod in operative communication with a torque shaft such that movement of the actuation rod rotates the torque shaft. The control mechanism may also include a first unison ring in operative communication with the torque shaft such that rotation of the torque shaft drives the first unison ring about the compressor casing. Moreover, the control mechanism may include a second unison ring in operative communication with the torque shaft such that rotation of the torque shaft drives the second unison ring about the compressor casing.
Other embodiments, aspects, and features of the invention will become apparent to those skilled in the art from the following detailed description, the accompanying drawings, and the appended claims.
Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
Illustrative embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments are shown. The present application may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Like numbers refer to like elements throughout.
Illustrative embodiments are directed to, among other things, systems and methods to control variable stator vanes in gas turbine engines.
The gas turbine engine 10 may use natural gas, various types of syngas, and/or other types of fuels. The gas turbine engine 10 may be any one of a number of different gas turbine engines offered by General Electric Company of Schenectady, N.Y., including, but not limited to, those such as a 7 or a 9 series heavy duty gas turbine engine and the like. The gas turbine engine 10 may have different configurations and may use other types of components.
Other types of gas turbine engines also may be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment also may be used herein together.
Located externally of the casing 28 and adjacent to each set of variable stator vanes 30 are unison rings 38 extending circumferentially about the casing 28. The vane stems 34 of each set of variable stator vanes 30 are connected to the corresponding unison ring 38 by a respective lever 40. One end of the lever 40 is clamped to the end of the vane stem 34 by a bolt 42 so that there is no relative movement between the stem 34 and the lever 40. The other end of the lever 40 is connected to the unison ring 38 by a pin 44 rotatable in a bush bearing located in the unison ring 38.
The unison ring 38 is arranged so that it may be rotated about the central axis of the compressor section 12 in either direction of arrow 9. Consequently, rotation of the unison ring 38 causes rotation of each variable stator vane 30 via the levers 40 and thus enables the variable stator vanes 30 to assume required angles of incidence to the incoming air.
The variable stator vanes control mechanism 100 may also include a bell crank mechanism 114. The bell crank mechanism 114 may be in operative communication with the first unison ring 104. The bell crank mechanism 114 may also be in operative communication with a second unison ring 116 such that movement of the first unison ring 104 in the first direction 106 translates movement, by way of the bell crank mechanism 114, to the second unison ring 116 in a second direction 118 that is opposite the first direction 106 of the first unison ring 104. Rotation of the second unison ring 116 causes rotation of each variable stator vane 110 connected to the second unison ring 116 by the levers 112.
Still referring to
In operation, the movable actuator rod 102 actuates the first unison ring 104 thereby rotating the first unison ring 104 in the first direction 106 about the casing 108. As the first unison ring 104 rotates about the casing 108 in the first direction 106, it drives the first turnbuckle 122. The first turnbuckle 122 then applies a pivoting force to the pivot 120. The pivoting of the pivot 120 causes the second turnbuckle 124 to drives the second unison ring 116 thereby causing the second unison ring 116 to rotate in the second direction 118 about the casing 108. In this embodiment, the second direction 118 and the first direction 106 are opposite of each other. The rotation of the first unison ring 104 and the second unison ring 116 causes the respective variable stator vanes 110 attached to each unison ring to rotate in opposite directions due to the movement of the levers 112. Accordingly, the angle of the variable stator vanes 110 may be adjusted with the variable stator vanes control mechanism 100.
As described above, the first direction 106 and the second direction 118 are relative to each other. Accordingly, the first direction 106 and the second direction 118 may be any direction about the casing 108. Moreover, the moveable actuation rod 102 may be in operative communication with the first unison ring 104, the second unison ring 106, or the bell crank mechanism 114.
In certain embodiments, the bell crank mechanism 114 may be at least partially secured to the casing 108 of the compressor. In other embodiments, the moveable actuator rod 102 may be at least partially secured to the casing 108 of the compressor. One will appreciate, however, that the bell crank mechanism 114 and the moveable actuator rod 102 may be at least partially secured at any location on or about the gas turbine engine.
A relative movement between the first unison ring 104 and the second unison ring 116 and the angle of the variable stator vanes 110 may be adjusted by varying the dimensions of the pivot 12, the first turnbuckle 122, and the second turnbuckle 124. Moreover, the angle of the variable stator vanes 110 may be varied by varying the length of the levers 112.
In an embodiment, as depicted in
The embodiments as depicted in
Still referring to
The embodiment as depicted in
As described above, the first direction 308 and the second direction 318 are relative. The first direction 308 and the second direction 318 may be the same direction or different directions about the casing 310. For example, in embodiments where the first direction and the second direction are the same, the turnbuckles 305 and 307 may be attached on the same side of the torque shaft. Conversely, in embodiments where the first direction and the second direction are different, the turnbuckles 305 and 307 may be attached on opposite sides of the torque shaft. The first direction 308 and the second direction 318 may be any direction about the casing 310. Moreover, the moveable actuation rod 302 may be in operative communication with the first unison ring 306, the second unison ring 316, or the torque shaft 304.
In operation, the movable actuator rod 302 is attached to the casing 310 and actuates the torque shaft 304 thereby rotating the torque shaft 304. The turnbuckle 305 connects the first unison ring 306 to the torque shaft 304, and the turnbuckle 307 connects the second unison ring 316 to the torque shaft 304. As the torque shaft 304 rotates, the turnbuckles 305 and 307 drive the first unison ring 306 and the second unison ring 316 about the compressor casing 310. The rotation of the first unison ring 306 and the second unison ring 316 causes the respective variable stator vanes attached to each unison ring by the respective levers 314 to rotate. Accordingly, the angle of the variable stator vanes may be adjusted with the variable stator vanes control mechanism 300. One will appreciate that one or more additional unison rings may be in communication with the torque shaft by one or more respective turnbuckles.
In certain embodiments, the moveable actuator rod 302 may be at least partially secured to the casing 310 of the compressor. One will appreciate, however, that the moveable actuator rod 302 may be at least partially secured at any location on or about the gas turbine engine. Moreover, the torque shaft 304 may be rotatably supported about the casing 310 of the compressor by a support structure 320. The support structure 320 may be any configuration that facilitates the rotation of the torque shaft about the compressor casing 310.
The variable stator vanes control mechanism 400 may include a moveable actuation rod 402. The moveable actuation rod 402 may be attached to the casing 404 or any other location on or about the gas turbine engine. The moveable actuation rod 402 may also be attached to a gear ring 406. The gear ring 406 may be disposed about the compressor casing 404 such that the gear ring 406 rotates about the compressor casing 404 when actuated by the moveable actuation rod 402. A rub block 408 may be disposed between the casing 404 and the gear ring 406 to facilitate smooth rotation of the gear ring 406 about the casing 404.
A number of variable stator vanes 410 may be disposed on a first side 412 and a second side 414 of the gear ring 406. The variable stator vanes 410 form a first compressor stage and a second compressor stage respectively on each side of the gear ring 406. The variable stator vanes 410 may include gear stems 416. The gear stems 416 may be in operative communication with the gear ring 406.
In operation, the movable actuation rod 402 is attached to the casing 404 and actuates the gear ring 406 thereby rotating the gear ring 406 about the casing 404. The gear stems 416 of the variable stator vanes 410 are in operative communication with the gear ring 406 such that as the gear ring 406 rotates about the casing 404, the gear stems 416 of the variable stator vanes 410 are rotated. The rotation of the gear stems 416 adjusts the angle of the variable stator vanes 410.
In certain embodiments, the rotation of the variable stator vanes 410 may be controlled by the addition of gears or gear train type mechanisms operatively disposed between the gear stems and the gear ring. For example, as depicted in
One will appreciate that any number of additional gears or gear train type mechanisms may be operatively disposed between the gear ring and the gear stems to facilitate a desired rotation. Moreover, the gear ratio and the number of gear teeth may be adjusted to control the schedule between variable stator vane stages.
Although embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the disclosure is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as illustrative forms of implementing the embodiments.
