Method and apparatus for controlling compressor bleed airflow of a gas turbine engine using a butterfly valve assembly

A method and apparatus for controlling fluid flow is provided. The valve assembly includes a valve body including a longitudinal axis and a radially inner internal flow passage extending axially between an inlet opening and an outlet opening, a disk selectively positionable to modulate a flow of working fluid through the flow passage, and a radially outer external surface. The valve assembly further includes a first actuator positioned radially outboard of the external surface, a second actuator positioned radially outboard of the external surface, and a first linkage including a first actuator end configured to couple to the first actuator, a second actuator end configured to couple to the second actuator, and a rod end configured to couple to the disk, wherein an actuating force applied from each actuator to each respective actuator end is combined through the first linkage to the rod end.

BACKGROUND OF THE INVENTION

This invention relates generally to gas turbine engines and more particularly, to a method and apparatus used to regulate fluid flow for a gas turbine engine.

At least some known gas turbine engines include an engine casing that extends circumferentially around a compressor, and a turbine including a rotor assembly and a stator assembly. Within some engines, a plurality of ducting and valves coupled to an exterior surface of the casing are used to channel fluid flow from one area of the engine for use within another area of the engine. For example, such ducting and valves may form a portion of an environmental control system (ECS).

Typically, valve assemblies are used to control fluid flow that is at a high temperature and/or high pressure. Such valve assemblies include a substantially cylindrical valve body that is coupled between adjacent sections of ducting. The valve body includes a valve sealing mechanism that is selectively positionable to control fluid flow through the valve. More specifically, at least some known valves include a single piston/cylinder arrangement that is positioned external to the valve body and is coupled to the valve sealing mechanism to provide the motive force necessary to selectively position the valve sealing mechanism.

Because the piston/cylinder arrangement is offset from the main valve body, a center of gravity of the valve assembly is typically displaced a distance from a centerline axis of the valve body. Such an eccentric center of gravity may induce bending stresses into the valve assembly, adjoining tubing, and supporting brackets during engine operation. Depending on the application, the physical size and weight of the piston/cylinder arrangement may also present difficulties during the duct routing phase of the engine design.

A concentric valve is one way to address such difficulties. The concentric valve as described in U.S. Pat. Nos. 6,775,990 and 6,986,257 features an actuation piston that surrounds the flowbody of the valve, hence the name. This piston is sized so that the inner and outer diameters of the piston form an actuation area that fluid pressure works against. This area is typically set to achieve a force margin of at least 3:1, after accounting for all resistive forces. The fluid pressure level acting on the piston is usually set by the system architecture. In some cases, the actuation fluid (fuel) pressure is reasonably low, at about 130 psid for example. For other cases, the fluid pressure is much higher, at up to about 900 psid.

The pressure level and other geometrical constraints can create a situation where it is not practical to have an actual concentric piston surrounding the flowbody. Cases of extremely high pressure may necessitate a piston with a wall thickness of only 0.030″ to achieve a 3:1 force margin. Such a constraint may not be practical as there is not enough space for guide seal glands, and it is not desirable to place the glands in the housing walls. Additionally, to handle the high burst pressure conditions (3000 psia in some cases) the actuator housing walls have to be sized to resist the hoop stresses. While it is possible to make a concentric valve for such applications there is a penalty incurred in the form of weight and packaging volume.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a valve assembly includes a valve body including a longitudinal axis and a radially inner internal flow passage extending axially between an inlet opening and an outlet opening, a disk selectively positionable to modulate a flow of working fluid through the flow passage, and a radially outer external surface. The valve assembly further includes a first actuator positioned radially outboard of the external surface, a second actuator positioned radially outboard of the external surface, and a first linkage including a first actuator end configured to couple to the first actuator, a second actuator end configured to couple to the second actuator, and a rod end configured to couple to the disk, wherein an actuating force applied from each actuator to each respective actuator end is combined through the first linkage to the rod end.

In another embodiment, a method of controlling fluid flow includes channeling a flow of fluid through a body of a valve, the body including a longitudinal axis, modulating the flow of fluid through body of the valve using a disk member, and controlling the position of the disk member using a plurality of actuators, each coupled to the disk member, wherein a center of mass of the body of the valve and the plurality of actuators is substantially concentric with the longitudinal axis.

In yet another embodiment, a gas turbine engine system includes a compressor, a valve assembly coupled in flow communication with the compressor wherein the valve assembly is configured to channel a fluid from the compressor to an outlet pipe. The valve assembly includes a valve body extending along a longitudinal axis and a radially inner internal flow passage extending axially between an inlet opening and an outlet opening, a disk selectively positionable to modulate a flow of working fluid through the flow passage, and a radially outer external surface. The valve assembly further includes a plurality of actuators positioned radially outboard of the external surface, and a first linkage including a first actuator end coupled to the first actuator, a second actuator end coupled to the second actuator, and a rod end coupled to the disk, wherein an actuating force applied from each actuator to each respective actuator end is combined through the first linkage to the rod end and wherein a center of mass of the body of the valve and the plurality of actuators is substantially concentric with the longitudinal axis.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description illustrates embodiments of the invention by way of example and not by way of limitation. It is contemplated that the invention has general application to assembly and process control embodiments of fluid flow control in industrial, commercial, and residential applications.

FIG. 1is a side view of a gas turbine engine assembly10that may be used with embodiments of the present invention. In the exemplary embodiment, gas turbine engine assembly10includes a plurality of ducting12coupled together by a plurality of valve assemblies14. Gas turbine engine assembly10includes a high-pressure compressor assembly16, a combustor18, and a turbine assembly20. In one embodiment, high-pressure compressor assembly16is a high-pressure compressor. Gas turbine engine assembly10also includes a low-pressure turbine (not shown) and a fan assembly (not shown). In one embodiment, gas turbine engine assembly10is a CF34 engine commercially available from General Electric Company, Cincinnati, Ohio.

In the exemplary embodiment, ducting12and valve assemblies14form a portion of an engine build up (EBU)30. More specifically, ducting12and valve assemblies14facilitate channeling and controlling, respectively, fluid flow at a high temperature, and/or at a high pressure, from one area of gas turbine engine assembly10for use in another area. For example, in one embodiment, fluid flowing through ducting12and valve assemblies14has an operating temperature that is greater than about 1000° F. and/or an operating pressure of greater than about 300 psi.

In the exemplary embodiment, ducting12includes a Y-duct32that facilitates splitting EBU30into a pair of inlet duct assemblies34and36that are coupled to an engine casing40by a plurality of mounting bracket assemblies42. More specifically, inlet duct assemblies34and36are coupled in flow communication to high-pressure compressor assembly16for routing bleed air from high-pressure compressor assembly16for use in other areas, such as an environmental control system.

FIG. 2is an exploded view of valve assembly14(shown inFIG. 1) in accordance with an exemplary embodiment of the present invention. In the exemplary embodiment, valve assembly14includes a valve body200having a longitudinal axis202and a radially inner internal flow passage204extending axially between an inlet opening206and an outlet opening208, a disk210is selectively positionable to modulate a flow of fluid such as, but not limited to, compressor bleed air through flow passage204. Valve body200also includes a radially outer external surface212. Valve assembly14includes a first actuator214and a second actuator216each positioned radially outboard of external surface212. In one embodiment, first actuator214and second actuator216are positioned 180° apart circumferentially with respect to longitudinal axis202. In various other embodiments, first actuator214and second actuator216are positioned at other than 180° apart circumferentially with respect to longitudinal axis202. In yet other embodiments, additional actuators, such as, but not limited to, a third (not shown) and a fourth actuator (not shown) may be used. In another embodiment, first actuator214and second actuator216are spaced circumferentially about valve body200such that a centerline of mass217passing through valve assembly14is substantially concentric with longitudinal axis202.

Valve assembly14includes a first linkage218comprising a first actuator end220configured to couple to first actuator214, a second actuator end222configured to couple to second actuator216, and a rod end224configured to couple to disk210. In one embodiment, first linkage218is wishbone-shaped. In the exemplary embodiment, rod end224is configured to couple to disk210using a tie rod226, a crank arm227, and a shaft228. An actuating force applied from each actuator214,216to each respective actuator end220,222is combined through first linkage218to rod end224. In the exemplary embodiment, actuators214and216comprises a piston230,231, a piston rod232,233, a rod bushing234,235, and a cylinder236,237forming piston-type actuators. The pistons of actuators214and216are positioned in cylinders236and237, respectively, by a pressure of a working fluid such as, but not limited to, liquid fuel acting on the pistons. In the exemplary embodiment, the working fluid is coupled to actuators214and216such that the pistons work in parallel and impart substantially equal force to rod end224through first linkage218. In an alternate embodiment, at least one of first actuator214and second actuator216comprises an electric drive.

During operation, a movement of pistons230and231acting on actuators ends220and222respectively causes first linkage218to rotate about an axis of rotation292extending though pins244and246. Pivot links242and246allow axis of rotation292to translate transversely to movement of actuators214and216, thereby maintaining pure translation of actuator ends220,222. The rotation of first linkage218causes rod end224to move in an open direction253toward inlet opening206to open valve assembly14or to move in a close direction254toward outlet opening208to close valve assembly14. A fluid such as, but not limited to, liquid fuel being introduced into cylinders236and237at substantially equal pressures forces piston rods232and233to move within cylinders236and237respectively. Resilient bushings234and235include glands for o-rings for sealing purposes, and internal dynamic cup seals to seal pressure with respect to the piston rods. In various embodiments, for fail open or fail closed operation, springs may be positioned to move piston rods232and233within cylinders236and237respectively to position disk210in the open or closed position upon loss of fuel pressure.

FIG. 3is a cutaway view of valve assembly14(shown inFIG. 1) in accordance with an exemplary embodiment of the present invention. In the exemplary embodiment, valve assembly14is shown in an open position. To position disk210in the open position, a pressurized fluid is introduced into cylinders236and237above pistons230and231, which causes pistons230and231to move towards outlet opening208imparting a force onto actuator ends220and222of first linkage218. First linkage218pivots about pins244and246moving rod end224towards inlet opening206, which rotates shaft228in a counterclockwise direction300through tie rod226and crank arm227pinned to tie rod226.

FIG. 4is a cutaway view of valve assembly14(shown inFIG. 1) in accordance with an exemplary embodiment of the present invention. In the exemplary embodiment, valve assembly14is shown in a closed position. To position disk210in the closed position, a pressurized fluid is introduced into cylinders236and237beneath pistons230and231, which causes pistons230and231to move towards inlet opening206imparting a force onto actuator ends220and222of first linkage218. First linkage pivots about pins244and246moving rod end224towards outlet opening208, which rotates shaft228in a clockwise direction400through tie rod226and crank arm227pinned to tie rod226.

Embodiments of the invention use two or more piston actuators positioned at 180 degrees spacing from one another. Using two relatively small pistons offered a 35% weight savings over a similar design with a concentric piston, largely a result of smaller actuator cavity volumes resisting burst pressure. Use of two pistons with a “Wishbone” intermediate linkage to join the output forces from each piston provides similar power to move disk210in a smaller lighter valve assembly14.

These pistons need not be positioned at exactly 180 degrees, because independent pistons mitigate the cocking likelihood of a concentric piston without balanced output. The pistons could in fact be located next to one another noting that as the pistons are placed closer to one another (from 180 degrees), ancillary hardware such as an LVDT and servo valve are moved closer to the pistons, increasing a center of mass eccentricity. The mass concentric valve assembly14includes two separate pistons driving a wishbone linkage. This configuration may be used when actuation pressure is extremely high, rendering a concentric piston impractical. The two separate pistons promote a more centered valve mass than can be achieved with a legacy offset actuator type valve, and promote a more generally compact valve.

The above-described embodiments of a method and apparatus for controlling fluid flow provides a cost-effective and reliable means reducing the size and weight of a valve assembly in applications where a relatively high actuation pressure is needed. More specifically, the method and apparatus described herein facilitate evenly distributed force from a plurality of actuators spaced circumferentially about the valve assembly. As a result, the method and apparatus described herein facilitate controlling fluid flow in a cost-effective and reliable manner.