VARIABLE VANE SYSTEM FOR TURBOMACHINE WITH LINKAGE HAVING TAPERED RECEIVING APERTURE FOR UNISON RING PIN

A variable vane fluid system is disclosed with variable stator vanes and a unison actuation structure supported for movement about a longitudinal axis between a first rotational position and a second rotational position to coincidentally rotate the plurality of vanes. The unison actuation structure has a projection. The variable vane fluid system further includes an elongate linkage member having a first portion connected to a stator vane and a second portion with an aperture that receives the projection. The aperture includes an inner surface with a tapered inner surface profile to allow the projection to tilt within the aperture as the unison actuation structure rotates between the first rotational position and the second rotational position.

TECHNICAL FIELD

The present disclosure generally relates to a variable vane system, such as a variable inlet guide vane (IGV) system for a turbomachine and, more particularly, relates to a variable vane system with a linkage having a tapered receiving aperture for a unison ring pin.

BACKGROUND

Turbomachine compressors can be used in a variety of applications. For example, some compressors (e.g., axial compressors) may be included in a gas turbine engine. In many cases, compressors may include a rotor and a variable vane system. The variable vane system may include a plurality of vanes that may be selectively actuated to change fluid flow to the rotor.

The loads needed for actuating the vanes may be relatively high, requiring a high-powered and costly actuator. Also, the variable vane system may be susceptible to wear. Furthermore, manufacture of these variable vane systems may be complex, time consuming, and inconvenient.

Accordingly, it is desirable to provide an improved variable vane system, wherein the vanes are actuated efficiently and accurately. Furthermore, it is desirable to provide a more robust variable vane system that is less susceptible to wear. Additionally, it is desirable to provide a variable vane system that can be manufactured in a more efficient manner. Other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.

SUMMARY

According to various embodiments, a variable vane fluid system is disclosed for a turbomachine. The variable vane fluid system includes a support structure that defines a longitudinal axis. The variable vane fluid system also includes a plurality of variable stator vanes including a first stator vane. The plurality of variable stator vanes is supported by the support structure for rotational movement for varying fluid flow through the turbomachine. The variable vane fluid system also includes a unison actuation structure supported by the support structure for movement about the longitudinal axis between a first rotational position and a second rotational position to coincidentally rotate the plurality of vanes. The unison actuation structure has a projection. The variable vane fluid system further includes an elongate linkage member having a first portion connected to the first stator vane and a second portion with an aperture that receives the projection. The aperture includes an inner surface with a tapered inner surface profile to allow the projection to tilt within the aperture as the unison actuation structure rotates between the first rotational position and the second rotational position.

Additionally, a method of manufacturing a turbomachine is disclosed. The method includes attaching a plurality of variable stator vanes including a first stator vane to a support structure, including supporting the plurality of stator vanes with the support structure for rotational movement that varies fluid flow through the turbomachine. The method also includes attaching a unison actuation structure with a projection to the support structure, including supporting the unison actuation structure with the support structure for movement about the longitudinal axis between a first rotational position and a second rotational position. Furthermore, the method includes coupling the first stator vane to the projection with an elongate linkage member such that movement of the unison actuation structure between the first rotational position and the second rotational position coincidentally rotates the first stator vane, including attaching a first portion of the linkage member to the first stator vane and receiving the projection in an aperture at a second portion of the linkage member. The aperture includes an inner surface with a tapered inner surface profile to allow the projection to tilt within the aperture as the unison actuation structure rotates between the first rotational position and the second rotational position.

Also provided according to various embodiments is a gas turbine engine with a variable vane system. The variable vane system includes a support structure that defines a longitudinal axis. Furthermore, the variable vane system includes a plurality of variable stator vanes including a first stator vane. The plurality of variable stator vanes is supported by the support structure for rotational movement for varying fluid flow through the gas turbine engine. The variable vane system also includes a unison ring supported by the support structure for movement about the longitudinal axis between a first rotational position and a second rotational position to coincidentally rotate the plurality of stator vanes. The unison ring has a pin that projects away from the longitudinal axis. The variable vane system additionally includes an elongate linkage member with a rigid arm having a first end that is attached to the first stator vane. The elongate linkage member has a bushing that is removably attached to a second end of the arm. The bushing has an aperture that receives the pin. The aperture includes an inner surface with a tapered inner surface profile to allow the pin to tilt within the aperture as the unison ring rotates between the first rotational position and the second rotational position.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the application and uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. In addition, those skilled in the art will appreciate that embodiments of the present disclosure may be practiced in conjunction with any type of compressor, and that the axial compressor described herein is merely one exemplary embodiment of the present disclosure. It should be noted that many alternative or additional functional relationships or physical connections may be present in an embodiment of the present disclosure.

The present disclosure generally relates to a variable vane system with features that allow stator vanes to move efficiently and effectively with relatively low actuating forces.

The features reduce wear on the components as well. Furthermore, manufacture of the system can be completed quickly, efficiently, and conveniently.

In some embodiments, the variable vane system of the present disclosure may include linkages that couple stator vanes to a unison actuation structure (e.g., a unison ring). At least one linkage may include an aperture that receives a mating part. The aperture may include a tapered interior surface that allows the mating part to pivot within the aperture as the components rotate about respective axes. Furthermore, in some embodiments, the aperture may be incorporated in a replaceable bushing. The bushing may be made from a high-performance material, such as polyether ether ketone (PEEK) in some embodiments.

Thus, loads on the bushing and the mating part can be relatively low. Also, these components are less susceptible to wear. Additionally, the system may be manufactured efficiently. Furthermore, repair of the joint between the linkage and mating part is convenient, for example, because the bushings may be replaced easily.

With reference toFIGS. 1 and 2, an exemplary turbomachine, such as a gas turbine engine100, is shown that is configured to include a variable vane fluid system of the present disclosure. It should be noted that while the variable vane fluid system of the present disclosure is discussed with regard to the gas turbine engine100, the variable vane fluid system of the present disclosure can be employed with any suitable engine, such as a turbojet engine, a scramjet engine, an auxiliary power unit (APU), or other turbomachine without departing from the scope of the present disclosure.

As shown in the example ofFIG. 2, the exemplary gas turbine engine100may include a fan section102, a compressor section104, a combustion section106, a turbine section108, and an exhaust section110. The fan, combustion, turbine, and exhaust sections102,106,108,110can be substantially similar to those of a conventional gas turbine engine; therefore, the fan, combustion, turbine, and exhaust sections102,106,108,110will not be discussed in detail herein. It should also be understood thatFIGS. 1 and 2are merely illustrative and may not be necessarily drawn to scale. In addition, while the fluid moving through the engine100may be air, it should be noted that the present disclosure is not so limited. Instead, the present disclosure may apply to any turbomachine that receives any suitable fluid.

The fan section102includes a fan112mounted in a fan casing114. The fan112induces air from the surrounding environment into the engine100and passes this air toward the compressor section104.

The compressor section104includes at least one compressor and, in this example, includes a low-pressure (LP) compressor116(may also be referred to as an intermediate-pressure (IP) compressor, a booster or T-stage) and a high-pressure (HP) compressor118. The LP compressor116raises the pressure of the air directed into it from the fan112and directs the compressed air into the HP compressor118. The LP compressor116and the HP compressor118may be axi-symmetrical about a longitudinal centerline axis120. The LP compressor116and the HP compressor118are mounted in a compressor casing122(i.e., shroud).

Still referring toFIG. 2, the combustion section106of the gas turbine engine100includes a combustor124in which the high-pressure air from the HP compressor118is mixed with fuel and combusted to generate a combustion mixture of air and fuel. The combustion mixture is then directed into the turbine section108. The turbine section108includes a number of turbines disposed in axial flow series.FIG. 2depicts a high-pressure turbine126, an intermediate pressure turbine128, and a low-pressure turbine130. While three turbines are depicted, it is to be understood that any number of turbines may be included according to design specifics. For example, a propulsion gas turbine engine may comprise only a high-pressure turbine and a low-pressure turbine. The combustion mixture from the combustion section106expands through each turbine126,128,130, causing them to rotate. As the turbines126,128,130rotate, each respectively drives equipment in the gas turbine engine100via concentrically disposed spools or shafts132,134,136. The combustion mixture is then exhausted through the exhaust section110.

With reference toFIG. 3, a schematic longitudinal sectional view through a portion of the HP compressor118is shown. In this example, the HP compressor118includes an axial compressor section138and a centrifugal compressor section140. The axial compressor section138includes one or more rotors142and one or more stators144. The one or more rotors142and the one or more stators144are enclosed by the compressor casing122(FIG. 2). The axial compressor section138may also include an inlet guide vane system (IGV system)146. The centrifugal compressor section140can include an impeller148as shown.

With continued reference toFIG. 3, the axial compressor section138may include one or more compressor stages spaced in an axial direction along the longitudinal centerline axis120, with the one or more rotors142and the one or more stators144cooperating to define a stage. In one example, the axial compressor section138comprises a four-stage axial compressor section138, namely, a first stage150, a second stage152, a third stage154, and a fourth stage156. It should be noted, however, that the axial compressor section138may have any number of stages, and thus, it will be understood that the present teachings herein are not limited to an axial compressor section138having four stages.

In this example, the first stage150may include a rotor158and a stator160. The rotor158may be disposed downstream of the IGV system146and may be disposed between the IGV system146and the stator160. The second stage152may include a rotor162and a stator164. The rotor162may be disposed downstream of the stator160and may be disposed between the stator160and the stator164. The third stage154may include a rotor166and a stator168. The rotor166may be disposed downstream of the stator164and may be disposed between the stator164and the stator168. The fourth stage156may include a rotor170and a stator172. The rotor170may be disposed downstream of the stator168and may be disposed between the stator168and the stator172. Also, the stator172of the fourth stage156may be disposed upstream of the impeller148of the centrifugal compressor section140.

The IGV system146will now be discussed in detail with reference toFIGS. 4and5. The IGV system146may be selectively adjusted to vary the fluid flow to the rotor158. The IGV system146may include one or more features that reduce wear, that provide a robust connection between components, that reduce the input force necessary to adjust the vanes, and/or that facilitate manufacturing. Although these features of the present disclosure are incorporated in the IGV system146upstream of the first stage150(FIG. 3), it will be appreciated that these features may be incorporated in a variable vane system for any of the stages150,152,154,156without departing from the scope of the present disclosure.

The IGV system146may include a support structure200. The support structure200may include any number of rigid and strong structures (e.g., rings, brackets, struts, etc.) that support other components of the system146. In some embodiments, the support structure200may include an outer support ring201(FIGS. 4 and 5) and an inner support ring207(partially shown inFIG. 5). The support rings201,207may both be centered about the centerline axis120of the engine100. The support rings201,207may be fixed to the compressor casing122(FIG. 1) or other housing/support structure(s) of the engine100.

Furthermore, the IGV system146may include a plurality of variable stator vanes202, one of which is shown inFIG. 5. The plurality of vanes202may radiate about the axis120and may extend between the inner and outer support rings207,201. The ends of each vane202may be rotatably attached to the inner and outer support rings207,201. A vane stem203may project outward radially from the respective vane202and may extend radially through the outer support ring201as shown inFIG. 5. Accordingly, each vane202may be supported for rotation about a respective vane axis205. As shown inFIG. 4, the vanes202may be disposed upstream of blades of the rotor158. Accordingly, movement of the vanes202may selectively change fluid flow to the rotor158as will be discussed.

Moreover, the IGV system146may include a unison actuation structure204. In some embodiments, the unison actuation structure204may include a ring206(i.e., a unison ring). The ring206may be rigid and strong and may extend annularly about the centerline axis120. The ring206may be supported by the support structure200for rotation about the axis120between various rotational positions with respect to the axis120.

Also, the IGV system146may include a plurality of projections208. The projections208may radiate and project outward radially from an outer diameter surface of the ring206. The projections208may be spaced equally about the circumference of the ring206, and the longitudinal axis of the projections208may extend normal to the axis120. As shown inFIG. 5, at least one of the projections208may be a pin that is fixed to the ring206. In some embodiments, one or more of the projections208may be press-fit into the ring206.

The IGV system146may further include a plurality of linkages210. The linkages210may respectfully include a first portion212that is attached to one of the vane stems203. As shown inFIG. 5, the first portion212may include a fastener213(e.g., a stack up of a nut, washer(s), spacer(s), etc.) that attaches the first portion212to the end of the vane stem203projecting outwardly from the outer support ring201. The fastener213may removably attach the linkage210and the vane stem203in some embodiments such that the linkage210may be removed, repaired, and/or replaced without permanent damage to the components.

The linkages210may respectively include a second portion214that is attached to the unison actuation structure204. In some embodiments, the second portion214may be attached to respective ones of the projections208as shown inFIG. 5. Specifically, the second portion214of the linkage210may receive the respective projection208. Accordingly, as will be discussed, rotation of the ring206about the axis120may, in turn, coincidentally rotate the linkages210and vanes202about the respective vane axis205.

As will be discussed, the attachment between the second portion214and the projection208of the unison actuation structure204may be a moveable (i.e., unfixed) attachment. The projections208may be somewhat loosely received in the second portion214of the linkage210such that the projections208may tilt or otherwise move relative to the linkage210. Thus, rotation of the ring206may cause the projection208to tilt and/or otherwise move slightly relative to the second portion214of the linkage210. Accordingly, the unison actuation structure204may be robustly attached to the linkage210; however, the parts are unlikely to bind, rub, elastically deform, etc. because of the attachment between the linkages210and projections208of the unison actuation structure204.

Furthermore, the IGV system146may include an actuator209, which is illustrated schematically inFIG. 4. In some embodiments, the actuator209may be a hydraulic linear actuator. The actuator209may selectively rotate the unison actuation structure204in one or both directions about the axis120. This movement may coincidentally rotate the linkages210and vanes202about their respective axis205. The actuator209may also be operatively connected to a control system, such as a computerized control system, which controls actuation of the actuator209to thereby control the position of the vanes202. In some embodiments, the control system may selectively control the actuator209(and, thus, selectively position the vanes202) based on detected engine speed or other operating characteristics of the engine100.

Referring now toFIGS. 4-7, an exemplary linkage210will be discussed according to example embodiments. In some embodiments, the linkage210may generally include an arm216and a bushing226that is removably attached to the arm216; however, it will be appreciated that the linkage210may be a unitary (one-piece) member in other embodiments of the present disclosure.

As shown inFIG. 6, the arm216may be an elongate, flat, rigid bar. The arm216may have a substantially straight longitudinal axis extending between the first and second portions212of the linkage210. The arm216may be a stamped sheet metal part in some embodiments. The arm216may include a first side218and an opposite second side220. The first side218may face radially outboard and away from the axis120of the engine100, and the second side220may face radially inboard and toward the axis120. Also, the arm216may include a first hole222at the first portion212of the linkage210and a second hole224at the second portion214of the linkage210. The first hole222may include at least one flat internal surface and, in some embodiments, may be polygonal. For example, the first hole222may be rectangular and elongated slightly toward the second portion214. The second hole224may be a circular hole. Both the first and second holes222,224may be through-holes that extend through the thickness of the arm216between the first and second sides218,220.

The first hole222may receive and attach to the vane stem203(via the fastener213) as discussed above. The flat internal surfaces of the first hole222may mate and engage opposing flat surfaces of the vane stem203to thereby engage (i.e., rotationally lock) the vane stem203and arm216for rotation as a unit about the vane axis205. Also, because the hole222is elongated along the axis of the arm216, the arm216may be supported to slide slightly in a direction that is normal to the axis205(i.e., along the longitudinal axis of the arm216).

The bushing226may be an annular member. The bushing226may be made from a polymeric material, such as polyether ether ketone (PEEK). In some embodiments, the bushing226may be formed via a machining process (e.g., turned on a lathe). The bushing226may resemble a hollow tube with a first end228, a second end230, and an aperture269that extends along a straight axis241from the first end228to the second end230. The second end230may be flared outward so as to include an outwardly extending flange232. As shown inFIG. 7, an outer surface234of the bushing226may also include a collar236disposed approximately mid-way between the first and second ends228,230. The collar236may jut outward slightly away from the axis241and may be spaced away from the flange232along the axis241. Accordingly, an undercut region238may be defined on the outer surface234between the collar236and the flange232.

Furthermore, as shown inFIG. 7, the aperture269of the bushing226may be defined by an inner surface240. The inner surface240may extend between a first rim272of the aperture269and a second rim274of the aperture269. A width270of the aperture269(measured normal to the axis241between opposite areas of the inner surface240) may vary along the length of the aperture269. In some embodiments, the inner surface240may taper with respect to the axis241such that the width270gradually changes along the longitudinal length of the aperture269. As such, the aperture269may have a tapered profile242extending between the first rim272and the second rim274of the aperture269.

As shown inFIG. 7, the tapered profile242may have an hourglass shape. In other words, between the first and second rims272,274, the tapered profile242may include a so-called pinch area244where the width270of the aperture269is smallest. The pinch area244may be disposed approximately mid-way between the first and second rims272,274of the aperture269. Additionally, the tapered profile242may include a first taper246where the aperture269tapers outward (increases gradually in width) from the pinch area244to the first rim272. Likewise, the tapered profile242may include a second taper248where the aperture269tapers outward (increases gradually in width) from the pinch area244to the second rim274.

The width270(diameter) at the pinch area244may correspond to the diameter of the projection208of the unison actuation structure204. In some embodiments, these widths (diameters) may be substantially equal, or the pinch area244may be slightly wider.

The bushing226may be removably attached to the arm216as shown inFIGS. 6 and 7. In some embodiments, the bushing226may be pressed into the second hole224of the arm216and may project axially from the first side218and the second side220of the arm216. The arm216may be snugly received in the undercut region238and retained between the collar236and the flange232of the bushing226. The second hole224may be chamfered at both ends as shown inFIG. 7such that the bushing226is securely retained within the second hole224. The flange232may project axially and radially from the second hole224at the second side220of the arm216. Also, as shown inFIG. 7, the pinch area244may be disposed axially between the first side218and the second side220of the arm216. Also, the projection208may be received in the aperture269with the pinch area244of the bushing226encircling the projection208.

Accordingly, during operation of the engine100, the actuator209may selectively rotate the unison actuation structure204between various rotational positions about the axis120. Rotation of the unison actuation structure204coincidentally rotates the linkages210and vanes202about the respective vane axis205. Accordingly, the fluid flow to the rotor158may be selectively adjusted for enhancing operating efficiency of the engine100.

FIG. 5illustrates the IGV system146in three positions as examples. A first (intermediate) position is shown in solid lines, a second (open) position is shown in phantom, and a third (closed) position is shown in phantom as well. Because of the tapered profile242of the bushing226, the projection208is allowed to tilt freely within the aperture269. More specifically, in the first position, the axis of the projection208may be aligned with the axis241of the aperture269and both may be normal to the axis120. In the second position, the axis of the projection208may be tilted (misaligned) relative to the axis241in one direction. In the third position, the axis of the projection208may be tilted (misaligned) in the opposite direction. The bushing226may loosely grip the projection208at the pinch area244, but the first and second tapers246,248may provide sufficient clearance for the projection208to tilt within the aperture269. Because the pinch area244is disposed between the first and second sides218,220of the arm216, loads may transfer between the projection208and the arm216without creating a significant moment. Also, the arm216may remain rigid and unflexed during this movement. Furthermore, while there may be some friction between the bushing226and the projection208, these loads are relatively low and resulting wear may be corrected by removing and replacing the bushing226.

Accordingly, the IGV system146may allow for selective adjustment of the vanes202. Input loads from the actuator209may be relatively low because of the tapered profile242of the linkages210. Additionally, wear may be reduced using the IGV system146of the present disclosure. Moreover, the IGV system146may be manufactured efficiently. The IGV system146may be repaired conveniently because the bushings226may be removable and replaceable.