WIEBE DAVID J (US)
US20140367925A1 | 2014-12-18 | |||
US20050082768A1 | 2005-04-21 | |||
DE102013205031A1 | 2014-09-25 |
CLAIMS What is claimed is: 1. A flexible seal (10) for at least one component (28) of a turbine engine comprising: a seal frame (12) comprising a first end (36) and a second end (38) joined by a first surface (32) and a second surface (34) extending in a longitudinal direction; and a plurality of flexible sealing arms (26) each comprising a base (40) on one end attached to at least one of the first surface (32) and the second surface (34) of the seal frame (12), an extended body length, and a tip (42) on an opposite end, wherein the plurality of flexible sealing arms (26) extend out from at least one of the first surface (32) and the second surface (34) of the seal frame (12) and elastically flex during installation into a seal slot (16). 2. The flexible seal (10) according to claim 1 , wherein the plurality of sealing arms (26) initially extend substantially in a perpendicular direction from the surface of the seal frame (12). 3. The flexible seal (10) according to claim 1 , wherein the plurality of sealing arms (26) initially extend at an acute angle from the surface of the seal frame (12). 4. The flexible seal (10) according to any of claims 1 -3, wherein the plurality of flexible sealing arms (26) are attached to one of the first surface and second surface, and the other surface comprises a riffle feature. 5. The flexible seal (10) according to claim 1, wherein the seal frame is substantially straight along the length and/or width of the seal frame. 6. The flexible seal (10) according to any of claim 1 , wherein the seal frame length and/or width comprises an alternating partem. 7. The flexible seal (10) according to claim 5, wherein the seal frame length and/or width comprises a faceted alternating pattern. 8. The flexible seal (10) according to claim 5, wherein the seal frame length and/or width comprises a smooth contoured alternating pattern. 9. The flexible seal (10) according to claim 1, wherein the seal frame is flexible. 10. The flexible seal (10) according to any of claims 1-9, further comprising a non-binding feature attached to the tip (42) of each of the plurality of sealing arms (26). 1 1. The flexible seal (10) according to any of claims 1-10, wherein the flexible seal (10) length, width, and/or thickness is variable in the seal slot (16) along an inserted direction. 12. The flexible seal (10) according to any of claims 1-1 1, wherein the plurality of flexible sealing arms (26) are angled with an acute angle facing opposite from the direction of insertion. |
BACKGROUND 1. Field
[0001] The present invention relates to gas turbine engines, and more specifically to a flexible seal for a turbine.
2. Description of the Related Art
[0002] In an axial flow industrial gas turbine engine, hot compressed gas is produced. The hot gas flow is passed through a turbine and expands to produce mechanical work used to drive an electric generator for power production. The turbine generally includes multiple stages of stator vanes and rotor blades to convert the energy from the hot gas flow into mechanical energy that drives the rotor shaft of the engine.
[0003] A combustion system receives air from a compressor and raises it to a high energy level by mixing in fuel and burning the mixture, after which products of the combustor are expanded through the turbine.
[0004] Gas turbines are becoming larger, more efficient, and more robust. Large blades and vanes are being utilized, especially in the hot section of the engine system. In view of high pressure ratios and high engine firing temperatures implemented in modern engines, certain components, such as airfoils, e.g., stationary vanes and rotating blades within the turbine section, must be cooled with cooling fluid, such as air discharged from a compressor in the compressor section, to prevent overheating of the components. When large amounts of cooling occur, however, reduction in efficiency and increases in leakages occur.
[0005] Current sealing technology uses riffle seals such as is shown in Figure 1 in order to attempt to minimize leakage. These seals are relatively thick and therefore are very stiff which then requires tight tolerances within seal slots and are therefore difficult to install. Installation of inner diameter region turbine vane riffle seals is particularly difficult due to the tolerance stack-up between the component seal slots.
SUMMARY
[0006] In one aspect of the present invention, a flexible seal for at least one component of a turbine engine comprising: a seal frame comprising a first end and a second end joined by a first surface and a second surface extending in a longitudinal direction; and a plurality of flexible sealing arms each comprising a base on one end attached to at least one of the first surface and the second surface of the seal frame, an extended length, and a tip on an opposite end, wherein the plurality of flexible sealing arms extend out from at least one of the first surface and the second surface of the seal frame and elastically flex during installation into a seal slot.
[0007] These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS [0008] The invention is shown in more detail by help of figures. The figures show preferred configurations and do not limit the scope of the invention.
[0009] FIG 1 is a side view of a riffle seal in prior art;
[0010] FIG 2 is a side view of a flexible seal in a seal slot in an exemplary embodiment of the invention; [0011] FIG 3 is a side view of a flexible seal in a seal slot in an exemplary embodiment of the invention;
[0012] FIG 4 is a side view of a flexible seal in a seal slot in an exemplary embodiment of the invention;
[0013] FIG 5 is a side view of a flexible seal in a seal slot in an exemplary embodiment of the invention; [0014] FIG 6 is a side view of a flexible seal in a seal slot in an exemplary embodiment of the invention;
[0015] FIG 7 is a side view of a flexible seal in a seal slot in an exemplary embodiment of the invention; [0016] FIG 8 is a side view of a flexible seal in a seal slot in an exemplary embodiment of the invention;
[0017] FIG 9 is a perspective view of a flexible seal in a seal slot in an exemplary embodiment of the invention;
[0018] FIG 10 is a cross-section view of a length of the flexible seal shown in FIG 9 in an exemplary embodiment of the invention;
[0019] FIG 11 is a cross-section view of a length of the flexible seal shown in FIG 9 in an exemplary embodiment of the invention; and
[0020] FIG 12 is a side view of a flexible seal showing another embodiment of the invention. DETAILED DESCRIPTION
[0021] In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, and not by way of limitation, a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention.
[0022] Broadly, an embodiment of the present invention provides a flexible seal for at least one component of a turbine engine includes a seal frame with a first end and a second end joined by a first surface and a second surface extending in a longitudinal direction. A plurality of flexible sealing arms, each comprising a base on one end, attach to at least one of the first surface and the second surface of the seal frame. The plurality of flexible sealing arms also includes an extended length and a tip on an opposite end. The plurality of flexible sealing arms extends out from at least one of the first surface and the second surface of the seal frame and elastically flex during installation into a seal slot. [0023] A gas turbine engine may comprise a compressor section, a combustor and a turbine section. The compressor section compresses ambient air. The combustor combines the compressed air with a fuel and ignites the mixture creating combustion products comprising hot gases that form a working fluid. The working fluid travels to the turbine section. Within the turbine section are circumferential rows of vanes and blades, the blades being coupled to a rotor. Each pair of rows of vanes and blades forms a stage in the turbine section. The turbine section comprises a turbine casing, which houses the vanes, blades and rotor. A blade of a gas turbine receives high temperature gases from a combustion system in order to produce mechanical work of a shaft rotation. [0024] Seals are used throughout the engine and turbine assembly. In the figures listed, a component of the assembly is shown with a flexible seal. The flexible seal may be introduced in between blades, vanes, or other components in order to help with sealing leakage flows between blades, vanes and other components. A phenomena that occurs once the assembly is at a certain rotational speed, is that there is radial growth of the airfoil as well as an untwisting at operating conditions. During this process the leakage flow between adjacent vane and blade surfaces needs to be limited. A seal, in this case, provides a sealing function for the components.
[0025] An increase in contact with all components is desirable. A reduction in component cooling and leakage is desirable. Embodiments of the present invention provide a seal with a plurality of flexible arms to replace the traditional riffle seal. The flexible seal, as will be discussed in detail below, will provide improved contact between components providing increased sealing features.
[0026] As is shown in Figures 2 through 9 and 12, a flexible seal 10 is shown being inserted. The schematics in Figures 2 through 12 show the basic concepts for the flexible seal 10. A component 28 that sees fluid often may need a seal of some sort to limit the leakage across the component 28. The component 28 may be vane or other such component that see fluid and that is a part of the turbine engine. A seal slot 16 is created on the component 28 so that a seal may be inserted. Figures 2 through 9 and 12 show the flexible seal 10 being inserted into the seal slot 16 of the component 28. The flexible seal 10 includes a seal frame 12. The seal frame 12 is the base portion of the flexible seal 10. The seal frame 12 includes a first end 36 and a second end 38. Each end is joined by a first surface 32 and a second surface 34 that extends in a longitudinal direction.
[0027] The flexible seal 10 also includes a plurality of flexible sealing arms 26. Each of the plurality of flexible sealing arms 26 are individual pieces of flexible plates or thin sheets that may bend when inserted into the seal slot. The plurality of flexible sealing arms 26 are attached to the seal frame 12. Figures 7 through 12 show flexible seal 10 embodiments with the plurality of flexible sealing arms 26 along only one surface of the seal frame 12. The plurality of flexible sealing arms 26 may act as springs that push the seal frame 12 against a top of seal glands of adjacent vanes or other such components 28 in certain embodiments. In other embodiments the plurality of flexible sealing arms 26 may push against a bottom of seal glands of adjacent vanes or other such components 28. The plurality of flexible sealing arms 26 are deflected as the plurality of flexible sealing arms 26 are inserted and the plurality of flexible sealing arms 26 exert a spring force to keep the seal frame 12 engaged against the sealing surfaces of the vanes or other such component. The vanes or other components can shift relative to one another during engine transient operation causing the sealing surfaces to be misaligned. The spring force may still push the seal frame 12 up against the sealing surfaces of the seal slot 16. Embodiments with the plurality of flexible sealing arms 26 along both surfaces of the seal frame 12, such as shown in Figures 2 through 6, provide spring force in directions that force the flexible seal 10 to push up against the sealing surfaces of the seal slot 16 and push down against the sealing surfaces of the seal slot 16.
[0028] Each of the plurality of flexible sealing arms 26 includes a base 40 on one end and a tip 42 of an opposite end along an extended body length. The base 40 of each of the plurality of flexible sealing arms 26 may be attached to at least one of the first surface 32 and the second surface 34 of the seal frame 12. The tip 42 of each of the plurality of flexible sealing arms 26 may come in contact with walls of the seal slot 16. The extended length of the plurality of sealing arms 26 may have a length extending greater than the allowable space in the seal slot 16 minus the seal frame 12. This additional length of the plurality of flexible sealing arms 26 over the space within the seal slot 16 creates a situation that the plurality of flexible sealing arms 26 need to flex or bend in order to enter and stay within the seal slot 16. The plurality of flexible sealing arms 26 elastically flex during installation into the seal slot 16 and while in use within the seal slot 16. The elastic bending allows for the plurality of flexible sealing arms 26 to conform to the seal slot 16 geometry which may reduce the tight tolerances required with a riffle seal alone and also maintain practical constant contact with the seal slot 16 walls. The plurality of flexible sealing arms 26 have more contact with the walls of the seal slot 16 that can reduce leakage between adjacent components 28. The plurality of flexible sealing arms 26 spacing may be defined by the depth of the seal slot 16 and the desired number of flexible sealing arm 26 contacts. Figures 2-8 show the plurality of flexible sealing arms 26 in a configuration prior to engagement 14 and a configuration after engagement 22 with the seal slot 16. In certain embodiments, the plurality of flexible sealing arms 26 configuration prior to engagement 14 may be substantially in a perpendicular direction from the attached surface of the seal frame 12. In other embodiments, the plurality of flexible sealing arms 26 configuration prior to engagement 14 may be tilted or curved in an acute angle from the surface of the seal frame 12 as is shown in Figure 3. The Figures 2-8 show one half of a seal slot 16 with the other half of the seal slot 16 being a mirror image. Figures 9 and 12 show two halves of the seal slot 16. [0029] Figures 2 through 6 show the plurality of flexible sealing arms 26 attached to both the first surface 32 and the second surface 34 of the seal frame 12. Figures 7 through 12 show the plurality of flexible sealing arms 26 attached to one of the first surface or the second surface of the seal frame 12. Any addition or style of flexible sealing arm 26 may be for either embodiment. As is shown in Figure 12, at least one flexible sealing arm 26 may be attached to each half for a collective plurality of flexible sealing arms 26 along the seal frame 12.
[0030] Figure 2 shows one embodiment of the present invention where the plurality of flexible sealing arms 26 is along both the first surface 32 and the second surface 34 of the seal frame 12. The plurality of flexible sealing arms 26 are in a configuration prior to engagement 14 and a configuration after engagement 22 with the seal slot 16. The flexible seal 10 may be inserted in the direction as shown by arrow D or inserted in the direction into the page as shown in a longitudinal direction.
[0031] The plurality of flexible sealing arms 26 and the seal frame 12 may have one of several different shapes in order to fit an application. The plurality of flexible sealing arms 26 may have a predominately rectangular shape and extend outward from the seal frame 23 in a substantially direction perpendicular from the seal frame 12 as is shown in Figure 2.
[0032] A concern may be the plurality of seal arm 26 thicknesses required to keep the bending stress elastic due to the short flexible sealing arm 26 length. An option is to increase the plurality of flexible sealing arm 26 lengths such as is shown in Figure 3. Figure 3 shows an embodiment where the plurality of flexible sealing arms 26 extend out form the seal frame 12 at an acute angle approximately between 0° and 90°. The plurality of flexible sealing arms 26 along one half of the seal frame 12 may be angled in one direction and the plurality of flexible sealing arms 26 along the another half of the seal frame 12 may be angled in the opposite direction to provide the best contact within the seal slot 16 for both sides of the flexible seal 10 and the component 28. The plurality of flexible sealing arms 26 may have an acute angle facing opposite from the direction of insertion. The left portion of Figure 3 would be inserted in to the other half of the seal slot 16 of the component 28 (not shown).
[0033] In certain embodiments, the length and/or width of the seal frame 12 may include an alternating pattem. The alternating pattem may be faceted, smooth contoured, or the like. The alternating pattem seal frame 12 may be used to be able to increase the plurality of flexible sealing arm length. The embodiment illustrated in Figure 4 shows a seal frame 12 that has a rectangular sinusoidal wave shape. This seal frame 12 shape allows for the length of the plurality of flexible sealing arms 26 to increase with an alternating pattern of the seal frame 12. This embodiment and the embodiment shown in Figure 5 with sinusoidal wave shape of the seal frame 12 allows for the length of the plurality of flexible sealing arms 26 to effectively double in span while providing the benefits of the flexible seal. Figure 5 shows a length of the seal frame 12 with an alternating pattern with the longer plurality of flexible sealing arms 26.
[0034] In certain embodiments, the tip 42 of each of the plurality of flexible sealing arms 26 may each include a non-binding feature 24 such as a round body or the like. The non-binding feature 24 may allow for each of the plurality of flexible sealing arms 26 to more easily slide against the seal slot 16 walls with installation as well as while in service as is shown in Figure 6. The non-binding feature 24 may be attached to any of the embodiments as described above or shown in the Figures. [0035] In certain embodiments, the seal frame 12 is flexible as well. A flexible seal frame 12 may allow for the misalignment of mate-face seal slots 16 between components 28. The combination of a flexible seal frame 12 and a plurality of flexible sealing arms 26 may allow for a further increase in the seal slot 16 dimensional tolerances. [0036] In certain embodiments, any of the previously mentioned embodiments may be converted to a one-sided flexible seal 10 as shown in Figures 7 and 8 or the two sided flexible seal 10 as shown in Figures 2 through 6. The plurality of sealing arms 26 may be attached to just the first surface 32 or just the second surface 34. These configurations are still an improvement over the current technology since these embodiments may be able to provide improved sealing function along the side of the flexible seal 10 that includes the plurality of flexible sealing arms 26. Figure 7 shows an embodiment where the plurality of flexible sealing arms 26 is along one surface of the seal frame 12. The opposite surface of the seal frame 12 may include a chamfer along a lead portion 20 of the seal frame 12. The chamfer of the lead portion 20 of the seal frame 12 may allow for an easier installation of the flexible seal 10 while maintaining the seal. In Figure 8, an addition of a riffle seal feature along the surface that does not have the plurality of flexible sealing arms 26 along the seal frame 12 may be one embodiment of the flexible seal 10.
[0037] As is shown in Figure 9 compared to the other Figures, the plurality of flexible sealing arms 26 may run in different directions. In Figure 9, each of the plurality of flexible sealing arms 26 runs along the width of the seal frame 12. In Figures 2-8 and 12, each of the plurality of flexible sealing arms 26 run along the length of the seal frame 12. Each of these configurations may be used for the various embodiments that are described above and below. [0038] The flexible seal 10 provides a seal with the plurality of flexible sealing arms 26 that may elastically flex during installation to better match the contour of the seal slot 16 in the component 28. The plurality of flexible sealing arms 26 are in contact with the component seal slot 16 at all times thereby providing the best possible seal. [0039] The size and shape of each flexible sealing arm 26 may be determined by mechanical and aerodynamic requirements such as the size of the seal slot 16. The plurality of flexible sealing arms 26 is shown with several different shapes throughout the Figures listed, however, the plurality of flexible sealing arms 26 can be any shape that may be required for the seal slot 16 geometry and sealing characteristics. [0040] In all embodiments, component 28 to component 28 contact is maintained for all operating speeds. There is no need for special tools in order to properly set and assemble each flexible seal 10 in place for proper contact.
[0041] The flexible seal 10 may have the ability to manage variation in seal slot 16 machining tolerances, surface finish, and component-to-component positioning. The seal slot 16 machining tolerances need not be small for the flexible seal 10 to fit within the seal slot 16. The plurality of flexible sealing arms 26 may be capable of managing the pathway and positional tolerances of the seal slot 16.
[0042] Optimization may occur with proper testing of the turbine. A flexible seal may provide multiple methods to seal between components during operation. The assembly of the engine may improve. Increasing seal slot dimensional tolerances may lower part costs and overall costs of the equipment. The flexible seal may also reduce seal slot wear over time.
[0043] The manufacturing of a flexible seal 10 may include options such as tack welding, welding or machining of the flexible seal arms 26 as shown in Figure 10. Figure 11 shows the flexible seal 10 with the plurality of flexible sealing arms 26 integral to the seal frame 12. The plurality of flexible sealing arms 26 may each be made from a flat piece of sheet metal or the like. The plurality of flexible sealing arms 26 may each be attached to the seal frame 12 or integral to the seal frame 12.
[0044] One advantage to manufacturing the flexible seal 10 with one side of plurality of flexible sealing arms 26 is that the plurality of flexible sealing arms 26 may be protected from the hot flow path gas by inserting the flexible seal 10 with the plurality of flexible sealing arms 26 away from the flow path. The separation may prevent the plurality of flexible sealing arms 26 from being overheated and losing their spring rate.
[0045] The plurality of flexible sealing arm 26 elastic thicknesses may be a function of flexible sealing arm 26 lengths, interference with the seal slot 16 and a flexible sealing arm 26 elastic stress limits. [0046] In certain embodiments, the seal slot 16 may be larger than current designs so that a thicker plurality of flexible sealing arms 26 may be used. The flexible seal 10 may not be reusable after disassembly. By being able to install the flexible seal 10 with increased seal slot 16 dimensional tolerances, part costs may be lowered. Further, the assembly of the engine may be easier with the increase in dimensional tolerances.
[0047] In between each component 28 may define a seal slot 16, having a slot length and a slot width between each component 28. The flexible seal 10 may have a variable length, a variable thickness, and/or a variable width in the seal slot 16 along an inserted direction. The flexible seal 10 may have a variable tangential camber within the seal slot 16. The plurality of flexible sealing arms 26 may each be of different length, a different width or different thickness along the seal slot 16 depending on the shape of the components 28. The flexible seal 10 thickness, flexible seal 10 length, and flexible seal 10 width are within the seal slot 16 width and seal slot 16 length as defined by the space between the components 28 as is shown in Figure 9. [0048] Installation of the flexible seal 10 into the seal slot 16 starts with the forward movement into the seal slot 16 of the flexible seal 10. In certain embodiments, the flexible seal 10 is moved in the direction of installation D. Typically, the last flexible seal 10 installed may be in a direction that is into the page as is shown in Figure 2. The flexible seal 10 is still moved in the direction of installation, however, due to constraints, the direction is perpendicular to the installation of other flexible seals 10. In certain embodiments, the first end 36 or second end 38 is then moved forward into an opening of the seal slot 16. As the flexible seal 10 continues to move into the seal slot 16, the plurality of flexible sealing arms 26 start to make contact with walls of the seal slot 16. The plurality of flexible sealing arms 26, in order to maintain contact with the walls of the seal slot 16, start to bend or flex. The positioning of the plurality of flexible sealing arms 26 allows for continuous contact because the plurality of flexible sealing arms 26 are bent or flexed in a position that forces the plurality of flexible sealing arms 26 against the wall of the seal slot 16, thereby maintaining contact.
[0049] In certain embodiments, as mentioned above, the flexible seal 10 is installed in a perpendicular direction. The flexible seal 10 is positioned the same within the seal slot 16, however, the entry is from a perpendicular direction from the direction D, a direction that is into the page as shown in Figure 2. The first end 36 and the second end 38 are moved forward into the opening of the seal slot 16 making contact at the same time. As the flexible seal 10 continues to move into the seal slot 16, the plurality of flexible sealing arms 26 start to make contact with walls of the seal slot 16. The plurality of flexible sealing arms 26, in order to maintain contact with the walls of the seal slot 16, start to bend or flex. The positioning of the plurality of flexible sealing arms 26 allows for continuous contact because the plurality of flexible sealing arms 26 are bent or flexed in a position that forces the plurality of flexible sealing arms 26 against the wall of the seal slot 16, thereby maintaining contact.
[0050] While specific embodiments have been described in detail, those with ordinary skill in the art will appreciate that various modifications and alternative to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims, and any and all equivalents thereof.