Abstract:
A method for assembling a gas turbine engine is provided. The method includes providing a vane sector and a honeycomb seal. The method further includes coupling the honeycomb seal to the vane sector utilizing a hydraulic tool.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates generally to gas turbine engines and, more particularly, to methods and apparatus for coupling honeycomb seals to gas turbine engine components.  
         [0002]     Honeycomb seals are widely used in gas turbine engine applications. For example, at least some known gas turbine engines include at least one row of rotor blades that is radially inward from a plurality of honeycomb seals within cavities formed within a surrounding stator vane assembly. At least some known honeycomb materials are installed into a gas turbine engine via a manual crimping process to fixed vane sector components, for example. During break-in engine operations, seal teeth located on a first rotatable annular member cut grooves or channels into the honeycomb seals located on a second member having a different rotational speed than that of the first member. The channels cut by the seal teeth define an operating clearance between the seal teeth and the honeycomb material, and permit the honeycomb material to substantially prevent air from flowing between the honeycomb material and the first member.  
         [0003]     During assembly of at least some known honeycomb seals, the seals are manually crimped into the fixed vane sector components using a hammer and a non-marring nylon block that impacts the honeycomb seal. More specifically, often it requires repeated blows from the hammer before the honeycomb seal is fixed in position across the length of the honeycomb seal track. However, repeated hammering across the honeycomb seal track may damage the honeycomb or the seal track, may increase the risk of hammer blow pinch, and/or may limit the useful life expectancy of the honeycomb seal.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0004]     In one aspect, a method for assembling a gas turbine engine is provided. The method includes providing a vane sector and a honeycomb seal. The method also includes coupling the honeycomb seal to the vane sector utilizing a hydraulic tool.  
         [0005]     In another aspect, a tool for assembling a gas turbine engine is provided. The tool includes a hydraulic mechanism and a tooling assembly coupled to the hydraulic mechanism. The tooling assembly is configured to crimp a honeycomb seal to a vane sector. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a schematic illustration of an exemplary gas turbine engine;  
         [0007]      FIG. 2  is a schematic end view of an exemplary stator vane assembly that may be used with the gas turbine engine shown in  FIG. 1 ;  
         [0008]      FIG. 3  is a cross-sectional view of a portion of the vane sector shown in  FIG. 2 ;  
         [0009]      FIG. 4  is a schematic view of an exemplary tool that may be used to couple a seal to the portion of the vane sector shown in  FIG. 3 ;  
         [0010]      FIG. 5 ( a ) is a front perspective view of the tooling assembly that may be used with the tool shown in  FIG. 4 ;  
         [0011]      FIG. 5 ( b ) is a rear perspective view of the tooling assembly that may be used with the tool shown in  FIG. 4 ;  
         [0012]      FIG. 5 ( c ) is a front view of the tooling assembly that may be used with the tool shown in  FIG. 4 ; and  
         [0013]      FIG. 6  is a schematic view of the tool shown in  FIG. 4  engaged with the portion of the vane sector shown in  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]      FIG. 1  is a schematic illustration of an exemplary gas turbine engine  10 . Engine  10  includes a low pressure compressor  12 , a high pressure compressor  14 , and a combustor assembly  16 . Engine  10  also includes a high pressure turbine  18 , and a low pressure turbine  20  arranged in a serial, axial flow relationship. Compressor  12  and turbine  20  are coupled by a first shaft  24 , and compressor  14  and turbine  18  are coupled by a second shaft  26 .  
         [0015]     In operation, air flows through low pressure compressor  12  from an upstream side  28  of engine  10 . Compressed air is supplied from low pressure compressor  12  to high pressure compressor  14 . Compressed air is then delivered to combustor assembly  16  where it is mixed with fuel and ignited. Combustion gases are channeled from combustor  16  to drive turbines  18  and  20 .  
         [0016]      FIG. 2  is a schematic end view of an exemplary stator vane assembly  30  that may be used with gas turbine engine  10  (shown in  FIG. 1 ). High pressure compressor  14  defines an annular flow path therethrough and includes at least one rotor disk (not shown) that includes a plurality of circumferentially-spaced, rotor blades (not shown) that extend radially outward therefrom. Stator vane assembly  30  is coupled adjacent to, and downstream from, the rotor disk. In the exemplary embodiment, stator vane assembly  30  includes six circumferentially-spaced stator vane sectors  32 , wherein each stator vane sector  32  includes sixteen circumferentially-spaced stator vanes  34 . Stator vane sectors  32  are coupled circumferentially within engine  10 . Accordingly, in the exemplary embodiment, stator vane assembly  30  includes a total of ninety six stator vanes  34  that are arranged with a substantially uniform circumferential or pitch spacing S 1  defined between each pair of adjacent stator vanes  34  within stator vane assembly  30 . In the exemplary embodiment, each stator vane sector  32  extends arcuately with a radial arc A 1  of approximately 60°. Each stator vane sector  32  also includes an inner arc  36  that is radially inward from stator vanes  34  and an outer arc  35  that is radially outward from stator vanes  34 .  
         [0017]      FIG. 3  is a cross-sectional view of a portion of vane sector  32 . Specifically,  FIG. 3  illustrates a portion of inner arc  36  including a honeycomb seal  37  inserted therein. Inner arc  36  includes a radially inward portion  38  and at least one retaining track member  40 . A radially inward surface  42  of portion  38  is coupled adjacent to vane sector stator vanes  34 . Retaining track member  40  includes a pair of opposed first portions  46  and a pair of opposed second portions  48  that each extend outwardly from, and are formed integrally with, portion  46 . In the exemplary embodiment, each first portion  46  is substantially perpendicular to inward portion  38  and each second portion  48  is substantially parallel to inward portion  38 . Accordingly retaining track member  40  and portion  38  define a track cavity  52 .  
         [0018]     Seal  37  is a honeycomb seal that is fabricated with a sealing portion  54  and a seal track  56 . In the exemplary embodiment, sealing portion  54  has a width  58  that is narrower than a width  60  of seal track  56 . Seal  37  is coupled to inner arc  36  such that at least one retaining track member  40  can be crimped against seal track  56 , as described in more detail below, to facilitate securing seal  37  within vane sector  32 . Sealing portion width  58  is narrower than an entrance width  62  of cavity  52  defined between opposed second portions  48 . Moreover, seal track width  60  is narrower than width  64  defined between opposed first portions  46 . In addition, a height  66  of seal track  56  is shorter than a corresponding height  68  of track cavity  52  as defined by second portions  48 , and as such, sealing track  56  is sized for insertion into track cavity  52 .  
         [0019]      FIG. 4  is a schematic view of an exemplary tool  200  used to couple seal  37  to vane sector  32  (shown in  FIG. 3 ), and more specifically to inner arc  36  (shown in  FIG. 3 ). FIGS.  5 ( a - c ) are each respective views of an exemplary tooling assembly  201  that may be used with tool  200 .  FIG. 5 ( a ) is a perspective front view of tooling assembly  201 ,  FIG. 5 ( b ) is a perspective rear view of tooling assembly  201 , and  FIG. 5 ( c ) is a front view of tooling assembly  201 . In one embodiment, tool  200  may be a Series PNC Clamp commercially available from by PHD, Inc., Fort Wayne, Ind. Tool  200  includes a base  202  that securely couples tool  200  to a fixture, such as a table or a wall. In an alternative embodiment, base  202  rotatably couples tool  200  to a fixture. Tool  200  also includes a body  204  that extends from base  202 . A pair of jaws  206  are hingedly secured to body  204  at a distal end  207  of tool  200 . Tooling assembly  201  couples to jaws  206  to enable tooling assembly  201  to crimp retaining track members  40  received within jaws  206 . Specifically, tooling assembly  201  includes a first portion  209  and a second portion  210 , and jaws  206  include an upper jaw  211  that is configured to couple to first portion  209  and a lower jaw  212  that is configured to couple to second portion  210 .  
         [0020]     Retaining track member second portion  48  is arcuate and is formed with a first radius R 1  and radially inward surface  42  is arcuate and is formed with a second radius R 2 . In one embodiment, a clamping surface  214  of first portion  209  is formed with a radius R 3  that is approximately one thousandth of a degree less than radius R 1  of retaining track member second portion  48 . Furthermore, a clamping surface  216  of second portion  210  is formed with a radius R 4  that is approximately one thousandth of a degree greater than radius R 2  of radially inward surface  42 .  
         [0021]     In the exemplary embodiment, a first coupling portion  220  of tooling assembly  201  is formed unitarily with tooling assembly first portion  209 , and is sized for insertion into upper jaw  211 . Similarly, a second coupling portion  222  of tooling assembly  201  is formed unitarily with tooling assembly second portion  210 , and sized for insertion into lower jaw  212 .  
         [0022]     First portion clamping surface  214  is arcuate and is formed with a radius R 3 . Radius R 3  is approximately one thousandth of a degree less than retaining track member second portion radius R 1 . Furthermore, second portion clamping surface  216  is formed with a radius R 4  that is approximately one thousandth of a degree greater than radially inward surface radius R 2 . Clamping surfaces  214  and  216  facilitate accommodating the varying radii between retaining track member second portion  48  and radially inward surface  42 . Moreover, clamping surface  216  is disposed at, and closes at, an angle θ to facilitate preventing distortion of inner arc  36 . Specifically a second portion front surface  226  is taller than a second portion rear surface  228 , such that clamping surface  216  slopes away from front surface  226  towards rear surface  228  at an angle θ.  
         [0023]     Tooling assembly second portion  210  also includes a pair of flanges  229  that extend outward from a front surface  226  of tooling assembly second portion  210 . Flanges  229  facilitate supporting vane sector  32  while inserted into tooling assembly  201 .  
         [0024]      FIG. 6  is a schematic view of tool  200  engaged with a portion of vane sector  32 . During use tooling assembly first portion  209  engages retaining track member second portion  48  and tooling assembly second portion  210  engages radially inward portion  38 . As first portion  209  is moved downward towards tooling assembly second portion  210 , retaining track member second portion  48  is crimped to an angle β defined by retaining track member first portion  46 . In one embodiment angle β is between approximately 30-60°. As second portion  48  is crimped against seal track  56 , honeycomb seal  37  is secured within vane sector  32   
         [0025]     Prior to operating tool  200 , honeycomb seal  37  is inserted into vane sector  32  such that seal track  56  is retained in track cavity  52 , and is positioned between retaining track member second portion  48  and radially inward portion  38 . A section of vane sector  32  is inserted into tool  200  such that tooling assembly first portion  209  engages retaining track member second portion  48  and tooling assembly second portion  210  engages radially inward surface  42 . Vane sector  32  is then supported by positioning radially inward portion  38  upon flanges  229 .  
         [0026]     In the exemplary embodiment, tool  200  is activated using a foot pedal  217 . In the exemplary embodiment, foot pedal  217  is a five-way two-position pedal which actuates a pneumatic valve (not shown). Foot pedal  217  enables an operator to switch tool  200  between powered closed and power open cycles. Foot pedal  217  also allows an operator to open or close jaws  206  while leaving both hands free to manipulate vane sector  32 .  
         [0027]     Using foot pedal  217 , the operator selects a first position of foot pedal  217  to operate the power close cycle of tool  200 . By depressing foot pedal  217  the user can begin crimping seal  37  to vane sector  32 . In the exemplary embodiment, a pneumatic or hydraulic differential motor (not shown), housed within body  204 , drives a piston (not shown) attached to a mechanical linkage (not shown). In an alternative embodiment, the tool may be driven by other means, including, but not limited to, an electric motor. Both the piston and the mechanical linkage are also housed within body  204 . Driving the mechanical linkage closes jaws  206  to facilitate closing tooling assembly  201  upon vane sector  32 .  
         [0028]     Specifically, tooling assembly first portion  209  engages retaining track member second portion  48  and tooling assembly second portion  210  engages radially inward portion  38 . Tooling assembly first portion  209  moves downward towards tooling assembly second portion  210 , during which time, tooling assembly  201  forces retaining track member second portion  48  into contact with seal track  56  of honeycomb seal  37 . Accordingly, seal track  56  is secured between retaining track member  40  and radially inward portion  38  to facilitate securing honeycomb seal  37  within vane sector  32 .  
         [0029]     The radii of tooling assembly first portion clamping surface  214  and tooling assembly second portion clamping surface  216  allow first portion  209  and second portion  210  to maintain substantially congruent lines of contact upon both retaining track member second portion  48  and radially inward portion  38 . Specifically, tooling assembly  201  is designed to account for the varying radii between retaining track member second portion  48  and radially inward surface  42  to facilitate preventing bending moments from being placed on vane sector  32  which would crack the brittle braze joints which hold vane sector  32  together. Tooling assembly  201  also facilitates preventing undesirable marring of vane sector  32 . Moreover, the angled closing of tooling assembly first portion  209  prevents distortion of inner arc  36 .  
         [0030]     After retaining track member  40  has been crimped upon seal track  56 , the operator uses a second position of foot pedal  217  to operate tool  200  in an open cycle. The open cycle drives the motor in an opposite direction of the powered closing cycle, causing the mechanical linkage to open jaws  206 . When jaws  206  are opened, the operator removes the first section of vane sector  32  and selects a second section of vane sector  32 , adjacent the first section, to have a seal crimped therein. The second section of vane sector  32  is inserted into tooling assembly  201  in the same fashion as the first section. Using the foot pedal the crimping process is repeated. The operator repeats these steps until the entire length of retaining track member  40  has been closed in contact with the entire length of seal track  56 . The process is then repeated on the opposite side of vane sector  32  to close the opposing side of retaining track member  40  onto seal track  56 . When both sides of retaining track member  40  have been closed onto seal track  56  along the entire length of inner arc  36 , seal  37  will be properly secured to vane sector  32 .  
         [0031]     The above-described methods and apparatus allow an operator to efficiently crimp a honeycomb seal onto a vane sector of a gas turbine engine. The efficiency of crimping is increased, in comparison to known honeycomb seal attachment means, because the need for a ball peen hammer and a non-marring block is eliminated by the present invention. As such, the likelihood of errors and the amount of physical effort that must be exerted by an operator are each facilitated to be reduced. Furthermore, the above-described tool enables a more uniform honeycomb seal to be crimped into a vane sector without abnormal stresses to the brittle brazed joints. By reducing the potential for error and decreasing the time required to crimp a vane sector, the present invention provides a more reliable and less costly alternative to known honeycomb crimping methods.  
         [0032]     As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.  
         [0033]     Although the methods and systems described herein are described in the context of crimping a honeycomb seal to the vane sector of a gas turbine engine, it is understood that the crimping methods and systems described herein are not limited to honeycomb seals or gas turbine engines. Likewise, the crimping tool components illustrated are not limited to the specific embodiments described herein, but rather, components of the crimping tool can be utilized independently and separately from other components described herein.  
         [0034]     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.