Abstract:
A vane seal assembly for a gas turbine engine comprises of a case including a first connector. A notch in the case adjoins the groove. A vane having a second connector mates with the first connector. A seal assembly is provided between the vane and the case to provide a sealed cavity adjoining the notch.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/833,957, which was filed on 12 Jun. 2013 and is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    This disclosure relates to a seal for a gas turbine engine, such as an industrial gas turbine engine. More particularly, the disclosure relates to a seal that, in one example application, is used between stator vanes and a transition duct. 
         [0003]    A gas turbine engine typically includes a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and a ground-based generator for industrial gas turbine engine applications. 
         [0004]    One example turbine section includes high and low pressure turbine sections. A transition duct is arranged between the high and low pressure turbine sections to communicated core flow gases. A circumferential array of vanes may be provided at forward and/or aft locations of the transition duct and are typically supported by an outer case of the engine&#39;s static structure. 
         [0005]    An outer end of the vanes may include a hook which is received within a corresponding groove in the outer case. One example outer case may include circumferentially arranged, axially extending thermal stress relief notches that adjoin the groove. Cooling fluid, such as bleed air, is typically provided through the outer case to the vanes in an area of the groove to cool the vanes. The notch may permit the cooling fluid to undesirably leak through the notch into an adjoining cavity, which reduces the efficiency of the engine. 
       SUMMARY 
       [0006]    In one exemplary embodiment, a vane seal assembly for a gas turbine engine comprises of a case including a first connector. A notch in the case adjoins the groove. A vane having a second connector mates with the first connector. A seal assembly is provided between the vane and the case to provide a sealed cavity adjoining the notch. 
         [0007]    In a further embodiment of any of the above, the first and second connectors respectively provide a groove and a hook. 
         [0008]    In a further embodiment of any of the above, the vane includes a lip. The vane seal assembly comprises a transition duct having a slot for receiving the lip. The vane supports the transition duct relative to the case. 
         [0009]    In a further embodiment of any of the above, the seal assembly is secured to the transition duct and seals against the case and the vane. 
         [0010]    In a further embodiment of any of the above, the seal assembly is secured to the transition duct by a weld. 
         [0011]    In a further embodiment of any of the above, the seal assembly includes first and second seal portions in engagement with one another. 
         [0012]    In a further embodiment of any of the above, the first portion includes a bend that provides a leg. The second portion seals against the leg. 
         [0013]    In a further embodiment of any of the above, the second seal portion includes first and second bends that provide first and second arms. The first arm seals with respect to the first seal portion. The second arm seals against the vane. 
         [0014]    In a further embodiment of any of the above, the first seal portion provides a fishmouth for receiving an end of the second seal portion. 
         [0015]    In a further embodiment of any of the above, the first seal portion is secured to the case by threaded fasteners. 
         [0016]    In a further embodiment of any of the above, the case includes a flange. The seal assembly engages the flange. 
         [0017]    In a further embodiment of any of the above, the vane includes a surface. The seal assembly engages the surface. 
         [0018]    In another exemplary embodiment, a gas turbine engine includes a compressor and turbine sections. A combustor is provided axially between the compressor and turbine sections. The turbine section includes a case having a groove. A vane includes a hook received in the groove. A seal assembly is provided between the vane and the case to provide a sealed cavity. 
         [0019]    In a further embodiment of any of the above, the first and second connectors respectively provide a groove and a hook. 
         [0020]    In a further embodiment of any of the above, the case includes a notch that adjoins the groove and is configured to provide thermal stress relief of the case. The seal assembly adjoins the notch. 
         [0021]    In a further embodiment of any of the above, the gas turbine engine comprising a cooling source configured to provide cooling fluid through the case to a cooling cavity adjacent to the sealed cavity. The seal assembly blocks flow through the notch. 
         [0022]    In a further embodiment of any of the above, the turbine section includes a transition duct supported relative to the case by the vane. The seal assembly is secured to the transition duct and seals against the case and the vane. 
         [0023]    In a further embodiment of any of the above, the seal assembly includes first and second seal portions in engagement with one another. 
         [0024]    In a further embodiment of any of the above, the second seal portion includes first and second bends providing first and second arms. The first arm seals with respect to the first seal portion. The second arm seals against the vane. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
           [0026]      FIG. 1  is a schematic view of an example industrial gas turbine engine. 
           [0027]      FIG. 2  is a schematic view of a portion of a turbine section including a transition duct arranged between high and low pressure turbine sections. 
           [0028]      FIG. 3  is an example enlarged cross-sectional view of one example seal assembly. 
           [0029]      FIG. 4  is an enlarged cross-sectional view of another example seal assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    A schematic view of an industrial gas turbine engine  10  is illustrated in  FIG. 1 . The engine  10  includes a compressor section  12  and a turbine section  14  interconnected to one another by a shaft  16 . A combustor  18  is arranged between the compressor and turbine sections  12 ,  14 . The turbine section  14  includes first and second turbines that correspond to high and low pressure turbines  20 ,  22 . 
         [0031]    A generator  24  is rotationally driven by a shaft coupled to the low pressure turbine  22 , or power turbine. The generator  24  provides electricity to a power grid  26 . It should be understood that the illustrated engine  10  is highly schematic, and may vary from the configuration illustrated. Moreover, the disclosed seal assembly may be used in commercial and military aircraft engines as well as industrial gas turbine engines. 
         [0032]    The gas turbine engine  10  is shown in more detail in the area of the turbine section in  FIG. 2 . An outer case  30  provides engine static structure and includes first and second case portions  32 ,  34 , which may correspond to high and low pressure turbine cases. The first and second case portions are secured to one another at a flanged joint, for example. In one example, the outer case  30  is provided by a circumferentially continuous, unitary structure. A high pressure turbine stage  36  of the high pressure turbine section  14  includes a circumferential array of rotatable blades  38  that seal relative to the outer case  30  at a blade outer air seal  40 , which is fixed relative to the outer case  30 . A low pressure turbine stage  42  of the low pressure turbine section  20  includes a circumferential array of rotatable blades  44 . The blades  44  seal relative to the outer case  30  at blade outer air seals  46  that are secured relative to the outer case  30 . 
         [0033]    A transition duct  48  is arranged within the outer case  30  and communicates fluid from the high pressure turbine  20  to the low pressure turbine  22 . In one example, the transition duct is provided by multiple circumferentially arranged arcuate segments. First and second circumferential arrays of vanes  50 ,  52  are mounted at forward and aft locations of the transition duct  48  in the example. 
         [0034]    A cooling source  54 , such as bleed air from the compressor section  12 , provides the cooling fluid to a cavity  56 , which supplies cooling fluid to the vanes  52 , for example. 
         [0035]    Referring to  FIG. 3 , the vanes  52  include airfoils  58  extending radially inward from a platform  60 . The vanes  52  may be configured to provide a single airfoil or may be arrange in clusters of multiple airfoils. Mating connectors support the vanes  52  on the outer case. In one example, the vanes  52  include at least one hook  62  received in a circumferential groove  64  in the outer case  30 . An outer portion of the transition duct  48  is supported relative to the outer case  30  by the vanes  52 . In one example, the vanes  52  include a lip  68  that is received in a slot  70  of the transition duct  48 . 
         [0036]    Multiple notches  66  are provided in the outer case  30  at spaced apart circumferential locations to relieve stresses due to thermal expansion and contraction of the turbine section components during engine operation. The notches  66  provide undesired fluid communication between the cavity  56  and an adjacent cavity  100 . 
         [0037]    A seal assembly  74  is provided between the outer case  30  and the vanes  52  to seal the cavity  56  from the cavity  100  and block the undesired leakage from the cavity  56  through the notch  66  to other portions of the gas turbine engine. The seal assembly  74  may be provided by arcuate segments that are interleaved with one another to seal the segments to one another. 
         [0038]    In one example, a flange  72  extends from the outer case  30 . The seal assembly  74  is provided by first and second seal portions  76 ,  78 . The second seal portion  78  is attached to the transition duct  48  by weld, rivet, or bolt. The first seal portion  76  is mounted to the flange  72  by first fastening elements  84 , which are threaded fasteners in one example. In one example, the first seal portion  76  includes first and second legs  80 ,  82  joined by a bend  81 . An end  86  of the second leg  82  is canted radially inward to facilitate assembly of the engine. 
         [0039]    The second seal portion  78  includes first and second arms  88 ,  90  secured to the transition duct  48  by a second fastening element  102 , which in one example is a weld. The first arm  88  includes a first bend  92  that biases a first end  91  into engagement with the second leg  82  of the first seal portion  76 . The second arm  90  includes a second bend  94  that biases a second end  93  into engagement with a surface  96  of the vane  52 . 
         [0040]    During assembly, the first seal portion  76  is secured to the outer case  30 . The second seal portion  78  is secured to the transition duct  48 . The transition duct  48  is inserted axially into the outer case  30  such that the second seal portion  78  engages and seals relative to the first seal portion  76 . The canted end  86  of the second leg  82  accommodates the first arm  88  as the transition duct  48  is inserted into the outer case  30 . The vane  52  is inserted axially into the outer case such that the lip  68  received in the slot  70 , and the hook  62  is received in the groove  64 . With the vane  52  mounted to the outer case  30 , the second portion  78  seals against the vane  52 . The bend  94  and having first end  91  slide on second leg  82  and canted end  86  at assembly permit sufficient compliance of the seal assembly  74  while avoiding plastic deformation of the seal assembly during assembly. 
         [0041]    Another example seal assembly  174  is shown in  FIG. 4 . The first seal portion  176  includes a third leg  104  secured to the second leg  182  by third fastening elements  106 , such as rivets, to provide a fishmouth that receives an end of the second portion  178 . The second portion  178  is attached to the transition duct  148  by weld, rivet, or bolt. The seal assembly  174  provides a seal with respect to the outer case  130 , transition duct  148  and vane  152 , as described above with respect to  FIG. 3 . 
         [0042]    The seal assembly  74  is constructed from a flexible material capable of providing the necessary deflection at the given operating temperature of that portion of the engine. The seal assembly  74  may be stamped, and includes a cross-sectional thickness in the range as required to provide proper contact at the first end  91  and the second end  93 . 
         [0043]    Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.