Abstract:
A seal assembly for a gas turbine engine including a seal member and an interstage seal ring including an axially forward member coupled to a first radially inward surface of a first disk and an axially aft member coupled to a second radially inward surface of a second disk, wherein the seal ring is configured to move in an axial direction while the upstream and downstream arms are coupled to the first and second disk respectively.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to gas turbine engines, and more specifically to seal assemblies used with gas turbine engine rotor assemblies. 
         [0002]    At least some known gas turbine engines include a core engine having, in serial flow arrangement, a fan assembly and a high pressure compressor, which compress airflow, entering the engine. A combustor ignites a fuel-air mixture, which is then channeled towards low and high pressure turbines that each include a plurality of rotor blades that extract rotational energy from airflow exiting the combustor. The high pressure compressor is coupled by a shaft to the high pressure turbine. 
         [0003]    Generally, high pressure turbines include a first stage coupled to a second stage disk by a bolted connection. More specifically, the rotor shaft extends between a last stage of the multi-staged compressor and the web portions of the turbine first stage disk. The first and second stage turbine disks are isolated by a forward faceplate that is coupled to a forward face of the first stage disk, and an aft seal that is coupled to a rearward face of the second stage disk web. An interstage seal assembly extends between the first and second stage disks to facilitate sealing flow around a second stage turbine nozzle. 
         [0004]    Commonly, interstage seal assemblies include an interstage seal and a separate blade retainer. The interstage seal is coupled to the first and second stage disks with a plurality of bolts. The blade retainer includes a split ring that is coupled to an axisymmetric hook assembly extending from the turbine stage disk. However, because the seal assemblies are complex, such interstage seal assemblies may be difficult to assemble. To facilitate reducing the assembly time and costs of such seal assemblies, other known interstage seal assemblies include an integrally-formed interstage seal and blade retainer. However, these seal assemblies while cheaper and easier to assemble, do not allow for inspection of the rotor sub-assemblies after assembly and prior to final location of the interstage seal. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    In one aspect, a seal assembly for a gas turbine engine includes a seal member and an interstage seal ring including an axially forward member coupled to a first radially inward surface of a first disk and an axially aft member coupled to a second radially inward surface of a second disk, wherein the seal ring is configured to move in an axial direction while the upstream and downstream arms are coupled to the first and second disk respectively. 
         [0006]    In another aspect, a method for assembling a seal assembly for a gas turbine engine rotor assembly includes coupling a seal ring to a first disk such that an upstream arm of the seal ring engages a first radially inward surface of the first disk and coupling the seal ring to a second disk such that a downstream arm of the seal ring engages a second radially inward surface of the second disk, wherein the seal ring is configured to move in an axial direction while the upstream and downstream arms are coupled to the first and second disk, respectively. 
         [0007]    In a further aspect, a gas turbine engine includes a fan and combustor in serial flow communication and a rotor assembly comprising, a first disk, a second disk, and a seal assembly extending between the first disk and the second disk. The seal assembly includes a seal member and an interstage seal ring, the interstage seal ring includes, a forward member coupled to a radially inward surface of the first disk and an aft member coupled to a radially inward surface of the second disk wherein the seal ring is configured to move in an axial direction while the upstream and downstream arms are coupled to the first and second disk. respectively. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0008]      FIGS. 1-4  show exemplary embodiments of the method and apparatus described above. 
           [0009]      FIG. 1  is a schematic illustration of a gas turbine engine; 
           [0010]      FIG. 2  is an enlarged partial cross-sectional view of a portion of the gas turbine engine shown in  FIG. 1 ; 
           [0011]      FIG. 3  is an enlarged partial cross-sectional view of a portion of the gas turbine engine shown in  FIG. 1  which shows the seal ring assembled and slid forward; and 
           [0012]      FIG. 4  is an enlarged partial cross-sectional view portion of the gas turbine engine shown in  FIG. 2  which shows the seal ring assembled and the retainer cutout. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]      FIG. 1  is a schematic illustration of an exemplary gas turbine engine  100 . Engine  100  includes a compressor assembly  102  and a combustor assembly  104 . Engine  100  also includes a turbine  108  and a common compressor/turbine shaft  110  (sometimes referred to as a rotor  110 ). 
         [0014]    In operation, air flows through compressor assembly  102  such that compressed air is supplied to combustor assembly  104 . Fuel is channeled to a combustion region and/or zone (not shown) that is defined within combustor assembly  104  wherein the fuel is mixed with the air and ignited. Combustion gases generated are channeled to turbine  108  wherein gas stream thermal energy is converted to mechanical rotational energy. Turbine  108  is rotatably coupled to shaft  110 . It should also be appreciated that the term “fluid” as used herein includes any medium or material that flows, including, but not limited to, gas and air. 
         [0015]      FIG. 2  is an enlarged partial cross-sectional view of a portion of gas turbine engine  100 . Specifically,  FIG. 2  illustrates an enlarged partial cross-sectional view of turbine  108 . Turbine  108  includes a first stage disk  202  and a second stage disk  204 . 
         [0016]    An interstage seal assembly  215  extends axially between turbine first and second disks  202  and  204 . More specifically, seal assembly  215  includes a seal member  201 , a seal ring  205 , and a retainer  203 . In one embodiment, seal ring  205  is generally cylindrical and includes a mid portion  227 , a first seal assembly surface  228 , and a second seal assembly surface  229 . However, in other embodiments, seal ring  205  may be an assembly of parts coupled together. Additionally, although in the exemplary embodiment the seal ring  205  comprises a cylindrical cross-section seal ring  205  is not limited to a cylindrical cross-section and for example, could have a catenary cross-section. Seal assembly surfaces  228  and  229  extend axially forward and aft, respectively from mid portion  227  to provide a contact area between seal ring  205  and first and second stage disks  202  and  204 . Seal assembly surfaces  228  and  229  are configured to create interference or rabbetted fits between first stage disk surface  230  and second disk surface  231  respectively. In various other embodiments, other fastener or attachment means may be used. In the exemplary embodiment the seal ring  205  includes a male rabbeted fit configured to engage a female rabbet on at least one of the first disk  202  and the second disk  204 . Mid portion  227  includes a plurality of seal teeth  213  which engage with seal member  201 . 
         [0017]      FIG. 3  is an enlarged view of a portion of the gas turbine engine shown in  FIG. 1 . More specifically,  FIG. 3  illustrates a positioning of seal ring  205  during assembly. During assembly, a spacer  209  is coupled to an aft edge  232  of first disk  202 . Then seal ring  205  is cooled to a substantially cooler temperature than first disk  202 . This temperature difference allows assembly surface  228  to slideably engage a radially interior surface  230  of first disk  202 . While still cooled, seal ring  205  is slid forward. This allows spacer  209  to be coupled to assembly surface  233  of second disk  204 . Next, seal ring  205  is again cooled, to a substantially lower temperature than both first disk  202  and second disk  204  and slid aft so that assembly surface  231  engages seal assembly surface  229  and seal ring  205  is axially restrained from further aft movement by surface  211  on second disk  202 . Finally, a retainer  203  may be coupled to second disk  204  at cutout  240  to restrain the axially forward movement of seal ring  205 . In the exemplary embodiment retainer  203  is a pin. In other embodiments retainer  203  could use any other means of attachment, such as, but not limited to bolts, wire retention, and bucket retention 
         [0018]      FIG. 4  is an enlarged partial view of  FIG. 2  illustrating seal ring  205  after installation. After installation, seal ring  205  may be easily relocated to allow inspection of surfaces  232  and  233 . In another embodiment, seal ring  205  may be relocated to allow assembly and disassembly of parts that are inaccessible when seal ring  205  is in the installed position. First, retainer  203 , if used, is removed. Then seal ring  205  is cooled to a substantially lower temperature than first and second disks.  202  and  204 . After cooling, seal ring  205  may be slid forward to allow inspection of surfaces  232  and  233 . 
         [0019]    Exemplary embodiments of rotor assemblies are described above in detail. The rotor assemblies are not limited to the specific embodiments described herein, but rather, components of each assembly may be utilized independently and separately from other components described herein. For example, each interstage seal assembly component can also be used in combination with other interstage seal assembly components and with other rotor assemblies. 
         [0020]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.