Patent Publication Number: US-9416673-B2

Title: Hybrid inner air seal for gas turbine engines

Description:
BACKGROUND OF THE INVENTION 
     This application relates to an inner air seal for use with a vane in a gas turbine engine. 
     Gas turbine engines are known, and typically include a compressor compressing air and delivering it into a combustion section. The air is mixed with fuel in the combustion section and ignited. Products of this combustion pass downstream over a turbine section, driving turbine rotors to rotate. 
     In the turbine section, the control of gas flow is important to achieve efficient operation. One feature of the turbine section is that there are stages of turbine rotors carrying turbine blades, and intermediate static vanes between the stages. It is desirable to prevent or limit the flow of gas through radially inner locations at the vanes. 
     Thus, the turbine blades have typically been provided with so-called knife edge seals that extend toward a seal carried by the vane. 
     In one type of seal, a generally continuous blade seal extends circumferentially beyond discrete vane bodies. This type of seal must be mounted to allow radial adjustment between the seal and the several vane bodies. 
     Another type of seal is segmented and fixed to each of the individual vane bodies. 
     During some periods of operation, the continuous vane seals may provide better sealing, however, under other periods of operation, the segmented seals will provide better sealing. 
     SUMMARY OF THE INVENTION 
     In a featured embodiment, a turbine section includes at least a first and second turbine rotor each carrying turbine blades. The rotors each have at least one rotating seal at a radially inner location. A vane section is formed of a plurality of circumferentially spaced vane components. A first seal is fixed to the platform, and has a seal material positioned to be adjacent the at least one rotating seal from the first rotor, and positioned in one axial direction relative to the first seal. A second seal extends circumferentially beyond at least a plurality of the vane components, and has a seal material positioned to be adjacent at least one rotating seal from the second rotor and on an opposed side from the first rotor. 
     In another embodiment, the second seal is circumferentially continuous. 
     In an embodiment according to the previous embodiment, the second seal is connected to the platforms of the plurality of vane components, but is radially movable relative to the platforms. 
     In another embodiment according to the prior embodiments, each of the plurality of circumferentially spaced vane components includes a plurality of vane members. 
     In another embodiment according to the prior embodiments, the first and second seals include a material mounted onto a seal mount, and the material is more abradable than the material forming the mount. 
     In an embodiment according to the prior embodiment, a first arm is fixed to the platform and extends radially inwardly in an opposed direction from the airfoil. The first arm extends to a seal mount for the first seal, and a second arm extends radially inwardly from the platform, and includes a connection to connect the second seal, and allow radial movement. 
     In another embodiment according to the prior embodiments, at least the second seal is a non-contact seal. 
     In another featured embodiment, a vane component includes a vane having an airfoil extending radially outwardly of a platform. A first seal is fixed to the platform, and has a seal material positioned to be adjacent at least one rotating seal which is positioned in one axial direction relative to the first seal when the vane component is positioned in a turbine section. A second seal extends circumferentially beyond the vane component, and has seal material positioned to be adjacent at least one rotating seal when the vane component is positioned in a turbine section. 
     In another embodiment, the second seal is circumferentially continuous. 
     In an embodiment according to the previous embodiment, the second seal is connected to the platforms of the plurality of vane components, but is radially movable relative to the platforms. 
     In another embodiment according to the prior embodiments, each of the plurality of circumferentially spaced vane components includes a plurality of vane members. 
     In another embodiment according to the prior embodiments, the first and second seals include a material mounted onto a seal mount, and the material is more abradable than the material forming the mount. 
     In an embodiment according to the prior embodiment, a first arm is fixed to the platform and extends radially inwardly in an opposed direction from the airfoil. The first arm extends to a seal mount for the first seal, and a second arm extends radially inwardly from the platform, and includes a connection to connect the second seal, and allow radial movement. 
     In an embodiment according to the prior embodiment, at least the second seal is a non-contact seal. 
     In another featured embodiment, a vane component has an airfoil extending radially outwardly of a platform. A first seal is fixed to the platform, and has a seal material positioned to be adjacent at least one rotating seal from a first rotor positioned in one axial direction relative to the first seal when the vane component is positioned in a turbine section. A second seal extends circumferentially beyond the vane component, and has a seal material positioned to be adjacent at least one rotating seal of a second rotor when the vane component is positioned in a turbine section and on an opposed side from the first rotor. The second seal is circumferentially continuous and connected to the platform of the vane component, but is radially movable relative to the platform. The first and second seal include a material mounted onto a seal mount, and the material is more abradable than a material forming the mount. A first arm is fixed to the platform and extends radially inwardly in an opposed direction from the airfoil, and with the first arm extending to the seal mount for the first seal. A second arm extends radially inwardly from the platform and the second arm includes a connection to the mount of the second seal that allows the radial movement. 
     These and other features of the present invention may be best understood from the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic gas turbine engine. 
         FIG. 2  shows an inventive arrangement. 
         FIG. 3  is a view taken generally at 90° to the  FIG. 2  view. 
         FIG. 4  shows an alternate embodiment of a seal. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a general gas turbine engine  10 , such as a turbofan gas turbine engine, circumferentially disposed about an engine centerline A. The engine  10  includes a fan  18 , a compressor  12 , a combustion section  14  and turbine section  16 . As is well known in the art, air compressed in the compressor  12  is mixed with fuel which is burned in the combustion section  14  and expanded across a turbine section  16 . The turbine section  16  includes rotors  17  that rotate in response to the expansion, driving compressor rotors  19  and fan  18 . The turbine rotors  17  carry blades  40 . Fixed vanes  42  are positioned intermediate rows of blades. This structure is shown somewhat schematically in  FIG. 1 . While one example gas turbine engine is illustrated, it should be understood this invention extends to any other type gas turbine engine for any application. 
       FIG. 2  shows a vane  42  positioned adjacent to a turbine blade  40 . As known, both vane  42  and turbine blade  40  have airfoils extending as shown in partial view in  FIG. 2 . The blade  40  carries knife edge seals  44  which extend toward inner seals  50 ,  60  associated with the vane  42 . The vane  42  has a platform  46  that extends to a first arm  47  which is formed integrally with a mount structure  48 . The mount structure  48  carries an abradable seal material  50 . 
     The mount  48  and material  50  is fixed to the platform  46 , and will generally extend through a circumferential extent similar to that of platform  46 . 
     A second arm  52  extends inwardly from the platform  46  and may include a slot  54 . The slot  54  receives a pin  56  that is attached to a tab  58  from another seal mount  59 . The seal mount  59  mounts abradable seal material  60 . 
     The seal  60  extends circumferentially beyond the extent of any one of the Vane components  142  (see  FIG. 3 ). As shown, the vane components  142  may carry plural vanes  42 . One or more than two vanes may be included in components within the scope of this application. The fixed seal mount  48  and seal  50  (although not shown in this view) extend Between approximate limits  80 , shown in phantom in  FIG. 3 , generally about a similar circumferential extent as components  142 . Thus, the seal mount  48  and its abradable seal  50  do not extend to an adjacent vane component  142 , but instead are fixed with each vane component  142 . Stated another way, seal  60  extends for a greater circumferential extent than seal  50 . 
     On the other hand, as is clear, the continuous seal mount  59 , and its abradable seal  60  extends circumferentially beyond the extent of any one vane component. In practice, the mount  59  and seal material  60  may extend for a full ring. 
     The seals  50  and  60  are formed of a material that is more abradable than the surface of the platform  46  or mounts  59  and  48 . 
     In addition, as can be appreciated from  FIG. 2 , one of the seals  50  is positioned to be adjacent a seal  44  from one blade  40  on a first axial side of vane  42 , and the other seal  60  is positioned to be adjacent a seal  44  from a blade  40  on an opposed axial side. 
     The description as set forth above is relatively simplified, and in particular with regard to the seals  44 . In fact, the seals  44  may be completely separate from the turbine blades, and could be a continuous seal member. What is true is the two seals  44  shown in  FIG. 2  would be appreciated with separate rotors, and would rotate with those rotors. In addition, while one knife edge is shown for each seal  44 , any number of additional knife edges could be utilized. 
     Finally, while abradable seals are illustrated, the teachings of this application would extend to other types of seals, such as floating or non-contact seals (e.g., those available under the trade name “halo”). Such an embodiment is shown somewhat schematically in  FIG. 4 , wherein the rotating component  301  is not a knife edge. Instead, the non-contact or floating seal system  300  includes a seal member  302  that is movable relative to the mount portion  306 . Some fluid pressure  304  biases the seal portion  302  toward the rotating component  301 . It should be understood that this application extends to this type of seal, and any number of other types of seals. This type of non-contact seal would typically be provided on the circumferentially continuous seal portion. 
     The combination thus provides the benefit of both types of seal materials, and provides synergistic benefits in ensuring adequate and desirable sealing under all conditions. 
     Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.