Abstract:
A rotating component for a turbine engine includes a main component portion including a web and a platform located at a radially outboard portion of the web, relative to an axis of rotation of the rotating component. A snap surface is located at the platform and is configured to interlock the rotating component with an adjacent rotating component. A transition surface extends from the main component portion to the snap surface and includes two or more different radii.

Description:
BACKGROUND 
       [0001]    This disclosure relates to gas turbine engines, and more particularly to rotating components of gas turbine engines. 
         [0002]    Gas turbine engines, such as those used to power modern commercial and military aircrafts, generally include a compressor section to pressurize an airflow, a combustor section for burning hydrocarbon fuel in the presence of the pressurized air, and a turbine section to extract energy from the resultant combustion gases. The airflow flows along a gaspath through the gas turbine engine. 
         [0003]    The gas turbine engine includes a plurality of rotors arranged along an axis of rotation of the gas turbine engine, in both the compressor section and the turbine section. Some of these rotors are connected to axially adjacent rotors, spacers, or other rotating components, via interference fit, also known in the art as a “snap fit”. The rotor in general, and the snap flange of the rotor in particular can be a highly stressed area during operation of the gas turbine aircraft. It is desired to reduce stresses in this area to prolong the service life of the rotor. 
       SUMMARY 
       [0004]    In one embodiment, a rotating component for a turbine engine includes a main component portion including a web and a platform located at a radially outboard portion of the web, relative to an axis of rotation of the rotating component. A snap surface is located at the platform and is configured to interlock the rotating component with an adjacent rotating component. A transition surface extends from the main component portion to the snap surface and includes two or more different radii. 
         [0005]    Additionally or alternatively, in this or other embodiments the transition surface includes a first radius extending from the web to a transition point and a second radius extending from the transition point to the snap surface. 
         [0006]    Additionally or alternatively, in this or other embodiments the first radius is larger than the second radius. 
         [0007]    Additionally or alternatively, in this or other embodiments the transition point is radially outboard of the snap surface. 
         [0008]    Additionally or alternatively, in this or other embodiments the transition surface includes a first radius extending from the platform to a transition point and a second radius extending from the transition point to the snap surface. 
         [0009]    In another embodiment, a compressor rotor for a gas turbine engine includes a plurality of rotor blades and a main rotor portion supporting of the plurality of rotor blades. The main rotor portion includes a radially-extending web portion and a platform portion affixed to the web portion and supportive of the plurality of rotor blades. A snap surface is located at the platform portion and is configured to interlock the compressor rotor with an adjacent rotating component. A transition surface extends from the main rotor portion to the snap surface, the transition surface including two or more different radii. 
         [0010]    Additionally or alternatively, in this or other embodiments the transition surface includes a first radius extending from the web to a transition point and a second radius extending from the transition point to the snap surface. 
         [0011]    Additionally or alternatively, in this or other embodiments the first radius is larger than the second radius. 
         [0012]    Additionally or alternatively, in this or other embodiments the first radius is about two times the second radius. 
         [0013]    Additionally or alternatively, in this or other embodiments the transition point is radially outboard of the snap surface. 
         [0014]    Additionally or alternatively, in this or other embodiments the transition surface includes a first radius extending from the platform to a transition point and a second radius extending from the transition point to the snap surface. 
         [0015]    Additionally or alternatively, in this or other embodiments the adjacent rotating component is one of an adjacent compressor rotor or a compressor spacer. 
         [0016]    Additionally or alternatively, in this or other embodiments the snap surface defines an interference fit between the compressor rotor and the adjacent rotating component. 
         [0017]    In yet another embodiment, a gas turbine engine includes a turbine section, a combustor section to provide combustion gases to the turbine section, and a compressor section to compress an airflow and direct the compressed airflow toward the combustor. The compressor section includes a compressor rotor having a plurality of rotor blades and a main rotor portion supporting of the plurality of rotor blades. The main rotor portion includes a radially-extending web portion and a platform portion affixed to the web portion and supportive of the plurality of rotor blades. A snap surface is located at the platform portion and is configured to interlock the compressor rotor with an adjacent rotating component. A transition surface extends from the main rotor portion to the snap surface, the transition surface including two or more different radii. 
         [0018]    Additionally or alternatively, in this or other embodiments the transition surface includes a first radius extending from the web to a transition point and a second radius extending from the transition point to the snap surface. 
         [0019]    Additionally or alternatively, in this or other embodiments the first radius is larger than the second radius. 
         [0020]    Additionally or alternatively, in this or other embodiments the first radius is about two times the second radius. 
         [0021]    Additionally or alternatively, in this or other embodiments the transition point is radially outboard of the snap surface. 
         [0022]    Additionally or alternatively, in this or other embodiments the transition surface includes a first radius extending from the platform to a transition point and a second radius extending from the transition point to the snap surface. 
         [0023]    Additionally or alternatively, in this or other embodiments the adjacent rotating component is one of an adjacent compressor rotor or a compressor spacer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The subject matter which is regarded as the present disclosure is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0025]      FIG. 1  illustrates a schematic cross-sectional view of an embodiment of a gas turbine engine; 
           [0026]      FIG. 2  illustrates a schematic cross-sectional view of an embodiment of a compressor of a gas turbine engine; 
           [0027]      FIG. 3  illustrates a schematic cross-sectional view of another embodiment of a compressor of a gas turbine engine; and 
           [0028]      FIG. 4  illustrates a schematic cross-sectional view of an embodiment of a compressor rotor for a gas turbine engine. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]      FIG. 1  is a schematic illustration of a gas turbine engine  10 . The gas turbine engine generally has a fan  12  through which ambient air is propelled in the direction of arrow  14 , a compressor  16  for pressurizing the air received from the fan  12  and a combustor  18  wherein the compressed air is mixed with fuel and ignited for generating combustion gases. 
         [0030]    The gas turbine engine  10  further comprises a turbine section  20  for extracting energy from the combustion gases. Fuel is injected into the combustor  18  of the gas turbine engine  10  for mixing with the compressed air from the compressor  16  and ignition of the resultant mixture. The fan  12 , compressor  16 , combustor  18 , and turbine  20  are typically all concentric about a common central longitudinal axis of the gas turbine engine  10 . In some embodiments, the turbine  20  includes one or more turbine stators  22  and one or more turbine rotors  24 . Likewise, the compressor  16  includes one or more compressor rotors  26  and one or more compressor stators  28 . It is to be appreciated that while description below relates to compressors  16  and compressor rotors  26 , one skilled in the art will readily appreciate that the present disclosure may utilized with respect to turbine rotors  24 . 
         [0031]    Referring now to  FIG. 2 , The compressor  16  includes a compressor case  30 , in which the compressor rotors  26  are arranged along an engine axis  32  about which the compressor rotors  26  rotate. Each compressor rotor  26  includes a rotor disc  34  with a plurality of rotor blades  36  extending radially outwardly from the rotor disc  34 . In some embodiments, the rotor disc  34  and the plurality of rotor blades  36  are a single, unitary structure, an integrally bladed compressor rotor  26 . In other embodiments, the rotor blades  36  are each installed to the rotor disc  34  via, for example, a dovetail joint where a tab or protrusion at the rotor blade  36  is inserted into a corresponding slot in the rotor disc  34 . 
         [0032]    As shown in  FIG. 2 , axially adjacent compressor rotors  26  may be joined to each other, while in other embodiments, as shown in  FIG. 3 , the compressor rotor  26  may be joined to another rotating component, such as a spacer  38 . The compressor rotor  26  is secured to the adjacent rotating component by an interference fit, which in some embodiments is combined with another mechanical fastening, such as a plurality of bolts (not shown) to secure the components. 
         [0033]    Referring now to  FIG. 4 , a more detailed view of the interference fit, also referred to as a “snap fit”, between the compressor rotor  26  and the adjacent rotating component is shown. Compressor rotor  26 , as stated above, includes a plurality of rotor blades  36  secured to, and radially extending from a rotor disc  34 . In particular, the rotor blades  36  extend from a blade platform  40  portion of the rotor disc  34 . The blade platform  40  extends in a substantially axial direction, and includes a flowpath surface  42  that defines an inner boundary of a flowpath  44  of the gas turbine engine  10 . A radially inboard platform surface  46 , opposite the flowpath surface  42  and radially inboard therefrom, defines a rotor snap diameter  48 . The rotor snap diameter  48  interfaces with an adjacent component snap diameter  50  to join the compressor rotor  26  and the adjacent component  52 . 
         [0034]    In their respective free, unrestrained states, and when unjoined, the adjacent component snap diameter  50  is larger than the rotor snap diameter  48 . To join the components, the compressor rotor  26  may heated and/or the adjacent component  52  may be cooled to temporarily enlarge the rotor snap diameter  48  and/or temporarily cool the adjacent component snap diameter  50 , respectively. The components then may be joined, and when returned to ambient temperature the desired interference fit is achieved between the rotor snap diameter  48  and the adjacent component snap diameter  50 . 
         [0035]    The snap diameters  48 ,  50  are formed in the components by, for example, a grinding operation. The grinding operation is performed during manufacture after surface treatment of the compressor rotor  26  by, for example, shot peening. Any inadvertent damage to the peened surface during grinding requires the compressor rotor  26  to be retreated by shot peening. To reduce the risk of inadvertent damage to the compressor rotor  26 , a transition area  54  between the rotor snap diameter  48  and a web  56  of the rotor disc  34  includes a compound radius. The web  56  extends from an inner radial extent of the rotor disc  34  to the blade platform  40 . 
         [0036]    The transition area  54  includes a first radius  58  extending from the web  56  to a transition point  60  radially outboard of the snap diameter  48 . To minimize stresses and increase durability of the compressor rotor  26 , the first radius  58  is selected to be as large as practicable. A second radius  62  extends from the transition point  60  to the rotor snap diameter  48  and is smaller than first radius  58 . In some embodiments, the first radius  58  is about two times the second radius  62 . Further, in some embodiments, the first radius  58  is between about 50 and about 0.100″, and in other embodiments the second radius  62  is between about 0.020″ and about 0.050″. 
         [0037]    The transition area  54  including first radius  58  and second radius  62  is beneficial to the compressor rotor  26  and to the gas turbine engine  10  in several ways. The large first radius  58  reduces stresses on the compressor rotor  26  and improves durability of the compressor rotor  26 . Further, the smaller second radius  62  allows for snap diameter  48  to have a larger axial width greater than a compressor rotor with a single-radius transition. Also, the use of a relatively small second radius  62  enables an increase in first radius  58  to lower compressor rotor stresses. 
         [0038]    In some embodiments, adjacent component  52  includes a transition area  154 . Similarly, the transition area  154  includes a first radius  158  extending from a platform  140  to a transition point  160  radially inboard of the adjacent component snap diameter  50 . To minimize stresses and increase durability, the first radius  158  is selected to be as large as practicable. A second radius  162  extends from the transition point  160  to the adjacent component snap diameter  50  and is smaller than first radius  158 . In some embodiments, the first radius  158  is about two times the second radius  162 . Further, in some embodiments, the first radius  158  is between about 0.050″ and about 0.100″, and in other embodiments the second radius  162  is between about 0.020″ and about 0.050″. 
         [0039]    While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.