Abstract:
A feeder duct assembly for a gas turbine engine, which negates the need for a ball or axial joint in the duct for required for flexibility under thermal loading. The feeder duct assembly of the present innovation comprises an end fitting designed to meet flexibility requirements without compromising dynamic performance of the system with added weight from ball or axial joints in the ducts.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Turbine engines, and particularly gas or combustion turbine engines, are rotary engines that extract energy from a flow of combusted gases passing through the engine in a series of compressor stages, which include pairs of rotating blades and stationary vanes, through a combustor, and then onto a multitude of turbine stages, also including multiple pairs of rotating blades and stationary vanes. 
         [0002]    Feeder duct assemblies are provided about the turbine engine and provide conduits for the flow of various operating fluids to and from the turbine engine. One of the operating fluids is bleed air. In the compressor stages, bleed air is produced and taken from the compressor via feeder ducts. Bleed air from the compressor stages in the gas turbine engine can be utilized in various ways. For example, bleed air can provide pressure for the aircraft cabin, keep critical parts of the aircraft ice-free, or can be used to start remaining engines. Configuration of the feeder duct assembly used to take bleed air from the compressor requires rigidity under dynamic loading, and flexibility under thermal loading. Current systems use ball joints or axial joints in the duct to meet requirements for flexibility, which compromise system dynamic performance by increasing the weight of the system. 
         [0003]    Gas turbine engines have been used for land and nautical locomotion and power generation, but are most commonly used for aeronautical applications such as for airplanes, including helicopters. In airplanes, gas turbine engines are used for propulsion of the aircraft. 
       BRIEF DESCRIPTION 
       [0004]    In one aspect, embodiments of the innovation relate to a feeder duct assembly for a gas turbine engine which comprises a flexible end fitting, with the feeder duct assembly comprising an end fitting defining a fluid inlet to the gas turbine engine, a feeder duct fluidly coupled to the fluid inlet, a seal fluidly sealing the feeder duct to the end fitting, and a dynamic mount securing the feeder duct to the end fitting. 
         [0005]    In another aspect, embodiments of the innovation relate to a feeder duct assembly comprising an end fitting having an interface flange, a feeder duct having a terminal end and a circumferential flange with a circumferential seal encircling the feeder duct and located between the interface flange and the circumferential flange, at least one pair of biasing elements sandwiching a portion of the circumferential flange, and a fastener securing the circumferential flange and intermediate flange to the end fitting and compressing the pair of biasing elements. 
         [0006]    In yet another aspect, embodiments of the innovation relate to a method of securing a feeder duct to an end fitting of a gas turbine engine, the method comprising fluidly sealing a terminal end of the feeder duct to the end fitting while flexibly mounting the terminal end of the feeder duct to the end fitting. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    In the drawings: 
           [0008]      FIG. 1  is a schematic, sectional view of a gas turbine engine in accordance with various aspects described herein. 
           [0009]      FIG. 2  is a schematic assembled view of an example feeder duct assembly that can be utilized for a gas turbine engine in accordance with various aspects described herein. 
           [0010]      FIG. 3  is a schematic exploded view of an example feeder duct assembly that can be utilized for a gas turbine engine in accordance with various aspects described herein. 
           [0011]      FIG. 4  is a schematic cross-sectional view of an example feeder duct assembly that can be utilized for a gas turbine engine in accordance with various aspects described herein. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The described embodiments of the present innovation are directed to systems, methods, and other devices related to routing air flow in a turbine engine. For purposes of illustration, the present innovation will be described with respect to an aircraft gas turbine engine. It will be understood, however, that the innovation is not so limited and may have general applicability in non-aircraft applications, such as other mobile applications and non-mobile industrial, commercial, and residential applications. 
         [0013]      FIG. 1  is a schematic cross-sectional diagram of a gas turbine engine  10  for an aircraft. The engine  10  has a generally longitudinally extending axis or centerline  12  extending from forward  14  to aft  16 . The engine  10  includes, in downstream serial flow relationship, a fan section  18  including a fan  20 , a compressor section  22  including a booster or low pressure (LP) compressor  24  and a high pressure (HP) compressor  26 , a combustion section  28  including a combustor  30 , a turbine section  32  including a HP turbine  34 , and a LP turbine  36 , and an exhaust section  38 . 
         [0014]    The fan section  18  includes a fan casing  40  surrounding the fan  20 . The fan  20  includes a plurality of fan blades  42  disposed radially about the centerline  12 . The HP compressor  26 , the combustor  30 , and the HP turbine  34  form a core  44  of the engine  10 , which generates combustion gases. The core  44  is surrounded by core casing  46 , which can be coupled with the fan casing  40 . 
         [0015]    A HP shaft or spool  48  disposed coaxially about the centerline  12  of the engine  10  drivingly connects the HP turbine  34  to the HP compressor  26 . A LP shaft or spool  50 , which is disposed coaxially about the centerline  12  of the engine  10  within the larger diameter annular HP spool  48 , drivingly connects the LP turbine  36  to the LP compressor  24  and fan  20 . The portions of the engine  10  mounted to and rotating with either or both of the spools  48 ,  50  are also referred to individually or collectively as a rotor  51 . 
         [0016]    The LP compressor  24  and the HP compressor  26  respectively include a plurality of compressor stages  52 ,  54 , in which a set of compressor blades  58  rotate relative to a corresponding set of static compressor vanes  60 ,  62  (also called a nozzle) to compress or pressurize the stream of fluid passing through the stage. In a single compressor stage  52 ,  54 , multiple compressor blades  56 ,  58  can be provided in a ring and can extend radially outwardly relative to the centerline  12 , from a blade platform to a blade tip, while the corresponding static compressor vanes  60 ,  62  are positioned downstream of and adjacent to the rotating blades  56 ,  58 . It is noted that the number of blades, vanes, and compressor stages shown in  FIG. 1  were selected for illustrative purposes only, and that other numbers are possible. The blades  56 ,  58  for a stage of the compressor can be mounted to a disk  53 , which is mounted to the corresponding one of the HP and LP spools  48 ,  50 , respectively, with each stage having its own disk. The vanes  60 ,  62  are mounted to the core casing  46  in a circumferential arrangement about the rotor  51 . 
         [0017]    The HP turbine  34  and the LP turbine  36  respectively include a plurality of turbine stages  64 ,  66 , in which a set of turbine blades  68 ,  70  are rotated relative to a corresponding set of static turbine vanes  72 ,  74  (also called a nozzle) to extract energy from the stream of fluid passing through the stage. In a single turbine stage  64 ,  66 , multiple turbine blades  68 ,  70  can be provided in a ring and can extend radially outwardly relative to the centerline  12 , from a blade platform to a blade tip, while the corresponding static turbine vanes  72 ,  74  are positioned upstream of and adjacent to the rotating blades  68 ,  70 . It is noted that the number of blades, vanes, and turbine stages shown in  FIG. 1  were selected for illustrative purposes only, and that other numbers are possible. 
         [0018]    In operation, the rotating fan  20  supplies ambient air to the LP compressor  24 , which then supplies pressurized ambient air to the HP compressor  26 , which further pressurizes the ambient air. The pressurized air from the HP compressor  26  is mixed with fuel in the combustor  30  and ignited, thereby generating combustion gases. Some work is extracted from these gases by the HP turbine  34 , which drives the HP compressor  26 . The combustion gases are discharged into the LP turbine  36 , which extracts additional work to drive the LP compressor  24 , and the exhaust gas is ultimately discharged from the engine  10  via the exhaust section  38 . The driving of the LP turbine  36  drives the LP spool  50  to rotate the fan  20  and the LP compressor  24 . 
         [0019]    Some of the air from the compressor section  22  can be bled off via one or more feeder duct assemblies  80 , and be used for cooling of portions, especially hot portions, such as the HP turbine  34 , and/or used to generate power or run environmental systems of the aircraft such as the cabin cooling/heating system or the deicing system. In the context of a turbine engine, the hot portions of the engine are normally downstream of the combustor  30 , especially the turbine section  32 , with the HP turbine  34  being the hottest portion as it is directly downstream of the combustion section  28 . Air that is drawn off the compressor and used for these purposes is known as bleed air. 
         [0020]    Referring to  FIG. 2 , an exemplary feeder duct assembly  80  is illustrated and comprises a feeder duct  82  coupled to an end fitting  84  by a dynamic mount  90 . The dynamic mount  90  couples the feeder duct  82  to the end fitting  84  such that the feeder duct  82  is free to move relative to the end fitting  84  while still maintaining a fluid connection. The dynamic mount  90  provides for the feeder duct  82  to move axially, including reciprocation, as well as pivoting relative to the end fitting  84 . Thus, vibrations and other variable forces that tend to move the feeder duct  82  in a plurality of directions are accommodated without fatiguing the connection with the end fitting  84 . As the dynamic mount  90  is located at the junction of the feeder duct  82  and the end fitting  84 , the dynamic mount  90  does not add additional mass to the feeder duct  82 , which could function as a suspended mass also subject to the vibrations and other forces acting on the feeder duct  82 . The dynamic mount  90  can be in the form of any mechanism capable of coupling the feeder duct  82  to the end fitting  84  such as an E-type seal, spring systems, and compression seals. 
         [0021]    Referring to  FIG. 3 , the dynamic mount  90  is shown exploded to better illustrate its details in the environment of the feeder duct  82  and end fitting  84 . The feeder duct  82  terminates at a terminal end  100  and has an external duct flange  94 , or circumferential flange, spaced from the terminal end  100  so that the terminal end  100  of the feeder duct  82  can pass into the feeder duct assembly towards the end fitting  84 . The end fitting  84  comprises a face flange  102  or interface flange which defines a fluid inlet  86 . The dynamic mount  90  dynamically secures the duct flange  94  to the face flange  102 . By dynamically secures, it is meant that the fluid connection between the feeder duct  82  and the end fitting  84  is maintained while the feeder duct  82  is permitted to move as least one of axially, including reciprocation, or pivoting relative to the end fitting  84 . In this sense, the duct flange  94  and face flange  102  can be considered components of the dynamic mount  90 . 
         [0022]    The dynamic mount  90  further includes a seal assembly having a seal flange  88  holding a seal  96 , which can be a compressible seal, and biasing elements  98  (e.g., springs, etc.) dynamically coupling the seal flange  88  to the duct flange  94  and face flange  102 . 
         [0023]    Fasteners  104  retain the duct flange  94 , biasing elements  98 , seal flange  88 , and face flange  102  as a collective unit. The duct flange  94 , the seal flange  88 , and the face flange  102 , all comprise mounting openings  87  through which the fasteners pass. Similarly, the biasing elements  98  having openings through which the fasteners pass. 
         [0024]    The biasing elements  98  can be arranged in multiple pairs about the duct flange  94 . For example, the biasing elements  98  can include four Belleville springs pairs (as shown in  FIG. 3 ) with a pair located at each corner of the flanges  88 ,  94 ,  102 . However, other arrangements are contemplated and will vary depending on the shape and size of the feeder duct. 
         [0025]    The seal flange  88  is located between the duct flange  94  and the face flange  102  and can comprise an intermediate flange or collar  92 . The inner surface of the collar  92  can have a circumferential channel  93  in which the seal  96  is located. The seal  96 , or circumferential seal, can be any seal and is shown here as a diaphragm seal, which provides for the seal to remain in contact with the feeder duct  82  as it moves dynamically relative to the end fitting  84 . 
         [0026]    Referring to  FIG. 4 , the feeder duct assembly  80  is shown in an assembled condition, which serves to fluidly couple the feeder duct  82  to the fluid inlet  86 , by the terminal end  100  passing through the collar  92  of the seal flange  88  and opening up to the fluid inlet  86  of the end fitting  84 . In this assembled condition, the seal  96  is compressively retained by the collar  92  against the exterior of the feeder duct  82  to fluidly seal the feeder duct  82  relative to the end fitting  84 . 
         [0027]    The dynamic mount  90  dynamically secures the feeder duct  82  to the end fitting  84  with the fasteners  104  which pass through the aligned mounting openings  87 , the biasing elements  98 , the duct flange  94 , the seal flange  88 , and the face flange  102  to compressively retain the duct flange  94  with the biasing elements  98  and secure the duct flange  94  and the seal flange  88 , to the face flange  102  of the end fitting  84 . 
         [0028]    The biasing elements  98 , which are held under compression on both sides of the duct flange  94 , form a composite structure of the duct flange  94  interposed between the biasing elements  98 , resulting in a sandwiching of the duct flange  94  between the biasing elements  98 , while being constrained to the end fitting  84 , thereby enabling the duct flange  94  to move relative to the biasing elements  98  in response to movement of the feeder duct  82 . As the biasing elements  98  are under compression on each side of the duct flange  94 , the opposing spring forces biasing the duct flange  94  back to a neutral position. Thus any movement of the duct flange  94  off of the neutral position, which can be caused by the movement of the feeder duct  82 , is countered by the biasing elements  98 , which then return the duct flange  94  to its neutral position, where the forces substantially equal on each side of the duct flange  94 . 
         [0029]    More specifically, as a force acts on the feeder duct  82 , the resulting movements of the feeder duct  82  causes a movement of the duct flange  94  illustrated by arrows A. The movement is countered by the biasing elements  98  to return the duct flange  94  back to neutral position. Depending on the direction that the external force acts on the feeder duct  82 , the duct flange  94  can be axially moved, even reciprocated, relative to the end fitting  84 . It is also possible for the duct flange  94  to pivot relative to the end fitting  84 . For example, in  FIG. 4 , the top most portion of the duct flange  94  can move to the left and the bottom most portion of the duct flange  94  can move to the right as viewed in  FIG. 4 . This pivoting motion can be thought of as a front/back pivoting with respect to  FIG. 4 . There can also be a side-to-side pivoting, which would be in and out of the image of  FIG. 4 . There can also be combinations of these two movements. All of the movements are countered by the biasing elements  98 . 
         [0030]    With this structural configuration, a method for securing a feeder duct to an end fitting of a gas turbine engine includes fluidly sealing the terminal end  100  of the feeder duct  82  to the end fitting  84  while flexibly mounting the terminal end  100  of the feeder duct  82  to the end fitting  84 . Fluidly sealing the terminal end  100  of the feeder duct  82  to the end fitting  84  comprises circumferentially sealing the feeder duct relative to the end fitting, and flexibly mounting the terminal end  100  of the feeder duct  82  to the end fitting  84  comprises compressively retaining a portion of the terminal end  100  of the feeder duct to the end fitting. 
         [0031]    This written description uses examples to disclose the innovation, including the best mode, and also to enable any person skilled in the art to practice the innovation, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the innovation 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.