Abstract:
A micromixer of a turbine system is provided and the micromixer includes a plurality of pipes each having an inlet and an outlet for receiving flow and dispersing the flow to a combustor. Also provided is a non-uniform inlet arrangement defined by the inlets of the plurality of pipes, wherein at least one of the inlets extends to an axial location distinct from at least one other inlet.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to turbine systems, and more particularly to a micromixer. 
         [0002]    Turbine systems may include a micromixer, where air distribution to an individual air-fuel pipe should remain at a mean average value of the overall flow. The micromixer typically includes a plurality of pipes or tubes, each having an inlet, where the plurality of inlets are all located in a single, defined axial plane. Due to upstream conditions, such as the flow experiencing a sharp turn just prior to entering the inlets, non-uniform mass flow often prevails, thereby hindering overall system performance. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0003]    According to one aspect of the invention, a micromixer of a turbine system includes a plurality of pipes each having an inlet and an outlet for receiving flow and dispersing the flow to a combustor. Also provided is a non-uniform inlet arrangement defined by the inlets of the plurality of pipes, wherein at least one of the inlets extends to an axial location distinct from at least one other inlet. 
         [0004]    According to another aspect of the invention, a turbine system includes a combustor having an outer liner. Also included is a flow sleeve surroundingly enclosing the outer liner proximate a head end of the combustor, wherein air flows upstream between the flow sleeve and the outer liner. Further included is a micromixer disposed proximate the head end and including a plurality of pipe inlets, wherein the plurality of pipe inlets define a non-uniform inlet contour. 
         [0005]    According to yet another aspect of the invention, a turbine system includes a combustor. Also included is a micromixer disposed proximate a head end of the combustor, the micromixer including a plurality of pipes each extending along a longitudinal axis, each of the plurality of pipes extending along a longitudinal axis, each of the plurality of pipes having an inlet and an outlet. Further included is a transverse plane aligned relatively perpendicular to the longitudinal axis and located proximate to at least one of the inlets of the plurality of pipes, wherein at least one inlet of the plurality of pipes extends upstream through the transverse plane, thereby defining a non-uniform inlet arrangement. 
         [0006]    These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0007]    The subject matter, which is regarded as the invention, 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 invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0008]      FIG. 1  is a perspective view of a turbine system having a micromixer located in a head end; 
           [0009]      FIG. 2  is a side elevational view of a flow preparing to enter a plurality of pipes of the micromixer; 
           [0010]      FIG. 3  is a side elevational view of an embodiment of the micromixer having pipes of varying lengths; 
           [0011]      FIG. 4  is a side elevational view of an embodiment of the micromixer having non-linear pipes; 
           [0012]      FIG. 5  is a top plan view of the micromixer having non-linear pipes of  FIG. 4 ; 
           [0013]      FIG. 6  is a perspective view of an embodiment of the micromixer including an angled face having a plurality of elliptical apertures that align in a flush relationship with a plurality of inlets of the plurality of pipes; and 
           [0014]      FIG. 7  is an enlarged perspective view of an embodiment of the micromixer including the angled face, wherein the plurality of inlets of the plurality of pipes extend through the apertures. 
       
    
    
       [0015]    The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    Referring to  FIG. 1 , illustrated is a turbine system  10  having a combustor section  12  and a head end  14 . The head end  14  is disposed at an adjacent upstream location of the combustor section  12  and includes a micromixer  16 . The micromixer  16  includes a plurality of sectors  18  that each comprise a plurality of pipes  20 . The combustor section  12  is defined by an outer liner  22  that extends to an upstream end  24 . Spaced radially outwardly of the outer liner  22 , and surroundingly enclosing the outer liner  22 , is a flow sleeve  26 . A flow  28  of air passes upstream within an air passage  30  defined by the outer liner  22  and the flow sleeve  26  to the upstream end  24  of the outer liner  22 . 
         [0017]    Referring to  FIG. 2 , upon reaching the upstream end  24  of the outer liner  22 , the flow  28  makes an abrupt turn just prior to entering the micromixer  16 . The plurality of pipes  20  each include an inlet  32  for receiving the flow  28 . It is apparent that pipes disposed at an outer region of the plurality of sectors  18  (i.e., proximate the outer liner  22 ) do not receive the flow  28  at a pressure or flow rate comparable to that of pipes disposed proximate a central region of the plurality of sectors  18 , due to the abrupt turn necessitated by the arrangement illustrated in  FIG. 2 . 
         [0018]    Referring to  FIG. 3 , the inlets  32  of the plurality of pipes  20  extend upstream to various axial locations. In the illustrated example, a non-uniform inlet arrangement  34  in the form of a parabolic formation results from the varying inlet  32  extension. Such an embodiment reduces the formation of vortices present in the flow  28  after making the abrupt turn, thereby resulting in a more uniform overall mass flow throughout the plurality of pipes  20 . The parabolic formation induces pressure differences seen at the inlet  32  of the plurality of pipes  20 . The non-uniform inlet arrangement  34  may be manipulated and fine-tuned to produce a uniform mass flow throughout the plurality of pipes  20 . 
         [0019]    Referring to  FIGS. 4 and 5 , it is shown that in addition to a non-uniform inlet arrangement  34  that includes a variance of the axial location for the inlets  32  of the plurality of pipes  20 , an introduction of curvature on the plurality of pipes  20  proximate the inlets  32  enhances overall mass flow uniformity throughout the micromixer  16 . This is achieved by angling regions of the plurality of pipes  20  proximate the inlets  32 , thereby forming angled inlet portions  36  that are aligned to more capably receive the flow  28  in a manner that does not result in unnecessary pressure drops throughout the respective pipes  20 . 
         [0020]    Referring to  FIG. 6 , an embodiment of the micromixer  16  is illustrated having an angled face  40  that includes a plurality of apertures  42 . The plurality of apertures  42  are aligned to receive at least a portion of the inlets  32  of the plurality of pipes  20 . The angled face  40  is oriented such that pipes proximate an outer region of the sector  18  are shorter in length than that of pipes proximate the more radially inward pipes. The angled face  40  improves uniformity of air distribution into the head end  14  by allowing the flow  28  to avoid taking an abrupt turn into the head end  14  region, instead making the transition more gradually and providing a more uniform distribution of the flow  28 , while reducing pressure drop throughout the plurality of pipes  20 . 
         [0021]    In the illustrated embodiment, the inlets  32  of the plurality of pipes  20  extend to meet the plurality of apertures  42  in a flush manner, such that each surface of the inlets  32  slopes in a downstream direction as each surface moves radially outward. This configuration provides for the flush relationship between each inlet  32  surface and corresponding apertures  42 . The flush relationship between the inlet  32  and the plurality of apertures  42  causes the inlet  32  geometry to be relatively elliptical. 
         [0022]    Referring to  FIG. 7 , an embodiment of the micromixer  16  having the angled face  40  is shown. Similar to the embodiment described with respect to  FIG. 6 , the angled face  40  includes the plurality of apertures  42  that are configured to receive the inlets  32  of the plurality of pipes  20 . In this embodiment, a surface  44  of each inlet  32  is flat and in a single plane that is substantially perpendicular to a longitudinal axis of the respective pipe. Rather than forming a flush relationship where the inlets  32  extend only to the plurality of apertures  42 , the inlets  32  extend beyond the plurality of apertures  42  to an axial location upstream of the respective apertures  42 , thereby forming circular entries to the plurality of pipes  20 . 
         [0023]    Although the angled face  40  described and shown in  FIGS. 6 and 7  have a specific direction of angulation, that being less than relatively 90 degrees between the angled face and the longitudinal axis of the plurality of pipes  20 , it should be appreciated that the angle of the angled face  40  may vary. Additionally, the angled face  40  may not necessarily be disposed in a single plane, instead taking on any contoured shape that provides a suitable approach for the flow  28  into the micromixer  16 . 
         [0024]    The micromixer  16  embodiments described above advantageously provide enhanced uniformity for head end  14  flow distribution into the plurality of pipes  20 , as well as a reduction in pressure drop seen across the plurality of pipes  20 . These benefits result in more uniform fuel-air mixing and an improvement in overall turbine system  10  efficiency. 
         [0025]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.