Abstract:
One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique reheat system for a gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and reheat systems. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims benefit of U.S. Provisional Patent Application No. 61/427,737, filed Dec. 28, 2010, entitled Gas Turbine Engine and Reheat System, which is incorporated herein by reference. 
     
    
     GOVERNMENT RIGHTS 
       [0002]    The present application was made with United States government support under Contract No. F33615-03-2300-DO-2 awarded by the United States Air Force. The United States government may have certain rights in the present application. 
     
    
     FIELD OF THE INVENTION 
       [0003]    The present invention relates to gas turbine engines, and more particularly, to a gas turbine engine hot section component and method for making the same. 
       BACKGROUND 
       [0004]    Gas turbine engines and reheat systems for gas turbine engines remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology. 
       SUMMARY 
       [0005]    One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique reheat system for a gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and reheat systems. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0007]      FIG. 1  schematically illustrates some aspects of a non-limiting example of a gas turbine engine in accordance with an embodiment of the present invention. 
           [0008]      FIG. 2  depicts some aspects of a non-limiting example of a reheat system in accordance with an embodiment of the present invention. 
           [0009]      FIG. 3  schematically illustrates the output of a previous reheat system 
           [0010]      FIG. 4  schematically illustrates some aspects of a non-limiting example of the calculated output of a reheat system in accordance with an embodiment of the present invention. 
           [0011]      FIGS. 5A-5C  illustrate cross sections through the reheat system illustrated in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the invention is intended by the illustration and description of certain embodiments of the invention. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present invention. Further, any other applications of the principles of the invention, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the invention pertains, are contemplated as being within the scope of the present invention. 
         [0013]    Referring now to the drawings, and in particular  FIG. 1 , some aspects of a non-limiting example of a gas turbine engine  10  in accordance with an embodiment of the present invention are depicted. In one form, gas turbine engine  10  is an air vehicle propulsion power plant. In other embodiments, gas turbine engine  10  may be an aircraft auxiliary power unit, a land-based engine or a marine engine. In one form, gas turbine engine  10  is a turbofan engine. In other embodiments, gas turbine engine  10  may be a single or multi-spool turbofan, turboshaft, turbojet, and/or turboprop gas turbine and/or combined cycle engine. 
         [0014]    Gas turbine engine  10  includes a compressor system  12 , a primary combustion system  14 , a turbine system  16 , a reheat combustion system  18  and a turbine system  20 . Compressor system  12  includes a plurality of blades and vanes in one or more stages configured to pressurize incoming air. Combustion system  14  is fluidly disposed between compressor system  12  and turbine system  16 . Combustion system  14  is operative to mix fuel with air received from compressor system  12  and combust the mixture. Turbine system  16  is operative to extract energy from the hot gases exiting combustion system  14 . Reheat combustion system  18  is fluidly disposed downstream of turbine system  16  and upstream of turbine system  20 . Reheat combustion system is operative to add heat to the got gases exiting turbine system  16 , prior to the hot gases entering turbine system  20 . Turbine system  16  and turbine system  20  each include rotating turbine blades (not shown) for extracting power from the hot gases. In one form, turbine system  16  and turbine system  20  include stationary turbine vanes. In other embodiments, turbine systems  16  and  20  may employ counter-rotating blades in addition to or in place of turbine vanes. In one form, turbine system  16  and turbine system  20  drive separate shafts. In other embodiments, turbine  16  and turbine  20  may be mechanically coupled to the same shaft. 
         [0015]    During the operation of gas turbine engine  10 , air is drawn into the inlet of compressor system  12 , pressurized and discharged into combustion system  14 . Fuel is mixed with the pressurized air in combustion system  14 , which is then combusted. The combustion products are directed into turbine system  16 , which extracts energy in the form of mechanical shaft power to drive compressor system  12 . The hot gases exiting turbine system  16  are directed past reheat combustion system  18 , which adds thermal energy to the hot gases in the form of a reheat flow. Turbine system  20  extracts energy in the form of mechanical shaft power from the reheated hot gases, e.g., to drive a fan system (not shown). In other embodiments, turbine system  20  may be operative to drive all or part of compressor system  12 . In still other embodiments, turbine system  20  may be operative to drive a gearbox, a generator, a pump and/or other mechanical power absorbing devices. 
         [0016]    Referring now to  FIG. 2  in conjunction with  FIG. 1 , some aspects of a non-limiting example of reheat combustion system  18  in accordance with an embodiment of the present invention are described. Reheat combustion system  18  is a secondary combustor of gas turbine engine  10 , and includes a structure  22  and a structure  24 . Structure  22  includes a cavity  26  oriented along an engine  10  circumferential direction  27 . Cavity  26  is fed by a plurality of swirl injection ports  28  spaced apart circumferentially around cavity  26 . In one form, swirl injection ports  28  supply fuel and air to cavity  22 . In other embodiments, fuel and/or air may be supplied by means not shown. In one form, cavity  26  is a combustion reaction cavity and is operative to provide a reheat flow to structure  24 . In a particular form, cavity  26  is a secondary combustor of engine  10  that contains the reheat combustion process&#39; primary zone. In other embodiments, cavity  26  may contain not only the primary zone, but other combustion process zones as well, e.g., one or both of the intermediate zone and the dilution zone. In still other embodiments, cavity  26  may not be a combustion reaction cavity. In one form, the combustion process is initiated via auto ignition by introducing fuel into a pressurized high temperature flow that includes oxygen. In other embodiments, the combustion process may be initiated by other means, e.g., spark ignition, detonation or catalysis in addition to or in place of auto ignition. 
         [0017]    Structure  24  is configured in material and geometry for operation in a hot section flowpath downstream of combustor  14 . Structure  24  has a body  30  extending between a tip portion  32  and a hub portion  34 . Body  30  includes an internal cavity  36  and an exhaust port arrangement  38 . In one form, body  30  is an airfoil. In a particular form, body  30  is an inter-turbine nozzle guide vane. In other embodiments, structure  24  may take other forms, and may be, for example and without limitation, a strut that does not have an airfoil cross section, or any other form. In one form, structure  24  is disposed within a turbine flowpath  40  defined by an outer flowpath wall  42  and an inner flowpath wall  44 . Flowpath  40  is the flowpath for engine  10  core flow. In one form, structure  24  is operative to transmit radial loads through turbine flowpath  40 . In other embodiments, structure  24  may be operative to transmit any one or more of radial loads, axial loads and circumferential loads. In still other embodiments, structure  24  may not be operative to transmit loads through turbine flowpath  40 . In one form, flowpath walls  42  and  44  are formed separately from structure  24 . In other embodiments, part or all of one or both of flowpath walls  42  and  44  may be formed integrally with structure  24 . In still other embodiments, part or all of one or both of flowpath walls  42  and  44  are otherwise affixed to, coupled to, assembled with and/or disposed adjacent to structure  24 . 
         [0018]    Cavity  36  extends in a spanwise direction  46  between tip portion  32  and hub portion  34  of body  30 . Cavity  36  is a reheat flow distribution cavity that is operative to distribute reheat flow to flowpath  40  via exhaust port arrangement  38 . In one form, distribution cavity  36  is a combustion reaction cavity. In other embodiments, cavity  36  may not be a combustion reaction cavity. In one form, cavity  36  has a centerline  50 . In one form, centerline  50  extends not only in spanwise direction  46 , but also extends in circumferential direction  27  and in a flowpath direction  48  representative of the general direction of flow of hot gases through turbine flowpath  40 . In other embodiments, centerline  50  may extend in only one or two of spanwise direction  46 , circumferential direction  27  and flowpath direction  48 . Spanwise direction  46 , circumferential direction  27  and flowpath direction  48  form a three-dimensional cylindrical coordinate system that is used to define the extents of cavity  36 . In other embodiments, other three-dimensional coordinate systems or two dimensional systems may be employed. 
         [0019]    Cavity  36  includes an inlet portion  52 . Inlet portion  52  is operative to receive a reheat flow from cavity  26  of structure  22  for distribution into flowpath  40  and turbine system  20  via flowpath  40 . In one form, inlet portion  52  is disposed in tip portion  32  of body  30 . In other embodiments, inlet portion  52  may be located in hub portion  34 , e.g., in embodiments wherein reheat flow is supplied to cavity  36  from radially inward of structure  24 . In still other embodiments, more than one inlet portion may be employed, e.g., at one or more of tip portion  32 , hub portion  34  or one or more locations therebetween. 
         [0020]    Reheat flow is a hot gas flow having a higher temperature than the main flowpath gases approaching structure  24  in flowpath direction  48 , e.g., from a turbine stage upstream of structure  24 , which is used to increase the temperature of those gases flowing in flowpath direction  48  from upstream of structure  24 . In one form, the reheat flow received into cavity  36  is a combustion process intermediate zone flow. In other embodiments, the reheat flow received into cavity  36  may be a combustion process primary zone or dilution zone flow. In still other embodiments, the reheat flow received into cavity  36  may be combustion products downstream of a dilution zone. In still other embodiments, the reheat flow may be hot gases and fuel, e.g., wherein the primary combustion zone is fully or partially contained within cavity  36 . 
         [0021]    Exhaust port arrangement  38  is operative to expose cavity  36  to turbine flowpath  40  and to discharge the reheat flow into turbine flowpath  40  to reheat the gases passing through turbine flowpath  40  into turbine system  20 . In one form, exhaust port arrangement  38  is located on the suction side of body  30  (e.g., with body  30  in the form of an airfoil). In other embodiments, exhaust port arrangement  38  may be positioned at other locations on body  30 . Spanwise direction  46 , circumferential direction  27  and flowpath direction  48  form a three-dimensional cylindrical coordinate system that is used to define the extents of exhaust port arrangement  38 . In other embodiments, other three-dimensional coordinate systems or two dimensional systems may be employed. 
         [0022]    It is desirable that the distribution of reheat flow exiting exhaust port arrangement  38  be approximately uniformly in spanwise direction  46 . A uniform distribution of reheat flow in spanwise direction  46  reduces adverse impact on the life of turbine system  20  components downstream of structure  24  relative to similar systems not employing reheat, and relative to reheat systems that do not provide a uniform distribution of reheat flow. In addition, a uniform distribution of reheat flow in spanwise direction  46  reduces adverse impacts to engine  10  efficiency, such as would occur due to changes in incidence angle along spanwise direction  46  of the core flow in flowpath  40  during reheat operation, and which would occur as due to changes in incidence angle as between engine  10  operation with reheat operation and engine  10  operation without reheat operation. 
         [0023]    However, the inventors have determined that some previous reheat systems deliver most of the reheat flow at spanwise locations immediately adjacent to the reheat flow source (e.g., the reheat flow source being akin to inlet portion  52 , wherein most of the reheat flow is delivered to the flowpath via the portions of the exhaust arrangement immediately adjacent to the reheat flow source). For example, referring now to  FIG. 3 , the bulk of the flow distribution output by a previous reheat system is schematically illustrated. In the example of  FIG. 3 , one previous reheat system employed an exhaust port arrangement having a uniform flow area in the spanwise direction (i.e., uniform width of the exhaust port opening in the spanwise direction from tip to hub). The previous reheat system was analyzed by subdividing the exhaust port flow area into 10% control volume increments. Because the width of the exhaust port is uniform, each control volume increment corresponds to 10% of the height of the exhaust port. The flow distribution was found to yield approximately 67% of the reheat flow exiting the exhaust port via the upper 10% of the exhaust port height in spanwise direction (adjacent to the reheat flow source at the tip of the previous system); approximately 15% of the reheat flow exiting the exhaust port in the second 10% increment of the exhaust port height in the spanwise direction; approximately 9% of the reheat flow exiting the exhaust port in the third 10% increment of the exhaust port height in the spanwise direction; and most of the balance of the reheat flow (not shown) exiting the exhaust port in the next 10% increment of the exhaust port height in the spanwise direction. 
         [0024]    The inventors determined that by controlling unit flow area of exhaust port arrangement  38  based on local pressure gradients, the uniformity of distribution in spanwise direction  46  of reheat flow from exhaust port arrangement  38  may be improved. In one form, the unit flow area of exhaust port arrangement  38  is the flow area per unit height in spanwise direction  46 . In other embodiments, unit flow area may be the flow area per unit length along any two or three dimensional reference curve, e.g., including the centerline of exhaust port arrangement  38 . One such pressure gradient is a distribution cavity pressure gradient, which is the pressure gradient inside cavity  36 , e.g., as measured along centerline  50  or in spanwise direction  46 . In other embodiments, the variation in pressure may be considered along any two or three dimensional reference curve, e.g., including centerline  50  of cavity  36 . Another such pressure gradient is an exhaust pressure gradient, which is the pressure gradient normal to cavity  36 , e.g., normal to centerline  50 , in the direction of flow from cavity  36  into flowpath  40 . The inventors determined that the exhaust pressure gradient varies not only with the pressure inside cavity  36 , but also varies based on location within flowpath  40 . For example, the pressure in flowpath  40  varies in flowpath direction  48 , spanwise direction  46 , and circumferential direction  27 . 
         [0025]    The inventors also determined that by controlling the cross sectional area of cavity  36  based on the pressure gradients, the uniformity of distribution in spanwise direction  46  of reheat flow from exhaust port arrangement  38  may be improved. In addition, the inventors found that the pressure in flowpath  40  varies with location, e.g., in flowpath direction  48 , or along the chord of body  30  (e.g., in one or both of flowpath direction  48  and circumferential direction  27 , depending upon the shape of body  30 ). The inventors determined that the distribution of reheat flow may also be enhanced by considering the variation in pressure in flowpath direction  48  and the variation in pressure in circumferential direction  27 . That is, the inventors determined that the exhaust pressure gradient varies not only with the pressure inside cavity  36 , but also varies based on location within flowpath  40 . For example, the pressure in flowpath  40  varies in flowpath direction  48 , in spanwise direction  46 , and in circumferential direction  27 . In one form, the geometries of cavity  36  and of exhaust port arrangement  38  are varied along flowpath direction  48  and circumferential direction  36  with location in spanwise direction  46  to take advantage of the variations in pressure in flowpath  40  in order to improve the distribution of reheat flow. 
         [0026]    In order to determine the geometry of exhaust port arrangement  38  and cavity  36 , various methods may be employed. In one relatively simply approach, exhaust port arrangement  38  is subdivided into a number of control volumes. In one example, 10 control volumes between the tip and hub of body  30  were selected, e.g., as illustrated in  FIG. 4 . The flow per unit area, e.g., per control volume, given by q/A, is a function of the pressure gradient, as set forth in Equation 1: 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       q 
                       A 
                     
                     = 
                     
                       f 
                        
                       
                         ( 
                         
                           ∇ 
                           P 
                         
                         ) 
                       
                     
                   
                   , 
                 
               
               
                 
                   ( 
                   
                     Equation 
                      
                     
                         
                     
                      
                     1 
                   
                   ) 
                 
               
             
           
         
       
     
         [0027]    Where q is flow rate, A is area and P is pressure. 
         [0028]    Preferably, the reheat flow exiting exhaust port arrangement  38  is evenly distributed, such that the flow from each control volume of exhaust port arrangement  38  is the same, e.g., as set forth in Equation 2: 
         [0000]      q ni ,=constant,   (Equation 2)
 
         [0029]    where n indicates the normal direction relative to the slot, and hence q ni  is the i th  control volume flow from exhaust port arrangement  38  into flowpath  40 , e.g., normal to the slot; and 
         [0030]    where i=10 in the present example (10 control volumes). The number of control volumes may vary with the needs of the application. 
         [0031]    The total reheat flow from exhaust arrangement  38  is given by Equation 3: 
         [0000]        q   total =sum( q   ni )   (Equation 3)
 
         [0032]    The flow in cavity  36  is given by equation 4: 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       q 
                       si 
                     
                     = 
                     
                       
                         
                           ∑ 
                           
                             j 
                             = 
                             1 
                           
                           i 
                         
                          
                         
                           q 
                           nj 
                         
                       
                       = 
                       
                         
                           q 
                           
                             s 
                             , 
                             
                               i 
                               - 
                               1 
                             
                           
                         
                         + 
                         
                           q 
                           
                             n 
                             , 
                             
                               i 
                               - 
                               1 
                             
                           
                         
                       
                     
                   
                   , 
                 
               
               
                 
                   ( 
                   
                     Equation 
                      
                     
                         
                     
                      
                     4 
                   
                   ) 
                 
               
             
           
         
       
     
         [0033]    where s indicates the direction along cavity  36 , and hence q si  is the i th  control volume flow in cavity  36  (i.e., the reheat flow from one control volume to the next within cavity  36  in spanwise direction  46  or centerline  50 ). 
         [0034]    The flow area for each control volume for cavity  36  and for exhaust port arrangement  38  is given by Equation 5: 
         [0000]    
       
         
           
             
               
                 
                   
                     
                       
                         A 
                         si 
                       
                        
                       
                         dp 
                         
                           ds 
                           i 
                         
                       
                     
                     = 
                     
                       
                         ( 
                         
                           i 
                           - 
                           1 
                         
                         ) 
                       
                        
                       
                         A 
                         ni 
                       
                        
                       
                         dp 
                         
                           dn 
                           
                             i 
                              
                             
                                 
                             
                           
                         
                       
                     
                   
                   , 
                 
               
               
                 
                   ( 
                   
                     Equation 
                      
                     
                         
                     
                      
                     5 
                   
                   ) 
                 
               
             
           
         
       
     
         [0035]    Wherein A si  is the cross-sectional area of cavity  36  for the i th  control volume; A ni  is the flow area for exhaust port arrangement  38  for the i th  control volume; dp/ds i  is the pressure gradient along cavity  36  for the i th  control volume; and dp/dn i  is the pressure gradient between exhaust port arrangement  38  and flowpath  40  at the i th  control volume. 
         [0036]    In one form, Equations 1-5 are employed to obtain the shape of cavity  36  and exhaust port arrangement  38 . In other embodiments, Equations 1-5 are employed to obtain preliminary results, which are then refined using commercially available or in-house computer code. In still other embodiments, other methods may be employed to obtain shape of cavity  36  and exhaust port arrangement  38 . 
         [0037]    Referring now to  FIGS. 5A-5C  in conjunction with  FIG. 2 , in order to promote uniform flow distribution, the present non-limiting example includes the following three geometric design features: (1) a width W of exhaust port arrangement  38  that varies in spanwise direction  46 ; (2) a cross sectional flow area of cavity  36  that varies in spanwise direction  46 ; and (3) a centerline of cavity  36  and/or of exhaust port arrangement  38  that varies in location along flowpath direction  48  and circumferential direction  27  with location in spanwise direction  46 . In other embodiments, any one or more of the referenced geometric design features may be employed, alone or in combination with another of the geometric design features. In one form, the centerline of exhaust port arrangement  38  and centerline  50  of cavity  36  have the same axial position in flowpath direction  48 , and hence are coincident in the direction of view of  FIG. 2 . In other embodiments, exhaust port arrangement  38  may have a different centerline location than centerline  50  of cavity  36 . 
         [0038]    All three of the aforementioned geometric design features are present in the example described herein. That is, exhaust port arrangement  38  width W, e.g., as measured in flowpath direction  48 , varies with location in spanwise direction  46 . For example, width W 1  in the tip region of body  30  is less than width W 2  in the mid-span region of body  30 , which is less than width W 3  in the hub region of body  30 . In one form, width W varies based on one or more pressure gradients at the location in spanwise direction  46 , e.g., at a selected engine operating condition. In a particular form, the pressure gradients used to determine the width W of exhaust port arrangement  38  at each location along spanwise direction  46  are (i) the distribution cavity pressure gradient; and (ii) the exhaust pressure gradient normal to cavity  36 . In other embodiments, other pressure gradients in addition to or in place of those described herein may be employed. In one form, width W of exhaust port arrangement  38  increases with distance from the inlet portion  52  of the cavity  36 . 
         [0039]    In addition, cavity  36  has a cross-sectional area that varies with location in spanwise direction  46 . For example cross sectional area A 1  is greater than cross sectional area A 2 , which is greater than cross sectional area A 3 . In one form, the cross sectional area varies based on the pressure gradient at the location in spanwise direction  46 , e.g., at a selected engine operating condition. In a particular form, the pressure gradients used to determine the cross-sectional area of cavity  36  at each location along spanwise direction  46  are (i) the distribution cavity pressure gradient; and (ii) the exhaust pressure gradient normal to cavity  36 . In other embodiments, other pressure gradients in addition to or in place of those described herein. In one form, cavity  36  has a cross-sectional area that decreases with distance from inlet portion  52 . 
         [0040]    Further, cavity  36  and exhaust port arrangement  38  are configured with centerlines  50  that vary in location along flowpath direction  48  and circumferential direction  27  based on the pressure gradients, e.g., at a selected engine operating condition, e.g., to take advantage of lower pressures in flowpath  40  near the hub trailing edge  54  of body  30  in the present example. For example, the distance L 1  from the leading edge of body  30  in flowpath direction  48  to the center of exhaust port arrangement  38  is less than distance L 2  from the leading edge of body  30  in flowpath direction  48  to the center of exhaust port arrangement  38 , which is less than distance L 3  from the leading edge of body  30  in flowpath direction  48  to the center of exhaust port arrangement  38 . 
         [0041]    As set forth above all three of the aforementioned geometric design features are employed in the example described and illustrated herein. In other embodiments, only one or two of the aforementioned geometric design features may be employed. 
         [0042]    In one form, exhaust port arrangement  38  is an elongate slot that extends from tip portion  32  to a hub portion  34 . In other embodiments, exhaust port arrangement may take other forms. For example, in some embodiments, exhaust port arrangement  38  may take the form of a plurality of openings that have widths or average widths that increase in spanwise direction  46  away from inlet portion  52 . 
         [0043]    The distribution of reheat flow obtained from a non-limiting example of cavity  36  and exhaust port arrangement  38  yielded the fairly uniform results depicted in  FIG. 4 , wherein the reheat flow from the uppermost control volume (# 10 ) (adjacent to the tip) is approximately 15% of the total reheat flow; the reheat flow from the next control volume (# 9 ) is approximately 13% of the total reheat flow; the reheat flow from the next control volume (# 8 ) is approximately 12% of the total reheat flow; the reheat flow from the next control volume (# 7 ) is approximately 10% of the total reheat flow; the reheat flow from the next control volume (# 6 ) is approximately 8% of the total reheat flow; the reheat flow from the next control volume (# 5 ) is approximately 6% of the total reheat flow; the reheat flow from the next control volume (# 4 ) is approximately 9% of the total reheat flow; the reheat flow from the next control volume (# 3 ) is approximately 11% of the total reheat flow; the reheat flow from the next control volume (# 2 ) is approximately 9% of the total reheat flow; and the reheat flow from the bottom control volume (# 1 ) (adjacent the hub) is approximately 7% of the total reheat flow. In other embodiments, other distributions may be obtained. 
         [0044]    Embodiments of the present invention include a gas turbine engine hot section component, comprising: a flowpath structure configured for operation in a gas turbine engine flowpath downstream of a primary combustor of the gas turbine engine, wherein the flowpath structure includes: a body having a tip portion and a hub portion, wherein the body includes a cavity therein extending in a spanwise direction between the tip portion and the hub portion; wherein the cavity includes an inlet portion operative to receive a reheat flow into the cavity; and an exhaust port arrangement operative to expose the cavity to the gas turbine engine flowpath, wherein the exhaust port arrangement is configured with a width in a flowpath direction that varies with location in the spanwise direction based on a pressure gradient at the location in the spanwise direction at a selected engine operating condition. 
         [0045]    In a refinement, the exhaust port arrangement is configured with a centerline that varies in location along a flowpath direction based on the pressure gradient. 
         [0046]    In another refinement, the cavity has a cross-sectional area that varies with location in the spanwise direction based on the pressure gradient. 
         [0047]    In yet another refinement, the cavity has a cross-sectional area that decreases with distance from the inlet portion of the cavity. 
         [0048]    In still another refinement, the width of the exhaust port arrangement increases with distance from the inlet portion of the cavity. 
         [0049]    In yet still another refinement, the exhaust port arrangement is an elongate slot. 
         [0050]    In a further refinement, the body is an airfoil. 
         [0051]    In a yet further refinement, the cavity is a combustion reaction cavity. 
         [0052]    Embodiments of the present invention include a gas turbine engine, comprising: a compressor system; a primary combustor; a turbine system including a hot section component, the hot section component including: a flowpath structure configured for operation in a gas turbine engine flowpath downstream of a primary combustor of the gas turbine engine, wherein the flowpath structure includes: a body having a tip portion and a hub portion, wherein the body includes a cavity therein extending in a spanwise direction between the tip portion and the hub portion; wherein the cavity includes an inlet portion operative to receive a reheat flow for distribution to the turbine system; and an exhaust port arrangement operative to expose the cavity to the gas turbine engine flowpath, wherein the exhaust port arrangement is configured with a width in a flowpath direction that varies with location in the spanwise direction based on a pressure gradient at the location in the spanwise direction at a selected engine operating condition. 
         [0053]    In a refinement, the exhaust port arrangement is configured with a centerline that varies in location in a flowpath direction based on the pressure gradient. 
         [0054]    In another refinement, the cavity has a cross-sectional area that varies with location in the spanwise direction based on the pressure gradient. 
         [0055]    In yet another refinement, the cavity has a cross-sectional area that decreases with distance from the inlet portion of the cavity. 
         [0056]    In still another refinement, the width of the exhaust port arrangement increases with distance from the inlet portion of the cavity. 
         [0057]    In yet still another refinement, the exhaust port arrangement is an elongate slot. 
         [0058]    In a further refinement, the body is an airfoil. 
         [0059]    In a yet further refinement, the cavity is a combustion reaction cavity. 
         [0060]    In a still further refinement, the inlet portion is operative to receive a reheat flow from a primary zone of a secondary combustor the gas turbine engine. 
         [0061]    In another further refinement, the pressure gradient includes a pressure gradient along the cavity. 
         [0062]    In yet another further refinement, the pressure gradient includes a pressure gradient normal to the cavity. 
         [0063]    Embodiments include a gas turbine engine, comprising: a compressor system; a primary combustor; a turbine system including a hot section component, the hot section component including: a flowpath structure configured for operation in a gas turbine engine flowpath downstream of a primary combustor of the gas turbine engine, wherein the flowpath structure includes: a body having a tip portion and a hub portion, wherein the body includes means extending in a spanwise direction between the tip portion and the hub portion for receiving a reheat flow for distribution to the turbine system; and means for uniformly distributing the reheat flow from the means for receiving into the gas turbine engine flowpath. 
         [0064]    In a refinement, the means for uniformly distributing the reheat flow has a width in a flowpath direction that varies with location in the spanwise direction based on a pressure gradient at the location in the spanwise direction. 
         [0065]    In another refinement, the means for receiving has a cross-sectional area that varies with location in the spanwise direction based on a pressure gradient at the location in the spanwise direction. 
         [0066]    In yet another refinement, the means for uniformly distributing the reheat flow has a centerline that varies in location in a flowpath direction based on a pressure gradient at the location in the flowpath direction. 
         [0067]    In still another refinement, the body is an airfoil; and wherein the means for uniformly distributing the reheat flow is located on a suction side of the airfoil. 
         [0068]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.