Patent Publication Number: US-2023146097-A1

Title: Integrally formed flow distributor for fluid manifold

Description:
BACKGROUND 
     The present disclosure relates generally to fluid manifolds, and more specifically to flow distribution features (i.e., flow distributors) of fluid manifolds. 
     In general, fluid manifolds are designed to route one or more fluids between components in a fluid flow system. For example, heat exchangers typically include manifolds (i.e., headers) to route fluid flow into and out of the heat exchanger core. Heat exchanger cores have multiple flow paths, and the flow distribution throughout the flow paths can affect heat exchanger performance. Heat exchangers and other components may experience high velocity flow or may have asymmetries that affect flow distribution. Flow distribution features can be implemented in a fluid manifold to modify the flow distribution. 
     SUMMARY 
     In one example, a fluid manifold includes an inlet comprising an opening into an interior of the fluid manifold, an outlet end that is positioned opposite the inlet and that is in fluid communication with the inlet, a shroud extending between the inlet and the outlet end and surrounding a flow path of the fluid manifold, and a first flow distributor positioned within the interior of the fluid manifold. The first flow distributor includes a hollow body that extends in a downstream direction. The hollow body includes a first surface at a downstream side of the first flow distributor and a second surface at an upstream side of the first flow distributor, a central cavity defined by the second surface of the hollow body, and openings extending from the first surface to the second surface such that a fluid can pass from the central cavity through the openings to be directed within the fluid manifold. The first flow distributor and the fluid manifold are integrally formed. 
     In another example, a flow distributor for a fluid manifold includes a hollow body including a first surface at a downstream side of the flow distributor and a second surface at an upstream side of the flow distributor, a central cavity defined by the second surface of the hollow body, and openings extending from the first surface to the second surface such that a fluid can pass from the central cavity through the openings to be directed within the fluid manifold. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an isometric view of a fluid manifold. 
         FIG.  2    is a side view of the fluid manifold. 
         FIG.  3    is a top view of the fluid manifold showing a flow distributor. 
         FIG.  4    is an enlarged partial cross-sectional view of the fluid manifold taken at line  4 - 4  of  FIG.  3    showing details of the flow distributor. 
         FIG.  5    is a cross-sectional view of the fluid manifold and the flow distributor taken at line  5 - 5  of  FIG.  3   . 
         FIGS.  6 A- 6 D  are cross-sectional views of the fluid manifold taken at line  6 - 6  of  FIG.  2    showing alternative cross-sectional shapes of the flow distributor. 
         FIG.  7    is an isometric view of a fluid manifold with an angled inlet. 
         FIG.  8    is a cross-sectional view of the fluid manifold taken at plane  8 - 8  of  FIG.  7    showing a flow distributor. 
         FIG.  9    is a cross-sectional view of a fluid manifold including multiple flow distributors. 
         FIGS.  10 A- 10 E  are enlarged side views of a flow distributor showing alternative configurations of openings. 
     
    
    
     DETAILED DESCRIPTION 
     An integrally formed flow distributor and fluid manifold is described herein. In fluid flow systems, an inlet of a fluid manifold may be positioned at a center of the manifold so that fluid flow exiting the manifold is as distributed (i.e., uniform) as possible. However, this may not be achievable in many applications. Moreover, even when the inlet is aligned with the manifold the fluid flow may be a high velocity flow that does not spread out adequately in the relatively short distance to an outlet end of the manifold. The manifold can also have asymmetries and experience high velocity flow in combination. In traditional applications, a flow distributor can be implemented in the manifold to achieve improved flow distribution, but this can introduce undesired additional manufacturing steps. For example, the traditional manifold and flow distributor may be machined separately and attached by welding. Additionally, the design of a traditionally manufactured flow distributor could be limited by traditional machining requirements (e.g., tooling paths, etc.) such that variations of the flow distributor geometry can be difficult, impossible, or cost prohibitive to manufacture. The integrally formed flow distributor described herein can reduce the need for additional manufacturing steps and can more effectively optimize flow distribution within the manifold. The integrally formed flow distributor is described below with reference to  FIGS.  1 - 10 E . 
       FIGS.  1 - 6 D  will be discussed together.  FIG.  1    is an isometric view of fluid manifold  10 .  FIG.  2    is a side view of fluid manifold  10 .  FIG.  3    is a top view of fluid manifold  10  showing flow distributor  12 .  FIG.  4    is an enlarged partial cross-sectional view of fluid manifold  10  taken at line  4 - 4  of  FIG.  3    showing details of flow distributor  12 .  FIG.  5    is a cross-sectional view of fluid manifold  10  and flow distributor  12  taken at line  5 - 5  of  FIG.  3   .  FIGS.  6 A- 6 D  are cross-sectional views of fluid manifold  10  taken at line  6 - 6  of  FIG.  2    showing alternative cross-sectional shapes of flow distributors  12 A- 12 D. 
     Manifold  10  includes flow distributor  12 , shroud  14 , inlet  16 , and outlet end  18 . Shroud  14  includes exterior surface  20 , interior surface  22 , interior passageway (i.e., cavity)  23 , and floor  24 . Flow distributor  12  includes body  26 , first surface  28  (i.e., downstream surface  28 ), second surface  30  (i.e., upstream surface  30 ), openings  32 , top opening  33 , and central cavity  34 . Flow distributor  12  defines longitudinal axis L 1 . Inlet  16  includes primary channel  36  and connection portion  38 . 
     Inlet  16  forms an opening into the fluid system of manifold  10 . Inlet  16  is positioned at a first, or upstream, end of manifold  10  that is opposite outlet end  18 . As shown in  FIG.  5   , primary channel  36  of inlet  16  is a channel or passageway extending from the opening of inlet  16  into an interior of manifold  10 . Primary channel  36  extends within manifold  10  to floor  24  of shroud  14 . Primary channel  36  can have a circular or other cross-sectional area. 
     Inlet  16  can further include connection portion  38  adjacent or near the opening. Connection portion  38  is a portion of inlet  16  where manifold  10  can be connected to another component(s) or duct. Though connection portion  38  is illustrated in  FIG.  5    as threads in primary channel  36 , it should be understood that other suitable connection means are possible. 
     Shroud  14  is a main body portion of manifold  10 . Shroud  14  extends between inlet  16  and outlet end  18 . Moreover, shroud  14  can be continuous with inlet  16  and outlet end  18 . Shroud  14  surrounds a portion of a flow path of manifold  10 . Exterior surface  20  of shroud  14  extends from inlet  16  to outlet end  18  and is at an exterior of shroud  14 . Interior surface  22  of shroud  14  extends from inlet  16  to outlet end  18  and is at an interior of shroud  14 . Exterior surface  20  and interior surface  22  meet at inlet  16  and at outlet end  18 . 
     Interior surface  22 , including floor  24 , defines interior passageway  23  within shroud  14 . Interior passageway  23  is a passageway or cavity within shroud  14  that extends from primary channel  36  to outlet end  18 . As such, primary channel  36  of inlet  16  is a first, or upstream, passageway that is fluidly connected to and continuous with interior passageway  23 . As described above, primary channel  36  extends within manifold  10  to floor  24  of shroud  14 . At floor  24 , a cross-sectional area of interior passageway  23  can expand radially outward from the cross-sectional area of primary channel  36 . In other words, interior passageway  23  can be tapered toward floor  24  from outlet end  18 . More generally, interior passageway  23  can have a larger cross-sectional area than the cross-sectional area of primary channel  36 . 
     As shown in  FIGS.  1 - 5   , shroud  14  can be generally bell-shaped to accommodate interior passageway  23  and any interior components contained within shroud  14  (e.g., flow distributor  12 ). However, it should be understood that a three-dimensional shape of shroud  14  can be any suitable shape for accommodating interior passageway  23  and any interior components. Furthermore, the three-dimensional shape of shroud  14  can also depend on a geometry of a downstream component that is connected to outlet end  18 . Walls of shroud  14  (formed by exterior surface  20  and interior surface  22 ) can be partially or entirely curved or contoured or can be partially or entirely straight. 
     Additionally, as is most easily viewed in  FIGS.  2 ,  3 , and  5   , shroud  14  (and portions of interior passageway  23 ) may be asymmetric about longitudinal axis L 1  of flow distributor  12  and inlet  16 . For example, a portion of interior passageway  23  that is shown on the right side (as viewed) of longitudinal axis L 1  in  FIG.  5    can be larger than a portion of interior passageway  23  that is shown on the left side (as viewed) of longitudinal axis L 1  in  FIG.  5   . In other examples, shroud  14  and portions of interior passageway  23  can have other asymmetries about longitudinal axis L 1 . In yet other examples, shroud  14  and interior passageway  23  can be symmetric about longitudinal axis L 1 . 
     Flow distributor  12  is positioned within shroud  14  in interior passageway  23 . Specifically, flow distributor  12  extends from and is continuous with interior surface  22  at floor  24 . Flow distributor  12  extends in a downstream direction from floor  24 . First surface  28  is at an exterior of flow distributor  12 . First surface  28  is also at a downstream side of flow distributor  12 . Second surface  30  is at an interior of flow distributor  12 . Second surface  30  is also at an upstream side of flow distributor  12 . Each of first surface  28  and second surface  30  can be continuous with interior surface  22 . First surface  28  and second surface  30  meet at or along edges of openings  32 . In some examples (e.g., as shown in  FIGS.  3 - 5   ), first surface  28  and second surface  30  also meet at an edge of top opening  33 . Flow distributor  12  can be positioned such that longitudinal axis L 1  of flow distributor  12  is aligned (i.e., the same) as a longitudinal axis of inlet  16 . 
     Body  26  is a hollow, main portion of flow distributor  12  that extends or protrudes from floor  24  in a downstream direction with respect to a flow path of manifold  10 . Body  26  is defined by first surface  28  and second surface  30 . In some examples, body  26  can be generally dome-shaped (i.e., domed). In other examples, body  26  can be conical or frustoconical. As such, body  26  can be wider adjacent to floor  24  and tapered toward an opposite or top end (e.g., at top opening  33 ) of flow distributor  12 . In yet other examples, body  26  is not tapered and can instead have a generally cylindrical shape. 
     Referring now to  FIGS.  6 A- 6 D , the cross-sectional geometry of flow distributor  12  will be described in greater detail. Flow distributors  12 A- 12 D are examples of flow distributor  12  with different cross-sectional shapes. For example, as shown in  FIG.  6 A , flow distributor  12 A has a circular cross-sectional area. As shown in  FIG.  6 B , flow distributor  12 B has an oval or oblong cross-sectional area. As shown in  FIG.  6 C , flow distributor  12 C has a pentagonal cross-sectional area. As shown in  FIG.  6 D , flow distributor  12 D has a hexagonal cross-sectional area. It should be understood that other examples of flow distributor  12  can have other cross-sectional areas, such as other polygonal, arcuate, or even irregular shapes. In yet other examples, a cross-sectional shape of flow distributor  12  can change along longitudinal axis L 1  of flow distributor  12 . 
     Referring again to  FIGS.  4 - 5   , second surface  30  defines central cavity  34  within body  26  of flow distributor  12 . Thus, body  26  is hollow and surrounds central cavity  34 . Central cavity  34  is fluidly connected to and continuous with primary channel  36  and interior passageway  23 . 
     As will be described in greater detail below with respect to  FIGS.  10 A- 10 E , openings  32  are arranged on flow distributor  12 . Openings  32  extend from first surface  28  to second surface  30  such that central cavity  34  is in fluid communication with interior passage  23  (i.e., downstream of flow distributor  12 ). In some examples (e.g., as shown in  FIGS.  3 - 5   ), flow distributor  12  includes top opening  33  at the top end of flow distributor  12 . In other examples, top opening  33  may not be present. Like openings  32 , top opening  33  extends from first surface  28  to second surface  30 . For example, top opening  33  can be positioned centrally at the top end. Top opening  33  can also be larger in size than other openings  32 . It should be understood, however, that top opening  33  can have any suitable shape, size, and arrangement (i.e., positioning) on flow distributor  12 . 
     Outlet end  18  of manifold  10  forms a second, or downstream, end of manifold  10  that is opposite inlet  16 . Like inlet  16 , outlet end  18  forms an opening into the fluid system of manifold  10 . Because interior passageway  23  extends from primary channel  36  of inlet  16  to outlet end  18 , outlet end  18  is in fluid communication with inlet  16 . Manifold  10  can connect to another component or components at outlet end  18 . 
     In operation, inlet  16  of manifold  10  is configured to receive a fluid (not shown) from another component(s) or duct. The fluid can be any type of fluid, including air, water, lubricant, fuel, or another fluid. The other component or duct from which fluid is delivered to manifold  10  can be connected to manifold  10  at connection portion  38  of inlet  16 . 
     A flow path of manifold  10  (i.e., the path along which the fluid flows within manifold  10 ) can include primary channel  36  of inlet  16 , central cavity  34  of flow distributor  12 , and interior passageway  23  within shroud  14 . In sequential order, the fluid flows from inlet  16  through flow distributor  12  to outlet end  18 . More specifically, the fluid entering manifold  10  at inlet  16  is channeled through primary channel  36  to central cavity  34  of flow distributor  12 . The fluid encounters upstream surface  30  of flow distributor  12  then passes through openings  32  and top opening  33  in a direction from upstream surface  30  to downstream surface  28 . As such, fluid flowing through flow distributor  12  is distributed within interior passage  23  (i.e., downstream of flow distributor  12 ). The fluid can be directed generally toward outlet end  18 . From outlet end  18 , the fluid can be discharged from manifold  10  into another component or components. For example, manifold  10  can be configured as a header for a heat exchanger and the fluid can flow from outlet end  18  into channels of a heat exchanger core. In other examples, manifold  10  can be implemented with any component or components that would benefit from flow distribution features for flow balance. 
     Manifold  10  and flow distributor  12  can be integrally formed. To be integrally formed, manifold  10  and its component parts can be formed partially or entirely by additive manufacturing. For metal components (e.g., nickel-based superalloys, aluminum, titanium, etc.) exemplary additive manufacturing processes include powder bed fusion techniques such as direct metal laser sintering (DMLS), laser net shape manufacturing (LNSM), electron beam manufacturing (EBM), to name a few, non-limiting examples. For polymer or plastic components, stereolithography (SLA) can be used. Additive manufacturing is particularly useful in obtaining unique geometries and for reducing the need for welds or other attachments (e.g., between a manifold and flow distributor). However, it should be understood that other suitable manufacturing processes can be used. Additionally, post-manufacture machining techniques can be utilized to form features of manifold  10 , such as threads of connection portion  38 . In other examples, features like connection portion  38  can be integrally formed with additively manufactured manifold  10 . 
     During an additive manufacturing process, manifold  10  can be formed layer by layer to achieve varied dimensions (e.g., cross-sectional area, wall thicknesses, curvature, etc.) and complex internal passages and/or components. Each additively manufactured layer creates a new horizontal build plane to which a subsequent layer of manifold  10  is fused. That is, the build plane for the additive manufacturing process remains horizontal but shifts vertically by defined increments (e.g., one micrometer, one hundredth of a millimeter, one tenth of a millimeter, a millimeter, or other distances) as manufacturing proceeds. Therefore, manifold  10  can be additively manufactured as a single, monolithic unit or part.  FIGS.  1 - 6 D  show manifold  10  already fully manufactured. 
     Additive manufacturing techniques allow manifold  10  to be integrally formed as a single part with flow distributor  12 . Moreover, manifold  10  including integrally formed flow distributor  12  can be additively manufactured along with a larger component, such as a heat exchanger. That is, a heat exchanger or other component can be additively manufactured to include integrally formed manifold  10  and flow distributor  12  such that the heat exchanger or other component including manifold  10  and flow distributor  12  is a single, monolithic part. The integral formation of manifold  10  with flow distributor  12  by additive manufacturing allows for the consolidation of parts and can reduce or eliminate the need for any post-process machining that is typically required with traditionally manufactured components. 
     In general, additive manufacturing permits construction of a higher fidelity part driven by computational fluid dynamics (CFD) analysis to distribute fluid flow accurately and evenly. More specifically, additive manufacturing permits the creation of more complex or organic geometries that would otherwise be difficult or impossible to manufacture through traditional methods. The overall flow distribution design (i.e., design of integral flow distributor  12 ) can be determined and/or modified based on CFD analyses and simulations. The size, shape, and/or arrangement of openings  32 , top opening  33 , and/or flow distributor  12  can be optimized through CFD analyses. It is advantageous for optimization to have more options and greater flexibility in possible flow distribution design geometries. 
     The three-dimensional size, shape, and/or positioning of flow distributor  12  can be more accurately tailored to redistribute fluid flow based on desired flow distribution characteristics. Additionally, or alternatively, the size, shape, and/or arrangement of openings  32  and top opening  33  can vary throughout flow distributor  12  depending on the desired flow distribution characteristics. Variations in the size, shape, and/or arrangement of openings  32  and top opening  33  can allow for improved flow distribution in a variety of fluid manifold configurations. Flow distributor  12  having variations in the size, shape, and/or arrangement of openings  32  and top opening  33  presents an advantage over traditional flow distributors that are limited to having uniformly sized and shaped openings because the present design can be more accurately tailored to redistribute flow based on inlet conditions of a particular fluid manifold or of a particular fluid (e.g., fluid type, flow velocity, inlet orientation, manifold size, etc.). 
       FIGS.  7  and  8    will be discussed together.  FIG.  7    is an isometric view of fluid manifold  100  with angled inlet  116 .  FIG.  8    is a cross-sectional view of fluid manifold  100  taken at plane  8 - 8  of  FIG.  7    showing angled flow distributor  112 . 
     Manifold  100  includes angled flow distributor  112 , shroud  114 , angled inlet  116 , and outlet end  118 . Shroud  114  includes exterior surface  120 , interior surface  122 , interior passageway  123 , and floor  124 . Angled flow distributor  112  includes body  126 , first surface  128 , second surface  130 , openings  132 , top opening  133 , and central cavity  134 . Angled flow distributor  112  defines longitudinal axis L 2 . Angled inlet  116  includes primary channel  136  and connection portion  138  and defines longitudinal axis L 3 . Manifold  100  has essentially the same structure and function as described above with reference to manifold  10  in  FIGS.  1 - 6 D , except manifold  100  includes angled flow distributor  112  and angled inlet  116  rather than an aligned flow distributor and inlet (e.g., as shown in  FIGS.  1 - 6 D ). 
     As shown in  FIG.  8   , inlet  116  can have longitudinal axis L 3  which is not aligned with longitudinal axis L 2  of flow distributor  112 . That is, longitudinal axis L 2  and longitudinal axis L 3  can intersect to form a non-zero angle. The non-zero angle can be any non-zero angle. Further, the non-zero angle can be based on conditions of inlet  116 . For example, inlet  116  can be angled with respect to flow distributor  112  due to a geometry of another component(s) or duct that is connected to manifold  100  at inlet  116 . Inlet  116  may be positioned at an angle suitable to accommodate the connected component(s). 
     Fluid flowing within manifold  100  flows from angled inlet  116  through angled flow distributor  112  to outlet end  118 . More specifically, the fluid entering manifold  100  at inlet  116  is channeled through primary channel  136  to central cavity  134  of flow distributor  112 . Because longitudinal axis L 2  of flow distributor  112  and longitudinal axis L 3  of inlet  116  are not aligned, the fluid flow is redirected (i.e., turns) as it passes from primary channel  136  into central cavity  134  (as indicated by arrows in  FIG.  8   ). The fluid encounters upstream surface  130  of flow distributor  112  then passes through openings  132  and top opening  133  in a direction from upstream surface  130  to downstream surface  128 . As such, fluid flowing through flow distributor  112  is distributed within interior passage  123  (i.e., downstream of flow distributor  112 ). The fluid can be directed generally toward outlet end  118 . From outlet end  118 , the fluid can be discharged from manifold  100  into another component or components. 
     Manifold  100  and flow distributor  112  can be integrally formed. To be integrally formed, manifold  100  and its component parts can be formed partially or entirely by additive manufacturing. For metal components (e.g., nickel-based superalloys, aluminum, titanium, etc.) exemplary additive manufacturing processes include powder bed fusion techniques such as direct metal laser sintering (DMLS), laser net shape manufacturing (LNSM), electron beam manufacturing (EBM), to name a few, non-limiting examples. For polymer or plastic components, stereolithography (SLA) can be used. Additive manufacturing is particularly useful in obtaining unique geometries and for reducing the need for welds or other attachments (e.g., between a manifold and flow distributor). However, it should be understood that other suitable manufacturing processes can be used. Additionally, post-manufacture machining techniques can be utilized to form features of manifold  100 , such as threads of connection portion  138 . In other examples, features like connection portion  138  can be integrally formed with additively manufactured manifold  100 . 
     During an additive manufacturing process, manifold  100  can be formed layer by layer to achieve varied dimensions (e.g., cross-sectional area, wall thicknesses, curvature, etc.) and complex internal passages and/or components. Each additively manufactured layer creates a new horizontal build plane to which a subsequent layer of manifold  100  is fused. That is, the build plane for the additive manufacturing process remains horizontal but shifts vertically by defined increments (e.g., one micrometer, one hundredth of a millimeter, one tenth of a millimeter, a millimeter, or other distances) as manufacturing proceeds. Therefore, manifold  100  can be additively manufactured as a single, monolithic unit or part.  FIGS.  7 - 8    show manifold  100  already fully manufactured. 
     Additive manufacturing techniques allow manifold  100  to be integrally formed as a single part with flow distributor  112 . Moreover, manifold  100  including integrally formed flow distributor  112  can be additively manufactured along with a larger component, such as a heat exchanger. That is, a heat exchanger or other component can be additively manufactured to include integrally formed manifold  100  and flow distributor  112  such that the heat exchanger or other component including manifold  100  and flow distributor  112  is a single, monolithic part. The integral formation of manifold  100  with flow distributor  112  by additive manufacturing allows for the consolidation of parts and can reduce or eliminate the need for any post-process machining that is typically required with traditionally manufactured components. 
     In general, additive manufacturing permits construction of a higher fidelity part driven by computational fluid dynamics (CFD) analysis to distribute fluid flow accurately and evenly. More specifically, additive manufacturing permits the creation of more complex or organic geometries that would otherwise be difficult or impossible to manufacture through traditional methods. The overall flow distribution design (i.e., design of integral flow distributor  112 ) can be determined and/or modified based on CFD analyses and simulations. The size, shape, and/or arrangement of openings  132 , top opening  133 , and/or flow distributor  112  can be optimized through CFD analyses. It is advantageous for optimization to have more options and greater flexibility in possible flow distribution design geometries. 
     The three-dimensional size, shape, and/or positioning of angled flow distributor  112  can be more accurately tailored to redistribute fluid flow based on desired flow distribution characteristics. Specifically, the non-zero angle between longitudinal axis L 2  of flow distributor  112  and longitudinal axis L 3  of inlet  116  allows flow distributor  112  to improve flow distribution in configurations where the inlet is not aligned with a center of the manifold. Therefore, flow distributor  112  enables the integral construction and optimization benefits described herein to be implemented in a greater variety of fluid flow systems. 
     Additionally, or alternatively, the size, shape, and/or arrangement of openings  132  and top opening  133  can vary throughout flow distributor  112  depending on the desired flow distribution characteristics. Variations in the size, shape, and/or arrangement of openings  132  and top opening  133  can allow for improved flow distribution in a variety of fluid manifold configurations. Flow distributor  112  having variations in the size, shape, and/or arrangement of openings  132  and top opening  133  presents an advantage over traditional flow distributors that are limited to having uniformly sized and shaped openings because the present design can be more accurately tailored to redistribute flow based on inlet conditions of a particular fluid manifold or of a particular fluid (e.g., fluid type, flow velocity, inlet orientation, manifold size, etc.). 
       FIG.  9    is a cross-sectional view of fluid manifold  200  including multiple flow distributors  212 . Manifold  200  includes first flow distributor  212 A, second flow distributor  212 B, shroud  214 , inlet  216 , and outlet end  218 . Shroud  214  includes exterior surface  220 , interior surface  222 , interior passageway  223 , floor  224 , and intermediate passageway  225 . First and second flow distributors  212 A and  212 B include body  226 A and  226 B, first surface  228 A and  228 B, second surface  230 A and  230 B, openings  232 A and  232 B, top opening  233 A and  233 B, and central cavity  234 A and  234 B, respectively. Inlet  216  includes primary channel  236  and connection portion  238 . Manifold  200  has essentially the same structure and function as described above with reference to manifold  10  in  FIGS.  1 - 6 D , except manifold  200  additionally includes multiple flow distributors  212 A- 212 B and intermediate passageway  225 . Each of flow distributors  212 A and  212 B includes essentially the same components, which are labeled respectively with A or B, but which will be referred to generally herein by the shared reference number. For example, body  226  refers collectively to body  226 A and body  226 B. 
     Intermediate passageway  225  is an additional passageway or cavity within shroud  214  that is upstream of floor  224  and bounded by interior surface  222 . Intermediate passageway  225  extends between primary channel  236  of inlet  216  and floor  224  of shroud  214 . As such, intermediate passageway  225  is fluidly connected to and continuous with primary channel  236 . Intermediate passageway  225  separates floor  224  from an interior end of primary channel  236  such that multiple flow distributors  212  can be positioned on floor  224 . A distance from the interior end of primary channel  236  to floor  224  (i.e., a height of intermediate passageway  225 ) can depend on a number, size, and/or arrangement of flow distributors  212 . Thus, intermediate passageway  225  can be taller or shorter than the example shown in  FIG.  9   . 
     Multiple flow distributors  212  are positioned within shroud  214  in interior passageway  223 . As shown in  FIG.  9   , manifold  200  can include two flow distributors  212 . In other examples, manifold  200  can include more than two flow distributors  212 . In yet other examples, manifold  200  can include any suitable number of flow distributors  212 . 
     Flow distributors  212  extend from and are continuous with interior surface  222  at floor  224 . Flow distributors  212  extend in a downstream direction from floor  224 . Flow distributors  212  can be directly adjacent one another or spaced apart on floor  224 . Flow distributors  212  can also have parallel longitudinal axes (e.g., as shown in  FIG.  9   ) or can be angled with respect to each other. Moreover, each of flow distributors  212  can have a similar size and shape (e.g., as shown in  FIG.  9   ) or can have different sizes and shapes. 
     Central cavities  234  of flow distributors  212  are fluidly connected to and continuous with intermediate passageway  225  and interior passageway  223 . Openings  232  extend from first surface  228  to second surface  230  of each flow distributor  212  such that central cavities  234  are in fluid communication with interior passage  223  (i.e., downstream of flow distributors  212 ). Each of flow distributors  212  can have a same or different configuration of openings  232 . 
     Fluid flowing within manifold  200  flows from inlet  216  through flow distributors  212  to outlet end  218 . More specifically, the fluid entering manifold  200  at inlet  216  is channeled through primary channel  236  to intermediate passageway  225 . From intermediate passageway  225 , fluid flows into central cavities  234  of flow distributors  212 . The fluid encounters upstream surfaces  230  of flow distributors  212  then passes through openings  232  and top opening  233  in a direction from upstream surfaces  230  to downstream surfaces  228 . As such, fluid flowing through flow distributors  212  is distributed within interior passageway  223  (i.e., downstream of flow distributors  212 ). The fluid can be directed generally toward outlet end  218 . From outlet end  218 , the fluid can be discharged from manifold  200  into another component or components. 
     Manifold  200  and flow distributors  212  can be integrally formed. To be integrally formed, manifold  200  and its component parts can be formed partially or entirely by additive manufacturing. For metal components (e.g., nickel-based superalloys, aluminum, titanium, etc.) exemplary additive manufacturing processes include powder bed fusion techniques such as direct metal laser sintering (DMLS), laser net shape manufacturing (LNSM), electron beam manufacturing (EBM), to name a few, non-limiting examples. For polymer or plastic components, stereolithography (SLA) can be used. Additive manufacturing is particularly useful in obtaining unique geometries and for reducing the need for welds or other attachments (e.g., between a manifold and flow distributor). However, it should be understood that other suitable manufacturing processes can be used. Additionally, post-manufacture machining techniques can be utilized to form features of manifold  200 , such as threads of connection portion  238 . In other examples, features like connection portion  238  can be integrally formed with additively manufactured manifold  200 . 
     During an additive manufacturing process, manifold  200  can be formed layer by layer to achieve varied dimensions (e.g., cross-sectional area, wall thicknesses, curvature, etc.) and complex internal passages and/or components. Each additively manufactured layer creates a new horizontal build plane to which a subsequent layer of manifold  200  is fused. That is, the build plane for the additive manufacturing process remains horizontal but shifts vertically by defined increments (e.g., one micrometer, one hundredth of a millimeter, one tenth of a millimeter, a millimeter, or other distances) as manufacturing proceeds. Therefore, manifold  200  can be additively manufactured as a single, monolithic unit or part.  FIG.  9    shows manifold  200  already fully manufactured. 
     Additive manufacturing techniques allow manifold  200  to be integrally formed as a single part with flow distributors  212 . Moreover, manifold  200  including integrally formed flow distributors  212  can be additively manufactured along with a larger component, such as a heat exchanger. That is, a heat exchanger or other component can be additively manufactured to include integrally formed manifold  200  and flow distributors  212  such that the heat exchanger or other component including manifold  200  and flow distributors  212  is a single, monolithic part. The integral formation of manifold  200  with flow distributors  212  by additive manufacturing allows for the consolidation of parts and can reduce or eliminate the need for any post-process machining that is typically required with traditionally manufactured components. 
     In general, additive manufacturing permits construction of a higher fidelity part driven by computational fluid dynamics (CFD) analysis to distribute fluid flow accurately and evenly. More specifically, additive manufacturing permits the creation of more complex or organic geometries that would otherwise be difficult or impossible to manufacture through traditional methods. The overall flow distribution design (i.e., design of integral flow distributors  212 ) can be determined and/or modified based on CFD analyses and simulations. The size, shape, and/or arrangement of openings  232 , top opening  233 , and/or flow distributors  212  can be optimized through CFD analyses. It is advantageous for optimization to have more options and greater flexibility in possible flow distribution design geometries. 
     The three-dimensional size, shape, and/or positioning of multiple flow distributors  212  can be more accurately tailored to redistribute fluid flow based on desired flow distribution characteristics. Specifically, manifold  200  including multiple flow distributors  212  can improve flow distribution in configurations where the manifold is sufficiently large (e.g., has a large interior passageway  223 ) such that fluid flow may not be adequately distributed by a single flow distributor. Therefore, flow distributors  212  enable the integral construction and optimization benefits described herein to be implemented in a greater variety of fluid flow systems. 
     Additionally, or alternatively, the size, shape, and/or arrangement of openings  232  and top opening  233  can vary throughout flow distributors  212  depending on the desired flow distribution characteristics. Variations in the size, shape, and/or arrangement of openings  232  and top opening  233  can allow for improved flow distribution in a variety of fluid manifold configurations. Flow distributors  212  having variations in the size, shape, and/or arrangement of openings  232  and top opening  233  present an advantage over traditional flow distributors that are limited to having uniformly sized and shaped openings because the present design can be more accurately tailored to redistribute flow based on inlet conditions of a particular fluid manifold or of a particular fluid (e.g., fluid type, flow velocity, inlet orientation, manifold size, etc.). 
       FIGS.  10 A- 10 E  are enlarged side views of flow distributors  300 A- 300 E showing alternative configurations of openings  302 A- 302 E. Flow distributors  300 A- 300 E include openings  302 A- 302 E, respectively. Openings  302 B are arranged in rows  304 B. Flow distributors  300 A- 300 E with openings  302 A- 302 E are examples of flow distributor  12  and openings  32  ( FIGS.  1 - 6 D ), flow distributor  112  and openings  132  ( FIGS.  7 - 8   ), or flow distributors  212  and openings  232  ( FIG.  9   ) in various configurations. 
     Generally, openings  302 A- 302 E of respective flow distributors  300 A- 300 B can be any suitable shape. For example, as shown in  FIG.  10 A , flow distributor  300 A has rounded, tear drop shaped openings  302 A. As shown in  FIG.  10 C , flow distributor  300 C has triangular openings  302 C. As shown in  FIG.  10 D , flow distributor  300 D has rhombus shaped openings  302 D. As shown in  FIG.  10 E , flow distributor  300 E has star shaped openings  302 E. It should be understood that other examples of flow distributors  300 A- 300 E can have differently shaped openings  302 A- 302 E, such as other polygonal, arcuate, or even irregular shapes. 
     Referring now to  FIGS.  10 A and  10 B , the size and shape of openings  302 A and  302 B varies throughout flow distributors  300 A and  300 B, respectively. As shown in  FIG.  10 A , the size and shape of openings  302 A varies along a longitudinal axis of flow distributor  300 A. Specifically, openings  302 A are larger and wider at a first end of flow distributor  300 A (e.g., an end that is continuous with floor  24  of manifold  10 ) and progressively smaller and narrower towards a longitudinally opposite second end. In other examples, this relationship can be reversed such that openings  302 A are smaller and narrower at the first end of flow distributor  300 A and progressively larger and wider towards the longitudinally opposite second end. 
     As shown in  FIG.  10 B , openings  302 B can be arranged in rows  304 B around flow distributor  300 B. The size and shape of openings  302 B varies laterally along rows  304 B. Specifically, openings  302 B are larger and wider at a first side of flow distributor  300 B and progressively smaller and narrower towards a laterally opposite second side. In other examples, this relationship can be reversed such that openings  302 B are smaller and narrower at the first side of flow distributor  300 B and progressively larger and wider towards the laterally opposite second side. 
     In yet other examples, the size and/or shape of openings  302 A and  302 B can vary in clusters or sporadically throughout flow distributors  300 A and  300 B, rather than the progressive variation shown in  FIGS.  10 A and  10 B . As shown in  FIGS.  10 C- 10 E , the size and shape of openings  302 C- 302 E can also be uniform throughout flow distributors  300 C- 300 E. 
     A density of openings  302 A- 302 E also varies throughout flow distributors  300 A- 300 E, respectively. As shown in each of  FIGS.  10 A- 10 E , openings  302 A- 302 E are more densely arranged at a first end of flow distributors  300 A- 300 E. Openings  302 A- 302 E become progressively less dense towards a longitudinally opposite second end. In other examples, this relationship can be reversed such that openings  302 A- 302 E are less densely arranged at the first end of flow distributors  300 A- 300 E and progressively denser towards the longitudinally opposite second end. 
     In yet other examples, the density of openings  302 A- 302 E can vary in clusters or sporadically throughout flow distributors  300 A- 300 E, rather than the progressive variation shown in  FIGS.  10 A- 10 E . In further examples, the density of openings  302 A- 302 E can be uniform throughout flow distributors  300 A- 300 E. 
     When flow distributors  300 A- 300 E are implemented in a fluid manifold (e.g., manifold  10  of  FIGS.  1 - 6 D , manifold  100  of  FIGS.  7 - 8   , or manifold  200  of  FIG.  9   ), fluid flowing through the manifold passes through openings  302 A- 302 E. The size, shape, and arrangement of openings  302 A- 302 E can modify the flow characteristics of the fluid as it passes through flow distributors  300 A- 300 E to redistribute or direct the flow. For example, there can be increased flow through a portion of flow distributor  302 B where the size and/or density of openings  302 B is increased. Likewise, there can be decreased flow through a portion of flow distributor  302 B where the size and/or density of openings  302 B is decreased. Fluid flow is distributed (e.g., within a fluid manifold) after passing through respective openings  302 A- 302 E of flow distributors  300 A- 300 E. 
     In general, additive manufacturing permits construction of a higher fidelity part driven by computational fluid dynamics (CFD) analysis to distribute fluid flow accurately and evenly. More specifically, additive manufacturing permits the creation of more complex or organic geometries that would otherwise be difficult or impossible to manufacture through traditional methods. For example, certain sizes, shapes, and arrangements of openings  302 A- 302 E may be possible with additive manufacturing but not feasible with traditional manufacturing techniques. The overall flow distribution design (i.e., design of flow distributors  300 A- 300 E) can be determined and/or modified based on CFD analyses and simulations. The size, shape, and/or arrangement of openings  302 A- 302 E and of flow distributors  300 A- 300 E can be optimized through CFD analyses. It is advantageous for optimization to have more options and greater flexibility in possible flow distribution design geometries. 
     The size, shape, and/or arrangement of openings  302 A- 302 E can vary throughout flow distributors  300 A- 300 E depending on the desired flow distribution characteristics. Variations in the size, shape, and/or arrangement of openings  302 A- 302 E can allow for improved flow distribution in a variety of fluid manifold configurations. Flow distributors  300 A- 300 E having variations in the size, shape, and/or arrangement of openings  302 A- 302 E present an advantage over traditional flow distributors that are limited to having uniformly sized and shaped openings because the present design can be more accurately tailored to redistribute flow based on inlet conditions of a particular fluid manifold or of a particular fluid (e.g., fluid type, flow velocity, inlet orientation, manifold size, etc.). 
     Discussion of Possible Embodiments 
     The following are non-exclusive descriptions of possible embodiments of the present invention. 
     A fluid manifold includes an inlet comprising an opening into an interior of the fluid manifold, an outlet end that is positioned opposite the inlet and that is in fluid communication with the inlet, a shroud extending between the inlet and the outlet end and surrounding a flow path of the fluid manifold, and a first flow distributor positioned within the interior of the fluid manifold. The first flow distributor includes a hollow body that extends in a downstream direction. The hollow body includes a first surface at a downstream side of the first flow distributor and a second surface at an upstream side of the first flow distributor, a central cavity defined by the second surface of the hollow body, and openings extending from the first surface to the second surface such that a fluid can pass from the central cavity through the openings to be directed within the fluid manifold. The first flow distributor and the fluid manifold are integrally formed. 
     The fluid manifold of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components: 
     The shroud can include an exterior surface and an interior surface, the interior surface can define the flow path of the fluid manifold, and the first flow distributor can be continuous with the interior surface of the shroud. 
     A longitudinal axis of the first flow distributor can form a non-zero angle with a longitudinal axis of the inlet. 
     The shroud can be asymmetric about a longitudinal axis of the first flow distributor. 
     The fluid manifold can include a second flow distributor positioned within the interior of the fluid manifold. 
     The fluid manifold can include an intermediate fluid passageway positioned between the inlet and the first and second flow distributors. 
     A shape of the openings can vary throughout the first flow distributor. 
     The openings can be arranged in rows and the shape of the openings can vary laterally along the rows. 
     The shape of the openings can vary along a longitudinal axis of the first flow distributor. 
     A size of the openings on a first side of the first flow distributor can be greater than a size of the openings on a laterally opposite second side of the first flow distributor. 
     A size of the openings can vary throughout the first flow distributor. 
     The openings can be arranged in rows and the size of the openings can vary laterally along the rows. 
     The size of the openings can vary along a longitudinal axis of the first flow distributor. 
     A density of the openings can vary throughout the first flow distributor. 
     The first flow distributor can have a circular cross-sectional area. 
     The openings can be tear drop shaped. 
     The openings can be rounded. 
     At least one of a size, a shape, and an arrangement of the openings can be determined based on a CFD analysis to optimize flow distribution in the fluid manifold. 
     A flow distributor for a fluid manifold includes a hollow body including a first surface at a downstream side of the flow distributor and a second surface at an upstream side of the flow distributor, a central cavity defined by the second surface of the hollow body, and openings extending from the first surface to the second surface such that a fluid can pass from the central cavity through the openings to be directed within the fluid manifold. 
     The flow distributor of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components: 
     At least one of a size, a shape, and a density of the openings can vary throughout the flow distributor. 
     While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.