Patent Publication Number: US-2023160641-A1

Title: Aircraft Heat Exchanger Panel Attachment

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a divisional application of U.S. patent application Ser. No. 17/139,180, filed Dec. 31, 2020, and entitled “Aircraft Heat Exchanger Panel Attachment” which claims benefit of U.S. Patent Application No. 62/971,522, filed Feb. 7, 2020, and entitled an “Aircraft Heat Exchanger Panel Attachment”, the disclosure of which is incorporated by reference herein in its entirety as if set forth at length. 
    
    
     BACKGROUND 
     The disclosure relates to gas turbine engine heat exchangers. More particularly, the disclosure relates to air-to-air heat exchangers. 
     Gas turbine engines (used in propulsion and power applications and broadly inclusive of turbojets, turboprops, turbofans, turboshafts, industrial gas turbines, and the like) include a variety of heat exchangers. Examples of gas turbine engine heat exchangers are found in: United States Patent Application Publication 20190170445A1 (the &#39;445 publication), McCaffrey, Jun. 6, 2019, “HIGH TEMPERATURE PLATE FIN HEAT EXCHANGER”; United States Patent Application Publication 20190170455A1 (the &#39;455 publication), McCaffrey, Jun. 6, 2019, “HEAT EXCHANGER BELL MOUTH INLET”; and United States Patent Application Publication 20190212074A1 (the &#39;074 publication), Lockwood et al., Jul. 11, 2019, “METHOD FOR MANUFACTURING A CURVED HEAT EXCHANGER USING WEDGE SHAPED SEGMENTS”, the disclosures of which three publications are incorporated by reference in their entireties herein as if set forth at length. 
     An exemplary positioning of such a heat exchanger provides for the transfer of thermal energy from a flow (heat donor flow) diverted from an engine core flow to a bypass flow (heat recipient flow). For example, air is often diverted from the compressor for purposes such as cooling the turbine or aircraft systems. However, the act of compression heats the air and reduces its cooling effectiveness. Accordingly, the diverted air may be cooled in the heat exchanger to render it more suitable for cooling or other purposes. One particular example draws the heat donor airflow from a diffuser case downstream of the last compressor stage upstream of the combustor. This donor flow transfers heat to a recipient flow which is a portion of the bypass flow. To this end, the heat exchanger may be positioned within a fan duct or other bypass duct. The cooled donor flow is then returned to the engine core (e.g., radially inward through struts) to pass radially inward of the gas path and then be passed rearward for turbine section cooling including the cooling of turbine blades and vanes. The heat exchanger may conform to the bypass duct. The bypass duct is generally annular. Thus, the heat exchanger may occupy a sector of the annulus up to the full annulus. 
     Other heat exchangers may carry different fluids and be in different locations. For example, instead of rejecting heat to an air flow in a bypass duct, other heat exchangers may absorb heat from a core flow (e.g., as in recuperator use). 
     U.S. Pat. No. 10,100,740 (the &#39;740 patent, the disclosure of which is incorporated by reference in its entirety herein as if set forth at length), to Thomas, Oct. 16, 2018, “Curved plate/fin heater exchanger”, shows attachment of a square wave form fin array to the side of a heat exchanger plate body. For radially-extending plates in a radial array, the wave amplitude progressively increases to accommodate a similar increase in inter-plate spacing. 
     SUMMARY 
     One aspect of the disclosure involves a heat exchanger for providing thermal energy transfer between a first flow along a first flowpath and a second flow along a second flowpath. The heat exchanger has: at least one plate bank and a manifold having an inlet plenum and an outlet plenum. The plate bank has a plurality of plates, each plate having: a first face and a second face opposite the first face; a leading edge along the second flowpath and a trailing edge along the second flowpath; a proximal edge having at least one inlet port along the first flowpath and at least one outlet port along the first flowpath; and at least one passageway along the first flowpath. The manifold has a first face to which the plurality of plates are mounted along their respective proximal edges. The inlet plenum has at least one inlet port and at least one outlet port. The outlet plenum has at least one outlet port and at least one inlet port. The first flowpath passes from the at least one inlet port of the inlet plenum, through the at least one passageway of each of the plurality of plates, and through the at least one outlet port of the outlet plenum. For each plate, the manifold first face has a respective associated slot capturing a portion of the plate along the proximal edge thereof to prevent extraction of the plate normal to the manifold first face. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include said captured portion of the plate being a dovetail having tapering shoulders and a base. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include each plate having a mounting ear having an aperture. A respective threaded fastener extends through the aperture. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include each slot having a closed first end and an open second end. The fastener is proximate the second end. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the aperture being an open slot. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the fastener having a head flush or subflush to the manifold first face adjacent the slot. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include each slot having a closed first end and an open second end. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include each slot having a base. Each slot base has a first groove and a second groove. A first seal in the first groove seals the associated plate inlet port to a respective said inlet plenum outlet port. A second seal in the second groove seals the associated plate outlet port to a respective said outlet plenum inlet port. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include, for each plate of the plurality of plates, the at least one passageway comprising: an inlet plenum extending from the at least one inlet port of the plate; an outlet plenum extending to the at least one outlet port of the plate; and a plurality of legs fluidically in parallel between the inlet plenum and the outlet plenum. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include: one or more reinforcement walls in the inlet plenum; and/or one or more reinforcement walls in the outlet plenum. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the inlet plenum being adjacent the trailing edge and the outlet plenum being adjacent the leading edge. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include, in the at least one plate bank, the plates being parallel to each other. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include each plate further comprising an external fin array. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include respective external fin arrays connecting adjacent said plates. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include a gas turbine engine including the heat exchanger. 
     Another aspect of the disclosure involves a heat exchanger plate for providing heat transfer between a first flow along a first flowpath and a second flow along a second flowpath. The heat exchanger plate comprises: a first face and a second face opposite the first face; a leading edge along the second flowpath and a trailing edge along the second flowpath; a proximal edge having at least one inlet port along the first flowpath and at least one outlet port along the first flowpath; and at least one passageway along the first flowpath. The proximal edge is along a mounting rail (e.g., a thickened mounting rail such as a dovetail rail). 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the proximal edge extending from a first end to a second end. At the second end, the plate has an apertured mounting ear. 
     Another aspect of the disclosure involves a heat exchanger plate for providing heat transfer between a first flow along a first flowpath and a second flow along a second flowpath The heat exchanger plate comprises: a first face and a second face opposite the first face; a leading edge along the second flowpath and a trailing edge along the second flowpath; a proximal edge having at least one inlet port along the first flowpath and at least one outlet port along the first flowpath; and at least one passageway along the first flowpath. The proximal edge extends from a first end to a second end. At the second end, the plate has an apertured mounting ear. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include at the first end, the plate lacking an apertured mounting ear. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the aperture of the apertured mounting ear being an open-end slot. 
     Another aspect of the disclosure involves a heat exchanger manifold having: a first face having a plurality of plate mounting slots; an inlet plenum; and an outlet plenum. The inlet plenum has: at least one inlet port; and a plurality of outlet ports, each outlet port along a respective said slot. The outlet plenum has: at least one outlet port; and a plurality of inlet ports, each inlet port along a respective said slot. 
     A further embodiment of any of the foregoing embodiments may additionally and/or alternatively include the manifold being in a heat exchanger for providing thermal energy transfer between a first flow along a first flowpath and a second flow along a second flowpath. The heat exchanger further comprises: at least one plate bank comprising a plurality of plates. Each plate has: a first face and a second face opposite the first face; a leading edge along the second flowpath and a trailing edge along the second flowpath; a proximal edge, a portion along the proximal edge captured in having mounted to an associated said slot of the manifold first face to prevent extraction of the plate normal to the first face; and at least one passageway along the first flowpath. The first flowpath passes from the at least one inlet port of the inlet plenum, through the at least one passageway of each of the plurality of plates, and through the at least one outlet port of the outlet plenum. 
     Other aspects of the disclosure may involve methods for manufacturing and/or methods for using the heat exchanger of any of the foregoing embodiments. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view of a heat exchanger. 
         FIGS.  1 A and  1 B  are enlarged views of inter-panel spaces of the heat exchanger of  FIG.  1   . 
         FIG.  1 C  shows an alternate enlarged view of an inter-panel space. 
         FIG.  2    is a cutaway view of a panel portion of the heat exchanger of  FIG.  1    with lateral end walls cut away. 
         FIG.  3    is a cutaway plan view of the heat exchanger of  FIG.  1   . 
         FIG.  4    is a longitudinal sectional view of the heat exchanger taken along line  4 - 4  of  FIG.  3   . 
         FIG.  4 A  is an enlarged view of a plate rail end portion of the heat exchanger of  FIG.  4   . 
         FIG.  5    is a view of a plate of the heat exchanger. 
         FIG.  6    is a sectional view of a section of the heat exchanger taken along line  6 - 6  of  FIG.  4   . 
         FIG.  6 A  is an enlarged view of a plate-to-manifold junction of the heat exchanger of  FIG.  6   . 
         FIG.  7    is a cutaway view of the manifold of the heat exchanger section of  FIG.  2   . 
         FIG.  8    is a plan view of the manifold section of  FIG.  7   . 
         FIG.  9    is a cutaway view of the manifold along line  9 - 9  of  FIG.  4    with lateral end walls cut away. 
         FIG.  9 A  is an enlarged view of an end portion of the manifold of  FIG.  9   . 
         FIG.  10    is a schematic view of a gas turbine engine including the heat exchanger of  FIG.  1   . 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
       FIG.  1    shows a gas turbine engine heat exchanger  20  providing heat exchange between a first flowpath  900  and a second flowpath  902  ( FIG.  2   ) and thus between their respective first and second fluid flows  910  and  912 . In the exemplary embodiment, the flowpaths  900 ,  902  are gas flowpaths passing respective gas flows  910 ,  912 . In the illustrated example, the first flow  910  enters and exits the heat exchanger  20  as a single piped flow and exits as a single piped flow  910 ; whereas the flow  912  is a flow through a duct. For example, the flow  912  may be sector portion of an axial annular flow surrounding a central longitudinal axis (centerline)  10  of the heat exchanger and associated engine ( FIG.  10   ). There may be multiple such heat exchangers occupying the full annulus of an annular duct or one or more such heat exchangers occupying only a portion of the annulus. 
     Other connections are also possible. For example, a configuration with a single first flow inlet and branched first flow outlets is shown in International Patent Application No. PCT/US2020/067289 (the &#39;289 application), filed Dec. 29, 2020 and entitled “Aircraft Heat Exchanger Assembly”, the disclosure of which is incorporated by reference herein in its entirety as if set forth at length. 
     The heat exchanger  20  ( FIG.  1   ) has an inlet  22  and outlet  24  for the first flow. The exemplary inlet and outlet are, respectively, ports of an inlet manifold  26  ( FIG.  2   ) and an outlet manifold  28  (discussed below bounding an inlet plenum  920  and an outlet plenum  922  respectively) that form respective portions of a combined manifold  29 . Exemplary manifolds are metallic (e.g., nickel-based superalloy). The inlet manifold and outlet manifold may each have a respective fitting  30 ,  32  providing the associated port  22 ,  24 . The manifold  29  has a first face  33  ( FIG.  1   ) along the second flowpath  902  and an opposite second face  34 . The manifold  29  has a leading/upstream end  35  ( FIG.  3   ) and a trailing/downstream end  36 . The manifold  29  has lateral edges/ends  37  and  38 . As is discussed further below, the inlet manifold and outlet manifold are coupled to heat exchanger plates of one or more exemplary plate banks  40 . 
     Each plate bank  40  ( FIG.  1   ) comprises an array of plates  44  (discussed further below) mounted to the manifold first face  33 . In the exemplary embodiment, the first face is generally flat (as opposed to curved) and the plates are parallel to each other. In a first alternative example (not shown), the first face  33  is concave between the lateral ends  37 ,  38  and the plates converge away from the first face (e.g., as may be appropriate with the plates extending axially and radially toward the axis of an annular duct. In a second alternative example, the first face  33  is convex between the lateral ends and the plates diverge away from the first face (e.g., as may be appropriate with the plates extending axially and radially out from the axis of an annular duct). 
     Each plate  44  ( FIG.  4   ) has an inlet port  46  and an outlet port  48 . Exemplary ports  46 ,  48  are mated to ports in the first face  33  of the manifold (a respective outlet port of the inlet manifold and plum and inlet port of the outlet manifold and plenum). Each plate has one or more internal passageways  49  between the ports  46  and  48 . 
     Each plate  44  comprises a body or substrate  52  (e.g., cast or additively manufactured alloy such as nickel-based superalloy) having a leading edge  54 , a trailing edge  56 , a proximal edge  58 , a distal edge  60 , a first face  62  ( FIG.  1   ) and a second face  64 . 
     As is discussed below, one or both faces  62 ,  64  may bear fin arrays  70  ( FIGS.  1 A and  1 B ). The fins are separately formed (e.g., of folded sheetmetal—e.g., nickel-based superalloy) and secured (e.g., brazing, welding, diffusion bonding, and the like) to adjacent substrate(s) (generally see the &#39;740 patent). As is discussed further below, exemplary fins are initially formed as square wave corrugations  72  of even height/amplitude whose troughs  73  or peaks  74  are secured to the associated face  62 ,  64 . The corrugation has legs  75 ,  76  and extends from a first sectional end  77  to a second section end  78 . Along the direction of the individual corrugations (streamwise of the ultimate second flow  912 ) the corrugation has a first end near the plate substrate upstream edge and a second end near the plate substrate downstream edge.  FIG.  1    shows the panels having an overall height H 1  and an exposed height H 2  (which ignores the height of any inlet or outlet fitting portion embedded/received in or adjacent to the manifold). The terminal faces of the terminal plates in the array (the two outer faces at respective ends of the array) may bear fins (not shown) mated to a shroud (not shown) as in the &#39;289 application. 
       FIG.  1 C  shows an alternate plate where adjacent faces of adjacent plates have separate fin arrays. These may be cut from a wave such as via electrodischarge machining (EDM). For example, wire EDM fins are shown in copending U.S. patent application Ser. No. 17/137,946 (the &#39;946 application), filed Dec. 30, 2020, and entitled “Aircraft Heat Exchanger Finned Plate Manufacture”, the disclosure of which is incorporated by reference herein in its entirety as if set forth at length. In particular this facilitates plate arrays where adjacent faces are not parallel (e.g., when mounted radially to the convex OD surface of a manifold). Also see copending U.S. patent application Ser. No. 17/124,790 (the &#39;790 application), filed Dec. 17, 2020, and entitled “Aircraft Heat Exchangers and Plates”, the disclosure of which is incorporated by reference herein in its entirety as if set forth at length. The &#39;790 application also discussed resonance behavior benefits of the face convergence. 
     The proximal edge  58  of each plate is formed along a proximal rail structure (rail or mounting rail)  100  ( FIG.  5   ). The rail structure forms a thickened portion that mounts in a complementary slot (discussed below) to prevent extraction of the plate normal to the rail. The rail structure  100  extends from a first end  102  to a second end  104 . As is discussed further below, the exemplary second end  104  has an apertured mounting ear  110 . The exemplary aperture  112  is an open-end slot between the proximal edge  58  and an outboard surface  114  of the ear. 
     In transverse section, the rail  100  has a pair of tapering shoulder surfaces  120 ,  122  ( FIG.  6 A ). The shoulder surfaces extend to parallel side surfaces  124 ,  126  which, in turn, merge with a base (base surface) formed by the proximal edge  58 . As is discussed further below, the exemplary rail effectively is a dovetail rail received in a dovetail slot  140  ( FIG.  7   ). Each slot  140  has an open distal end or mouth  142  at the face  33 . Each slot  140  has tapering shoulder surfaces  144 ,  146  complementary to the rail shoulder surfaces  120 ,  122 . Each slot has side/lateral surfaces  148 ,  150  complementary to the rail surfaces  124 ,  126 . Each slot has a base surface  152  complementary to the rail base surface or proximal edge  58  and facing and sealed thereto as discussed below. Exemplary slots are machined such as by shaped end mill either fully (machined into a flat surface) or partially (machined from a cast slot precursor such as a right channel). 
     In each slot, there are a pair of ports  160 ,  162  ( FIGS.  8  and  9   ). The port  160  is an outlet port from the inlet manifold/plenum  26 / 920  and the port  162  is an inlet port to the outlet manifold/plenum  28 / 922 . These are respectively in adjacent communication and sealed with the associated plate inlet port  46  and outlet port  48  to pass an associated branch of the first flow  910  and first flowpath  900 . For sealing, about each port  160 ,  162  ( FIGS.  8  and  9   ) the slot base  152  includes a groove  170  ( FIG.  9 A ) accommodating respective seal  172 . Exemplary grooves  170  and seals  172  have a rounded-corner rectangular footprint. Exemplary seals  172  are self-energized metallic rings (e.g., C-seals) or solid elastomeric rings depending upon operating temperature environment. 
     The exemplary slot  140  has a closed first end  154  ( FIG.  7   ) and an open second end  156 . In assembly, the respective individual plates may be installed by sliding their respective rail into the associated slot  140  until the rail is stopped at the slot first end  154 .  FIG.  4    shows a protruding first end section  200  of the rail  100 . In the  FIG.  4 A  sectional view, the portion  200  has an arcuate transition  202  from the trailing edge  56  to an angled or beveled shoulder  206 . The shoulder  206  extends therefrom to an end face  208  essentially normal to the main portion of the proximal edge  58 . Along the first end portion of the proximal edge  58 , there may be a slightly angled ramping transition  210  to aid insertion of the rail  100  into the slot  140 . The closed first end of the slot has surfaces  222 ,  226 , and  228  generally complementary to the surfaces  202 ,  206 , and  208  respectively but without need for any angled surface complementary to the ramping surface  210 . Upon installation, surfaces  206  and  226  will interface in a wedge-like fashion to hold the plate firmly engaged to the manifold slot base  152  near the rail first end  102 . 
     Once the rail has been slid into place, the rail may be secured against extraction via a fastener  240  ( FIG.  1   ). The exemplary fastener also holds the plate firmly engaged to the manifold slot base at the associated second end  104  of the rail. An exemplary fastener  240  is a threaded fastener having a shaft/shank extending through the mounting ear  110  and into the manifold  29 . The exemplary fastener  110  is a bolt (e.g., hex-head) whose shaft  242  is received in a threaded bore  244  ( FIG.  7   ) of the manifold. Thus, after sliding installation of each plate, the associated fastener  240  may be installed and tightened to hold the plate in place. The exemplary installation leaves the bolt head subflush (recessed) to or only slightly proud of the surface  33 . Alternatively, a rounded hex head may help to alleviate turbulent flow. 
       FIG.  10    schematically shows a gas turbine engine  800  as a turbofan engine having a centerline or central longitudinal axis  10  and extending from an upstream end at an inlet  802  to a downstream end at an outlet  804 . The exemplary engine schematically includes a core flowpath  950  passing a core flow  952  and a bypass flowpath  954  passing a bypass flow  956 . The core flow and bypass flow are initially formed by respective portions of a combined inlet airflow  958  divided at a splitter  870 . 
     A core case or other structure  820  divides the core flowpath from the bypass flowpath. The bypass flowpath is, in turn, surrounded by an outer case  822  which, depending upon implementation, may be a fan case. From upstream to downstream, the engine includes a fan section  830  having one or more fan blade stages, a compressor  832  having one or more sections each having one or more blade stages, a combustor  834  (e.g., annular, can-type, or reverse flow), and a turbine  836  again having one or more sections each having one or more blade stages. For example, many so-called two-spool engines have two compressor sections and two turbine sections with each turbine section driving a respective associated compressor section and a lower pressure downstream turbine section also driving the fan (optionally via a gear reduction). Yet other arrangements are possible. 
       FIG.  10    shows the heat exchanger  20  positioned in the bypass flowpath so that a portion of the bypass flowpath  954  becomes the second flowpath  902  and a portion of the bypass flow  956  becomes the second airflow  912 . 
     The exemplary first airflow  910  is drawn as a compressed bleed flow from a diffuser case  850  between the compressor  832  and combustor  834  and returned radially inwardly back through the core flowpath  950  via struts  860 . Thus, the flowpath  900  is a bleed flowpath branching from the core flowpath. 
     The use of “first”, “second”, and the like in the following claims is for differentiation within the claim only and does not necessarily indicate relative or absolute importance or temporal order. Similarly, the identification in a claim of one element as “first” (or the like) does not preclude such “first” element from identifying an element that is referred to as “second” (or the like) in another claim or in the description. 
     One or more embodiments have been described. Nevertheless, it will be understood that various modifications may be made. For example, when applied to an existing baseline configuration, details of such baseline may influence details of particular implementations. Accordingly, other embodiments are within the scope of the following claims.