Patent Publication Number: US-2023160342-A1

Title: Aircraft Heat Exchangers

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Benefit is claimed of U.S. Patent Application No. 62/963,297, filed Jan. 20, 2020, and entitled “Aircraft Heat Exchangers”, 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. 
     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. 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). Among further uses for heat exchangers in aircraft are power and thermal management systems (PTMS) also known as integrated power packages (IPP). One example is disclosed in United States Patent Application publication 20100170262A1, Kaslusky et al., Jul. 8, 2010, “AIRCRAFT POWER AND THERMAL MANAGEMENT SYSTEM WITH ELECTRIC CO-GENERATION”. Another example is disclosed in United States Patent Application publication 20160362999A1, Ho, Dec. 15, 2016, “EFFICIENT POWER AND THERMAL MANAGEMENT SYSTEM FOR HIGH PERFORMANCE AIRCRAFT”. Another example is disclosed in United States Patent Application publication 20160177828A1, Snyder et al., Jun. 23, 2016, “STAGED HEAT EXCHANGERS FOR MULTI-BYPASS STREAM GAS TURBINE ENGINES”. 
     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 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 turbine engine heat exchanger comprising: a manifold having a first face and a second face opposite the first face; a plurality of first plates along the first face, each first plate having an interior passageway; and a plurality of second plates along the second face, each second plate having an interior passageway. A first flowpath passes through the interior passageways of the first plates, the manifold, and the interior passageways of the second plates. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first flowpath passes sequentially through: the interior passageways of the first plates; the manifold; and the interior passageways of the second plates. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the manifold forms a plenum into which respective first flowpath legs through the first plates merge and from which respective second flowpath legs through the second plates split. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first face is concave and the second face is convex. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first plates and the second plates comprise castings. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first plates and the second plates each have: a proximal edge mounted to the manifold and an opposite distal edge; a forward edge and an aft edge; and an inlet to the respective first passageway and an outlet from the respective first passageway. The first plates&#39; outlets are along the associated first plate proximal edge, forward of the first plates&#39; inlets. The second plates&#39; inlets are along the associated second plate proximal edge. The second plates&#39; outlets are forward of the second plates&#39; inlets. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively: the first plates are circumferentially arrayed in at least one first bank; and the second plates are in at least one second bank, wherein within each second bank the second plates share a common parallel orientation. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, within one to all said banks all plates are joined to each other by wave fins. 
     A further aspect of the disclosure involves, a turbine engine including the turbine engine heat exchanger of any of the foregoing embodiments and further comprising: one or more fan sections; one or more compressor sections aft and downstream of the one or more fan sections along a core flowpath; a combustor section downstream of the one or more compressor sections along the core flowpath; one or more turbine sections downstream of the combustor section along the core flowpath; an outer bypass flowpath; an inner bypass flowpath; and a wall between the outer bypass flowpath and the inner bypass flowpath. Exteriors of the first plates are along the inner bypass flowpath; and exteriors of the second plates are along the outer bypass flowpath. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first flowpath is a compressor bleed flowpath. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first flowpath provides turbine cooling. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the inner bypass flowpath extends from a stage of the one or more fan sections; and the outer bypass flowpath extends from another stage of the one or more fan sections upstream of said stage. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first flowpath extends from within or downstream of the one or more compressor sections. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first plates and the second plates each have: an inner diameter edge and an outer diameter edge; and an inlet to the respective first passageway and an outlet from the respective first passageway. The first plates&#39; outlets are along the associated first plate outer diameter edge, forward of the first plates&#39; inlets. The second plates&#39; inlets are along the associated second plate inner diameter edge. The second plates&#39; outlets are forward of the second plates&#39; inlets. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the first plates&#39; inlets are along the associated first plate outer diameter edge. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the second plates&#39; outlets are along the associated second plate inner diameter edge. 
     Another aspect of the disclosure involves a method for using the turbine engine of any of the foregoing embodiments. The method comprises running the turbine engine to: transfer thermal energy from a flow along the first flowpath to an inner bypass flow along the inner bypass flowpath and an outer bypass flow along the outer bypass flowpath. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, the running: passes the outer bypass flow to the heat exchanger at a first temperature and first pressure; passes the inner bypass flow to the heat exchanger at a second temperature and second pressure greater than the first temperature and first pressure, respectively; and passes the flow along the first flowpath to the heat exchanger at a third temperature and third pressure greater than the second temperature and second pressure, respectively. 
     In a further embodiment of any of the foregoing embodiments, additionally and/or alternatively, flow is generally counterflow to the inner bypass flow and outer bypass flow. 
     Another aspect of the disclosure involves a turbine engine comprising: one or more fan sections; one or more compressor sections downstream of the one or more fan sections along a core flowpath; a combustor section downstream of the one or more compressor sections along the core flowpath; one or more turbine sections downstream of the combustor section along the core flowpath; an outer bypass flowpath; an inner bypass flowpath; and a wall between the outer bypass flowpath and the inner bypass flowpath. The engine further comprises a heat exchanger comprising: a first plate array in the inner bypass flowpath; a second plate array in the outer bypass flowpath; and a manifold between the first plate array and second plate array. 
     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 schematic central longitudinal half sectional view of a turbofan engine. 
         FIG.  2    is an enlarged axial cutaway view of a heat exchanger in the engine of  FIG.  1   . 
         FIG.  3    is a front view of a segment of the heat exchanger. 
     
    
    
     Like reference numbers and designations in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
       FIG.  1    shows a gas turbine engine  20  as an exemplary turbofan engine. The engine  20  has an upstream or inlet end  22  and a downstream or outlet end  24  and a central longitudinal axis or centerline  10 . A core flowpath  920  passing a core flow  922  passes sequentially from the inlet to the outlet through one or more fan sections  30 , one or more compressor sections  32 , a combustor section  34 , and one or more turbine sections  36 . The exemplary engine has at least two bypass flowpaths: an inner bypass flowpath  924  passing an inner bypass flow  926  through an inner duct  40 ; and an outer bypass flowpath  928  passing an outer bypass flow  930  through an outer duct  42 . An outer diameter boundary of the outer duct is formed by a nacelle or case structure (depending upon implementation)  44 . The inner duct  40  and outer duct  42  and their associated flowpaths are separated by a wall or case structure  46 . An inner diameter boundary of the inner duct  40  is formed by a case structure  48 . 
     For purposes of illustration, the exemplary one or more fan sections  30  is a single fan section having two stages  60 ,  62  of blades  61 ,  63  (additional vane stage(s) or other structures not shown and other blade stage counts are possible). The exemplary compressor section  32  is a single compressor section with multiple stages of rotating blades interspersed with non-rotating vanes. The exemplary combustor section  34  is an annular combustor. An alternative combustor is a circumferential array of can-type combustors. The exemplary one or more turbine sections  36  is two turbine sections  36 A,  36 B each comprising one or more rotating blade stages and one or more non-rotating vane stages. The exemplary first turbine section  36 A is upstream of the second section  36 B along the core flowpath  920  to operate at a higher pressure. In the exemplary engine, the first turbine section  36 A directly drives the compressor section  36  via a shaft  70 . The second turbine section  36 B drives the fan section  30  via a shaft  72 . The exemplary fan is driven via a reduction gear system  74  (e.g., epicyclic). 
     In the exemplary engine, the outer bypass flowpath  928  extends from the first fan stage  60 ; whereas, the inner bypass flowpath  924  extends from the second fan stage  62 . Other configurations may have these extend from different stages. There may be more fan stages with either more stages upstream of the outer bypass flowpath or downstream. In other configurations, the inner bypass flowpath may extend from one of the compressor section stages. 
     In the exemplary implementation, a heat exchanger  100  is integrated with the case structure  46 . More particularly, the heat exchanger  100  has a plurality of inner (inner diameter (ID)) plates (panels)  102  extending across the inner bypass flowpath  924  and a plurality of outer (outer diameter (OD)) plates  104  extending across the outer bypass flowpath  928 . In general, the term “plate” or “panel” may be applied at any of several levels of detail. It may identify a body or substrate of an assembly or the greater assembly or subassembly (e.g., a cast substrate plus one or more separately-attached fin arrays). The bypass flows  926  and  930  may be used to cool a further flow  910  ( FIG.  2   ) passing through interiors of the plates  102 ,  104 . For example, the further flow may be a bleed flow bled from within or downstream of the one or more compressor sections  32  (e.g., from a diffuser  80  ( FIG.  1   ) between the compressor and combustor). 
       FIG.  2    further schematically shows details of the heat exchanger  100 . In addition to the plates  102  and  104 , the heat exchanger includes a manifold  106  situated within the wall of the case structure  46 . The exemplary manifold  106  may be a full annulus or a segment thereof or may be a flat segment or some combination. The manifold  106  has an inner diameter (ID) surface  120 , an outer diameter surface  122 , a leading end  124 , and a trailing end  126 . If segmented, the manifold may have a first circumferential end  128  ( FIG.  3   ) and a second circumferential end  130 . The manifold of the heat exchanger may be mounted in an aperture of a main section of the wall of the case structure  46  (e.g., via bolts, brazing, welding, and the like—not shown) to become a portion of the wall separating the two bypass flowpaths and ducts. 
     Each inner plate  102  (or body section/substrate thereof) has a leading end  140  ( FIG.  2   ), a trailing end  142 , an inner diameter (ID) edge  144 , and an outer diameter (OD) edge  146 . Each inner plate  102  has a first face  148  ( FIG.  3   ) and a second face  150  opposite the first face. Similarly, the outer plates (or body section/substrate thereof) each have a leading end  160  ( FIG.  2   ), a trailing end  162 , an inner diameter (ID) edge  164  and an outer diameter (OD) edge  166 , and first and second faces  168  and  170  ( FIG.  3   ), and. In the illustrated embodiment, the inner plate OD edges are mounted to the manifold ID surface  120  and are thus proximal edges (the ID edges being distal edges). Similarly, the outer plate ID edges are mounted to the manifold OD surface  122  and are thus proximal edges (the OD edges being distal edges). 
     Each inner plate  102  has an inlet  152  along the OD edge  146  and an outlet  154  along the OD edge  146 . The inlet and outlet may be on respective plugs  153 ,  155  protruding from a main portion of the OD edge and received in associated sockets in the manifold ID wall. Each outer plate  104  has an inlet  172  along its ID edge  168  and an outlet  174  also along its ID edge. The inlet and outlet may be on respective plugs  173 ,  175  protruding from a main portion of the ID edge and received in associated sockets in the manifold OD wall. Each plate has an interior  158 , 178  ( FIG.  2   ) defining one or more passageways and associated legs/branches of the flowpath  900  between the inlet and outlet. Exemplary plates may be secured to the manifold unit such as by brazing, welding, and/or fasteners. 
     In, the exemplary embodiment of  FIG.  2   , the manifold  106  includes an inlet plenum  970 , an outlet plenum  972 , and a transfer plenum  974 . The heat exchanger  100  has one or more inlets  180  to the inlet plenum  970  and one or more outlets  182  from the outlet plenum  972 . Exemplary inlets and outlets extend from the OD surface  122 . The exemplary inlet(s)  180  and outlet(s)  182  are on respective conduits  184 ,  186  extending radially outward circumferentially centrally from the manifold so as to separate two banks of the outer plates  104  from each other. In distinction, there is a single continuous inner bank. Yet other configurations are possible including circumferential outlets at one or both ends  128 ,  130 , axial inlets or outlets at one or both ends  124 ,  126 , ports on or extending from the manifold ID surface  120 , and the like. For example, a manifold configuration with a single first flow inlet and branched first flow outlets is shown in copending U.S. Patent Application No. 62/957,091 (the &#39;091 application), filed Jan. 3, 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 exemplary inlet plenum  970  distributes/divides the inlet flow from the inlet(s)  180  to all the associated inner plates  102 . The exemplary transfer plenum  974  receives and combines flow from all the associated inner plates  102  and distributes/divides the flow to all the associated outer plates  104 . Alternatively, instead of a transfer plenum  974 , there may be individual passageways coupling individual inner plate outlets  154  to individual outer plate inlets  172 . The outlet plenum  972  collects the outflow from the outer plate outlets  174  and may pass such flow in one combined flow to the outlet  182  or multiple branches for subsequent use. 
     The  FIG.  3    embodiment shows yet a further asymmetry between inner plates  102  and outer plates  104 . The exemplary inner plates&#39;  102  surfaces  148  and  150  converge radially inward to allow the surfaces to be parallel to the adjacent surface of the next plate. This allows a constant/uniform amplitude square wave fin  190  to be secured across both (see the &#39;740 patent). Such fins (e.g., bent sheetmetal such as nickel-based superalloy brazed or diffusion bonded to the associated plate substrate) and exemplary plate body/substrate configurations are disclosed in copending U.S. Patent Application No. 62/963,070 (the &#39;070 application), filed Jan. 19, 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;070 application also discussed resonance behavior benefits of the face convergence. 
     In contrast, the outer panels  104  have generally parallel faces  168  and  170  to achieve a similarly efficient use of square wave fin  192  structure. The exemplary inner plates are thus arranged in a single bank  103  forming an even circumferential array. In distinction, the outer plates are in two banks  105 A and  105 B. The plates in each bank  105 A and  105 B are parallel to each other (thus not exactly radially extending) but the two banks are offset by a small angle. To provide this, the manifold OD face  122  may be progressively stepped (to allow the bank to better conform to and fill the duct segment) or may be locally flat/planar along each outer bank  105 A,  105 B. There also may be a shroud  110 ,  112 A,  112 B over each bank. Exemplary shrouds are sheetmetal (e.g., cut/bent from nickel-based superalloy sheet stock) having respective circumferential walls  111 ,  113  and having end walls. The end walls may abut/join a fin structure of the adjacent terminal plate in the associated plate bank and may be secured to the manifold via welded, brazed, and/or fastener-secured flanges (see the &#39;091 application which also discloses plate body/substrate configurations). The arcuate shroud circumferential wall  111 ,  113  reflects the stepping of the mating manifold surface. Thus, having the two banks slightly diverging from each other facilitates the presence of the inlet conduit  184  ( FIG.  2   ) and/or outlet conduit  186  ( FIG.  3   ) between the banks. 
     The heat exchanger may be used for internal engine cooling purposes (e.g., cooling a compressed bleed flow bled from the compressor and directing it to cool the turbine). Alternative cooling involves similarly drawing bleed air but directing it to elsewhere in the aircraft (e.g., to a PTMS). A single heat exchanger may serve both purposes (with outlet flow split) or there may be multiple such heat exchangers each with a dedicated purpose. Yet another purpose involves non-bleed flows. For example, there may be in-aircraft cooling requirements wherein a flow from the aircraft fuselage is passed to the heat exchanger inlet and returned via the outlet (e.g., a closed-loop system). 
     Exemplary manifold and plate manufacture techniques are as in the &#39;091 application (e.g., casting or additive manufacture of alloys such as nickel-based superalloy). Similarly, exemplary plate interior configurations are as in the &#39;091 application and the &#39;070 application. 
     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.