STACKED HEAT EXCHANGER AND METHOD OF FORMING

Abstract

To provide an additive heat exchanger and a method of forming.SOLUTION: A method of electroforming can be used to prepare a heat exchanger by electroforming the heat exchanger on a mandrel having a smooth and conductive surface. The mandrel is in the shape of at least part of the heat exchanger, and is removed from the electroformed heat exchanger.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. patent application Ser. No. 17 / 192,027, filed March 3, 2021, the entirety of which is incorporated herein by reference.

[0002] The present disclosure relates generally to heat exchangers, and more particularly to a heat exchanger having two or more cooling passages for a turbine engine that utilizes a method for improving surface finish and wall thickness control during electrodeposition. [Background technology]

[0003] Modern engines, such as those used in aircraft, generate a great deal of heat that must be removed from the engine in some manner. Heat exchangers provide one method for removing heat from such engines. For example, heat exchangers may be arranged in a ring about a portion of the turbine engine.

[0004] Oil can be used to dissipate heat from engine components such as engine bearings and generators. Typically, heat is transferred from the oil to the air by an air-cooled oil cooler, more specifically a surface air-cooled oil cooler system, to maintain the oil temperature in a desired range of approximately 100°F to 300°F. In many instances, the environment can be as low as -65°F. Summary of the Invention [Means for solving the problem]

[0005] Aspects and advantages of the present invention will be set forth in part in the description which follows, or may be obvious from the description, or may be learned through the practice of the invention.

[0006] In one aspect, the present disclosure relates to a method of electroforming a heat exchanger, the method comprising the steps of polishing a conductive surface of a mandrel formed as at least a portion of the heat exchanger, electroforming the heat exchanger onto the conductive surface of the mandrel, and removing the mandrel from the electroformed heat exchanger. Includes.

[0007] In yet another aspect, the disclosure relates to a method of electroforming a component, the method including polishing a conductive surface of a mandrel shaped as the component, electroforming the component onto the conductive surface of the mandrel, and removing the mandrel from the component to expose a new surface of the component previously defined by the mandrel, the new surface having a surface roughness (rms) that is less than 32 microinches resulting from polishing the conductive surface prior to electroforming the component.

[0008] In yet another aspect, the present disclosure relates to a method of forming a heat exchanger, the method including the steps of providing a removable mandrel defining a shape of the heat exchanger, coating a surface of the mandrel with a conductive coating to define a cathode, electroforming the heat exchanger onto the cathode with a wall thickness that is between 3 and 4 mils, removing the mandrel from the electroformed heat exchanger, and treating the electroformed heat exchanger to remove residual conductive coating from the electroformed heat exchanger.

[0009] These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of an electrodeposition bath with a mandrel in the form of a partially broken component. [Diagram 2] 1 is a process flow diagram illustrating a method of electroforming a component such as a heat exchanger. [Diagram 3] FIG. 3 is a perspective view of a heat exchanger having a manifold connected by multiple tubes formed by the process shown in FIG. 2 according to various embodiments described herein. [Figure 4] 4 is a schematic cross-sectional view of the tube of FIG. 3 taken along line IV-IV of FIG. 3 according to various embodiments described herein. [Diagram 5] FIG. 4 is a top view of the heat exchanger of FIG. 3. [Figure 6] 6 is a schematic cross-sectional view of a portion of the heat exchanger of FIG. 3, including a portion of the manifold and connecting tubes, taken along line VI-VI of FIG. 3, in accordance with various embodiments described herein. [Figure 7] FIG. 2 is a partial cutaway perspective view of a monolithic heat exchanger having interlaced branched tubes in accordance with various embodiments described herein. [Figure 8] FIG. 2 is a perspective view of a monolithic heat exchanger in the form of a nested spiral set according to various aspects described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present disclosure relates to a heat exchanger having mesh-like passages for cooling fluid. More specifically, the present disclosure relates to a method of electroforming components with improved surface finish and improved wall thickness control that may improve thermal transfer and reduce turbulence of fluid passing along the heat exchanger. For illustrative purposes, aspects of the present disclosure discussed herein are described with a mandrel used during the electroforming process. However, it will be understood that the present disclosure as discussed herein is not limited thereto and may have versatility within the range of configurations utilized for the electroforming process.

[0012] Any directional terms (e.g., radial, up, down, upward, downward, left, right, front, rear, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise) are used for identification purposes only to aid the reader in understanding this disclosure and do not imply any limitations on location, orientation, or use thereof, among others. Terms suggesting connection (e.g., attached, coupled, connected, and joined) should be interpreted broadly and may include intermediate members between element sets and relative movement between elements unless otherwise indicated. Thus, words suggesting connection do not necessarily imply that two elements are directly connected and in a fixed relationship with respect to each other. The illustrated figures are for illustrative purposes only, and the dimensions, positions, order, and relative sizes reflected in the figures attached hereto may be altered. In this specification, a "set" may include any number of elements, including only one. As used herein, "integral monolithic body" or "monolithic body" means a unitary body that is a single, inseparable piece or is formed as a unitary piece at the time of manufacture, rather than being formed by combining separate elements together during manufacture.

[0013] In Figure 1, a system for performing an electroforming process to form metal component 38 (shown in dashed lines) is shown as electrodeposition bath 40. An exemplary bath tank 50 has a conductive fluid electrolyte 52. In one non-limiting example, the fluid electrolyte 52 may include an aluminum alloy carrying alloying metal ions. In an alternative non-limiting example, the fluid electrolyte 52 may include a nickel alloy carrying alloying metal ions.

[0014] An anode 54 is provided within the bath tank 50, spaced apart from a cathode 56. The anode 54 can be a sacrificial anode or an insoluble anode. Although one anode 54 is shown, it is understood that the bath tank 50 can include any number of anodes 54 as desired. The cathode 56 can be a mandrel 58 coated with a conductive material 62, which may include, by way of non-limiting example, copper, silver, or nickel. It is further contemplated that the conductive material 62 may be sprayed, painted, coated, or similarly applied to the mandrel 58 to facilitate formation of the cathode 56. Furthermore, although one cathode 56 is shown in the figures, it is understood that one or more cathodes are contemplated for use within the bath tank 50.

[0015] The mandrel 58 defines a body 60 formed from, by way of non-limiting example, a salvageable material. The body 60 can be made from a salvageable material that can be collected after the electroforming process and reused as another body in another electroforming process. Suitable salvageable materials can include, by way of non-limiting example, wax, plastic, polymer foam, metal, or deformable materials, such as materials that can be collected by melting or leaching. After completion of the electroforming process, the body 60 can be salvaged from the electroformed component, such as through further heating and melting the body 60 at an elevated temperature for salvage of the structural material. In this way, material waste is reduced.

[0016] A controller 64, which may include a power source, may be electrically coupled to the anode 54 and cathode 56 by electrical conduits 66 to form a circuit 67 through the fluid electrolyte 52. Optionally, a switch 68 or sub-controller may be included along the electrical conduits 66 and positioned between the controller 64 and the anode 54 and cathode 56. In operation, an electrical current may be provided from the anode 54 to the cathode 56 through the fluid electrolyte 52 to electroform the monolithic metal component 38 on the mandrel 58. During this current application, metal from the fluid electrolyte 52, such as aluminum, iron, cobalt, or nickel in non-limiting examples, forms a metal layer 70 over the mandrel 58. In one non-limiting example, the monolithic metal component 38 may be a heat exchanger 100.

[0017] The pump (P) and filter (F) may be used to filter and chemically maintain the fluid electrolyte 52 at a certain ion concentration or to remove foreign matter. The filter (F) may comprise a chemical filter material, as a non-limiting example. The heater (H) is provided to regulate the temperature of the electrodeposition bath 40. As a non-limiting example, the heater (H) may be disposed within the bath tank 50 or outside the bath tank 50 near the bath tank 50. Alternatively, the heater (H) may be in fluid communication with the pump (P) to heat the fluid electrolyte 52 as it is pumped by the pump (P).

[0018] 2 illustrates a process 400 for forming a metal component 38. The process 400 is presented for illustrative purposes and may proceed in a different logical order or include additional or intermediate steps unless otherwise stated. Although the process 400 is described in the context of forming a heat exchanger by electrodeposition onto a mandrel, it may be utilized in a similar manner to form other types of bodies using other suitable shapes.

[0019] At 402, the process 400 begins with creating a mandrel 58. The mandrel 58 may be formed, for example, from wax or plastic, or may be formed from other consumable materials. The mandrel defines the shape of the heat exchanger 100. The mandrel 58 may be formed by additive manufacturing, as one non-limiting example, or by injection molding, as another non-limiting example. The mandrel 58 may be removable from the finished electroformed component and may be made from conductive or non-conductive materials. At 404, the mandrel 58 is metallized with a conductive material 62 to form a conductive surface on the mandrel 58. After metallization, the metallized mandrel 58 functions as a cathode in an electrodeposition bath. If the mandrel 58 is formed from a conductive material, the metallization step may not be necessary, while a metal mandrel may be treated with an additional conductive surface to form the cathode.

[0020] Further, at 404, the conductive surface of the mandrel 58 is polished to have a surface roughness (rms) of less than 32 microinches (0.81 micrometers, Ra=29 microinches), where rms is calculated as the root mean square of the surface of the mandrel 58 according to Formula 1 as specified in ASME B46.1. Rms (R in Eq. 1) q ) is the root mean square mean of the profile height deviation from the centerline recorded within the evaluation length (L), where Z(X) is the profile height function. In another example, the surface roughness can be less than 30 microinches.

[0021]

number

[0022] Alternatively, the surface roughness can be calculated as the arithmetic mean of the profile height deviations from the centerline recorded within the evaluation length, Ra(Eq2).

[0023]

number

[0024] It is further anticipated that the rms surface roughness can be less than 100 microinches (2.5 micrometers, Ra=91 microinches). Optionally, in further non-limiting examples, the rms surface roughness can be between 10 and 50 microinches (0.25 and 1.3 micrometers, Ra=9 and 45 microinches), or between 20 and 30 microinches (0.51 and 0.76 micrometers, Ra=18 and 27 microinches). By smoothing and polishing or buffing the conductive material 62 on the surface of the mandrel 58, the rms surface roughness of the heat exchanger 100 can be less than about 30 microinches (0.51 micrometers, Ra=27 microinches). It should be appreciated that a smoother surface, such as that resulting from polishing the mandrel 58, can result in further smoothing of the surface of the finished electroformed component after removal of the mandrel 58. Electrodeposition parameters can be varied to achieve a smooth surface roughness of the mandrel 58 such that the surface roughness is less than 30 microinches prior to smoothing. Exemplary means for smoothing the metal-coated mandrel 58 include, but are not limited to, electropolishing, electrochemical polishing, chemical polishing such as acetone vapor polishing, manual polishing or the use of polishing / grit blasting, or other surface polishing methods known in the art.

[0025] At 406, additional components required to form the heat exchanger may be added to the mandrel 58. In one example, a manifold component may be formed as part of the mandrel, such as by mounting the manifold component to the mandrel. Alternatively, it is contemplated that the manifold may be metal and machined and then later bonded to the mandrel 58 during electrodeposition. It is further contemplated that the manifold component or other added components may be formed as part of the mandrel 58 in step 402 above. It is also contemplated that the mandrel for the manifold may be metal coated in preparation for electrodeposition.

[0026] At 408, the surface of the metal-coated mandrel 58 is activated for electrodeposition. In this step, the surface is treated to remove oxides or other contaminants that may interfere with the electrodeposition process. This step, in addition to polishing the mandrel 58, creates a more favorable or more ideal surface for electrodeposition as opposed to an untreated mandrel.

[0027] At 410, optionally, the metal coated mandrel 58 may be structurally coupled to a support frame for suspending the mandrel 58 within the electrodeposition bath. The cathode mandrel, which will also be metal coated, may be electrically connected to other parts of the system to complete the electrical circuit within the bath required for the electroforming process. In one example, the mandrel 58 is electrically connected to a cable for use within the electrodeposition bath.

[0028] At 412, electrodeposition of components onto the metal-coated mandrel 58 is initiated. A metal layer 70 is deposited onto the cathodic metal-coated mandrel 58 to produce the heat exchanger 100. A set of tubes defining at least a portion of the heat exchanger, such as the plurality of tubes 110 of FIG. 3 discussed below, are integrally and unitarily formed with the manifold during deposition to form a unitary, monolithic heat exchanger component. The deposited metal layer can be a metal alloy and can have a wall thickness of, for example, about 3-4 mils (0.007-0.01 centimeters), where 1 mil is equal to 1 / 1000 of an inch. It is further anticipated that bath parameters, such as bath temperature, can be controlled to provide a desired surface morphology or based on the type or concentration of metal in the bath fluid. The wall thickness achieved by this method of approximately 3-4 mils (0.007-0.01 centimeters) is less than the wall thickness typically achieved by laser-based deposition techniques (typically 12 mils (0.03 centimeters) for comparison). The reduced wall thickness improves localized thermal conductivity while simultaneously reducing component weight. Furthermore, the porosity (or pore size) of the metal layer 70 formed by electrodeposition is approximately 50 microinches (1.3 micrometers). For comparison, the porosity of surfaces formed by laser-based deposition techniques is typically 20-40E-03 inches (5.1E-02-10E-02 centimeters), which is several orders of magnitude higher than the porosity of metal layers formed by the methods described herein.

[0029] At 414, the consumable material comprising the mandrel 58 is removed from the electroformed heat exchanger 100, thereby exposing a new interior or exposed surface 150. In one non-limiting example, an oven bake process may be utilized, while any suitable removal process is contemplated, which may vary based on the particular mandrel material. Further processing of the electroformed heat exchanger component may include flushing with an etchant or other solvent to remove any remaining conductive material 62 from the exposed surface 150 of the electroformed heat exchanger 100. Further processing of the exposed surface 150 may include alternative means of removing conductive material 62, such as sanding / grit blasting. After removal of the mandrel and flushing with the etchant, the final surface roughness rms of the heat exchanger 100 may be 20-30 microinches (0.51-0.76 micrometers, Ra=18-27 microinches). By way of comparison, the rms surface roughness of products formed by laser-based deposition processes typically ranges between 60-100 microinches (1.5-2.5 micrometers, Ra=54-91 microinches).

[0030] Optional final steps 416-420 include visual or other types of inspection of the heat exchanger surfaces, which may include, by way of non-limiting example, fluorescent penetrant inspection for cracks or flaws, precipitation aging heat treatment, and flow and pressure testing.

[0031] Contemplated additional steps may include a post-polishing operation in addition to the first polishing. More specifically, an initial polishing of the mandrel 58 may reduce the roughness of the mandrel 58 to about 30 microinches or less. Further, additional polishing of the final heat exchanger may smooth the surface, for example reducing the roughness by about 50%, such that the final surface roughness after post-polishing may be between 10-15 microinches. Such a low roughness may improve flow efficiency and reduce pressure loss. Additionally, the smooth surface may allow for the use of thinner walls than would otherwise be possible, thereby reducing the overall weight of the components, which may improve the overall efficiency of the system.

[0032] An additive manufacturing process using electrodeposition is disclosed for producing a monolithic, one-piece, high temperature compact heat exchanger with fluid conduits integrated with the manifold housing. A consumable mandrel is used to produce the conductive deposition surface and to construct the fluid connection ports. These fluid conduits are directly integrated with the manifold at the fluid connection ports during the electrodeposition process, thereby eliminating the need for brazing or mechanical crimping to connect these conduits to the manifold. The mandrel is then removed after metal deposition, and flushing with an etchant can be used to remove the conductive deposition surface from the interior surfaces of the heat exchanger.

[0033] Advantageously, the process described herein allows the electroformed components to be directly structurally coupled and integrated to the manifold during the electrodeposition process, thereby eliminating the need for mechanical crimping, brazing, or other metallurgical joining processes. Additionally, the method produces walls that are approximately ⅓ to ¼ thinner than walls produced by conventional laser-based or electroformed deposition processes. The thinner walls of the components provided by the method increase the efficiency and effectiveness of the heat exchanger by promoting heat transfer, and also reduce the overall weight of the components. The method requires less material, reducing manufacturing costs. By smoothing the mandrel in preparation for electrodeposition, the resulting components have surfaces that are significantly smoother (e.g., approximately ⅓ less surface roughness) than if an untreated rough mandrel 58 had been used. The improved smoothness of the component surfaces reduces hydraulic losses during use of the final product, as well as reducing turbulence, aerodynamic drag, or other inefficiencies resulting from non-smooth surfaces. Additionally, the method allows for the production of components with low porosity. The reduced porosity allowed by the method increases the effective thermal conductivity and increases knockdown strength, thereby reducing high cycle fatigue. Overall, the simplicity of the manufacturing process can allow for faster time, lower costs, fewer defects, and overall improvements in the final product, such as the efficiency of heat exchangers, compared to similar components formed by other methods.

[0034] 3, the mandrel 58 as described above and used in the process 400 may take the form of a heat exchanger 100 including a first manifold 102, a second manifold 104, and a tube set 110 extending between the first manifold 102, 104 in a longitudinal or first direction 112. The first manifold 102 and the second manifold 104 are fluidly coupled by the tube set 110 which is joined to the first manifold 102 and the second manifold 104 at a fluid connection fitting 113 to form a conduit or fluid passage F1 for internal refrigerant flow between the first manifold 102 and the second manifold 104. In one embodiment, the first manifold 102, the second manifold 104, and the tube set 110 are formed as a monolithic unit. It should be appreciated that the fluid connection fittings 113 need not be separate or additional elements, but can simply be formed as part of the tube set 110 that mates with a particular manifold 102, 104. It is further contemplated that the fittings 113 need not be included with the heat exchanger 100.

[0035] The tube set 110 is configured such that the tubes 111 are arranged in multiple rows in an axial or second direction 122 and stacked in a third direction 132, where the row stacks are either aligned or staggered from the front to the rear of the heat exchanger 100. The spaces between each tube 111 of the tube set 110 define a flow path F2 from the front to the rear of the heat exchanger 100. The fluid passages F1 and F2 cooperate to allow heat exchange between a first fluid 114 passing through the interior of the tube set 110 and a second fluid 116 passing along the flow path F2 on the exterior surface of the tube set 110.

[0036] Referring now to Figure 4, which is a cross-sectional view taken along section line IV of Figure 3, each tube 111 has an airfoil or teardrop shape. It will be appreciated that the present disclosure includes, but is not limited to, asymmetric, semi-symmetric, and symmetric teardrop and airfoil shapes, such as, for example, laminar flow, arc, Clark "Y", double wedge, early, later, flat bottom, undercamber, teardrop, cambered, and supercritical airfoil shapes, and is not limited to the shapes shown in Figure 3. Additionally, each tube 111 has a leading edge 120 and a trailing edge 121 between which an axial or second direction 122 is defined. A top surface 124 and a bottom surface 126 are further provided in each tube 111 to define a third direction 132 perpendicular to both the first direction 112 and the second direction 122. Thus, an axial cross-sectional area 134 of the tube 111 is defined by the leading edge 120 , the trailing edge 121 , the top surface 124 , and the bottom surface 126 .

[0037] The tube set 110 includes a metal layer 70 having a wall thickness 136 that, in one non-limiting example, is 3-4 mils (0.003-0.004 inches; 0.007-0.01 centimeters). The wall thickness 136 is thick enough to allow the heat exchanger 100 to be self-supporting during operation and reduces the amount of material required during manufacture. Additionally, the wall thickness 136 may reduce the overall weight of the heat exchanger as compared to conventional heat exchangers having conventional wall thicknesses.

[0038] The leading edge 120 of each tube set 110 impinges on the second fluid 116 which enters the heat exchanger 100 and follows a flow path F2 in the axial direction 122 over the elongated teardrop shaped exterior of the tube set 110 with an extended surface area for improved heat transfer. Additionally, pressure drop across the tube sets 110 is minimized by the airfoil shape which reduces the forward profile, minimizes drag across the top and bottom surfaces 124 and 126 of the tube set 110, and benefits from improved flow attachment to these surfaces, improving overall heat transfer. This airfoil profile mitigates the onset of early vortex shedding by moving the flow with improved attachment along the airfoil profile towards the trailing edge 121.

[0039] 5, the trailing edge 121 has a corrugation 128 defined in the first direction 112. The corrugation 128 can be any repeating curved shape, such as a sinusoidal shape. Each tube 111 of the tube set 110 has an axial width 130 in the second axial direction. The axial width 130 varies repeatedly between a maximum value 130a and a minimum value 130b corresponding to the maximum and minimum portions of the corrugation 128. The variation in the axial width 130 of the tubes 111 also results in a variation in the axial cross-sectional area 134 of each tube 111 as defined along the first longitudinal direction 112. In other embodiments, the maximum value 130a and the minimum value 130b of the axial width 130 can be substantially the same, in which case the axial cross-sectional area 134 of each tube 111 of the tube set 110 is substantially uniform or within a range of ±10%. The cross-sectional area can be kept approximately the same while varying the maximum and minimum dimensions of the quasi-elliptical cross-section. This constant cross-sectional area, if kept uniform or approximately uniform, results in lower pressure loss and less turbulence in the channel. However, it is understood that variable cross-sectional areas are also contemplated. Variable cross-sectional areas result in pulsating high and low flow rates, creating turbulence, resulting in a higher heat transfer coefficient h and improved heat transfer. It is therefore understood that a compromise can be made between constant and variable cross-sectional areas, with the constant cross-sectional area being more constant and therefore more favorable for pressure loss, and the variable cross-sectional area being more variable and therefore more favorable for localized heat transfer. In this way, it is further contemplated that each section of the heat exchanger will have different cross-sectional areas, both varying and constant, but located separately.

[0040] 5, a first fluid 114 flows through the first manifold 102, enters the tube set 110 and follows fluid path F1, exits the tube set 110 and enters the second manifold 104. Flow path F2 passes over the exterior surface of the tube set 110 from the front to the rear of the heat exchanger 100. A second fluid 116 enters the heat exchanger 100 at the front, follows flow path F2 by passing over and between the tube sets 110 to exchange heat with the first fluid 114, and exits at the rear of the heat exchanger 100. As shown in FIG. 5, the tube sets 110 may be arranged in a staggered manner.

[0041] 6, the top surface 124 can have a top profile 140 and the bottom surface 126 can have a bottom profile 142, which are shown as regularly repeating curved shapes, such as, for example, sinusoidal shapes. This alignment of the top profile 140 and bottom profile 142 defines a thick portion 144 and a thin portion 146 of the tube 111. It is contemplated that the top profile 140 can be offset from the bottom profile 142, such as, for example, by 1 / 2 a sinusoidal period. Additionally, the thick portion 144 is aligned with the portion of the trailing edge 121 where the axial width 130 is at a maximum value 130a according to the corrugation 128, and the thin portion 146 is aligned with the portion of the trailing edge 121 where the axial width 130 is at a minimum value 130b according to the corrugation 128.

[0042] The top 140 and bottom 142 profiles of the tubes 111 can be varied to improve internal fluid mixing and minimize hydraulic losses. The geometry of the tube sets 110 is designed to include a periodic transverse velocity component to the fluid flow to enhance heat transfer. The cross-sectional area 134 across each tube set 110 is designed to be approximately uniform to minimize velocity changes and associated hydraulic losses. Such uniformity can be achieved through balancing the cross-sectional area changes due to the varying width 130 and the varying thickness of the thicker and thinner sections 144 and 146 such that the greater thicknesses are aligned with the lesser widths 130 and vice versa to achieve a substantially uniform cross-sectional area. The substantially uniform cross-sectional area can reduce velocity changes or pressure losses, thereby maintaining efficiency and improving overall thermal transfer.

[0043] In other embodiments, the fluid passages may be formed as an interlaced trifurcated tube set 210 as shown in FIG. 7. In this case, the junctions have a tetrahedral configuration, such that each flow path has multiple bends. In yet other embodiments, the fluid passages may be formed as a nested spiral set 310 as shown in FIG. 8. The process 400 allows these geometrically complex structures to be formed with advantageous wall thickness, surface smoothness, low porosity, and fewer defects, and without the need for individual sealing connections or assembly of parts by welding or brazing. The manifolds 102, 104 are in-situ bonded to the fluid conduit tubes 110, 210, 310 during electroforming, thereby reducing the possibility of sealing defects or failures.

[0044] Advantages associated with the present disclosure include, but are not limited to, the complex geometry and interlacing configuration of the tubes, which increases heat transfer, reduces fluid or aerodynamic drag, and improves structural stiffness or knockdown strength to resist high cycle fatigue. The tubeset 110 is integrally formed with the manifold, which reduces the likelihood of weak spots in the structure. The electroformed walls of components formed by the methods described herein are significantly thinner than the walls of components formed by other methods. These thinner component walls improve heat transfer, reduce drag or hydraulic losses, and improve the structural integrity of the component. Additionally, improved component surface smoothness improves fluid flow through the final product by reducing frictional forces and reducing aerodynamic drag, flow attachment, or hydraulic losses. Reduced surface defects and reduced porosity of electroformed components improve the strength and heat transfer properties of the components.

[0045] Further aspects of the present disclosure are illustrated by the subject matter of the following sections.

[0046] 1. A method of electroforming a heat exchanger, comprising: polishing a conductive surface of a mandrel formed as at least a portion of the heat exchanger; electroforming the heat exchanger onto the conductive surface of the mandrel; and removing the mandrel from the electroformed heat exchanger.

[0047] The method of any one of the preceding claims, wherein polishing the conductive surface smoothes the conductive surface roughness (rms) to less than 32 microinches (0.81 micrometers, Ra=29 microinches).

[0048] The method of any one of the preceding claims, wherein electroforming the heat exchanger further comprises electroforming the heat exchanger to have a wall thickness that is less than 4 mils (0.01 centimeters).

[0049] The method of any one of the preceding claims, further comprising activating the conductive surface for electroforming.

[0050] The method of any one of the preceding clauses, wherein activating comprises treating the conductive surface to remove contaminants.

[0051] 13. The method of any one of the preceding claims, wherein the electroformed heat exchanger is treated along the interior surface that is exposed when the mandrel is removed.

[0052] 4. The method of any one of the preceding claims, wherein treating the heat exchanger comprises treating the interior surface with an etching solution.

[0053] The method of any one of the preceding claims, further comprising mounting a manifold component onto the mandrel.

[0054] The method of any one of the preceding claims, further comprising metallizing the mandrel to form a conductive surface prior to polishing the conductive surface.

[0055] The method of any one of the preceding claims, further comprising forming a mandrel for shaping at least a portion of a heat exchanger prior to metallizing the mandrel.

[0056] 1. A method of electroforming a component, comprising: polishing a conductive surface of a mandrel shaped as the component; electroforming the component onto the conductive surface of the mandrel; and removing the mandrel from the component to expose a new surface of the component previously defined by the mandrel, the new surface having a surface roughness (rms) that is less than 32 microinches (Ra=29 microinches) resulting from polishing the conductive surface prior to electroforming the component.

[0057] The method of any one of the preceding claims, wherein the component further has a wall thickness that is between 3 and 4 mils.

[0058] The method of any one of the preceding claims, further comprising treating the fresh surface with an etchant.

[0059] The method of any one of the preceding clauses, further comprising activating the conductive surface prior to electroforming by treating the conductive surface to remove contaminants.

[0060] 12. The method of claim 11, wherein the component is made from a material having a porosity that is less than 50 microinches.

[0061] A method of forming a heat exchanger comprising providing a removable mandrel defining a shape of the heat exchanger, coating a surface of the mandrel with a conductive coating to define a cathode, electroforming the heat exchanger onto the cathode to have a wall thickness that is between 3 and 4 mils, and removing the mandrel from the electroformed heat exchanger.

[0062] and treating the electroformed heat exchanger to remove any residual conductive coating from the electroformed heat exchanger.

[0063] The method of any one of the preceding claims, further comprising polishing the conductive coating prior to electroforming.

[0064] The method of any one of the preceding claims, wherein polishing enables the production of a surface roughness (rms) of the heat exchanger that is less than 32 microinches.

[0065] The method of any one of the preceding claims, wherein electroforming further comprises forming a monolithic, unitary heat exchanger comprising a first manifold, a second manifold, and a tube set coupling the first manifold to the second manifold.

[0066] Item 11. The method of any one of the preceding paragraphs, wherein treating the remaining conductive coating includes using an etchant.

[0067] Even if not previously described, the various features and structures of the various aspects can be used in combination with each other as desired. If a feature cannot be shown in all of these aspects, this is not intended to be interpreted as impossible, but is done for the purpose of simplifying the description. Thus, the various features of the various aspects can be mixed and combined to form new examples as desired, whether or not the new examples are explicitly described. Combinations or permutations of features described herein are within the scope of the present disclosure. Numerous other possible embodiments and configurations are contemplated by the present disclosure in addition to the embodiments and drawings shown in the above figures.

[0068] This detailed description of the present disclosure is used as an example to explain the aspects of the disclosure described herein, including the best mode, and also to enable those skilled in the art to practice the aspects of the disclosure, including making and using any device or system and practicing any incorporated methods. The patentable scope of the aspects of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be included within the scope of the claims if they have structural elements that do not differ from the wording of the claims, or if they have equivalent structural elements that do not substantially differ from the wording of the claims.

[0069] Further aspects of the present invention are illustrated by the subject matter of the following sections. 1. A method for electroforming a heat exchanger, comprising the steps of: polishing a conductive surface of a mandrel shaped as at least a portion of a heat exchanger; electroforming a heat exchanger onto the conductive surface of the mandrel; Removing the mandrel from the electroformed heat exchanger. A method comprising: 2. The method of any one of the preceding paragraphs, wherein the conductive surface is smoothed by polishing to a conductive surface roughness (rms) of less than 32 microinches (0.81 micrometers). 3. The method of any one of the preceding paragraphs, wherein electroforming the heat exchanger further comprises electroforming the heat exchanger to have a wall thickness that is less than 4 mils (0.01 centimeters). 4. The method of any one of the preceding claims, further comprising activating the conductive surface for electroforming. 5. The method of any one of the preceding clauses, wherein activating comprises treating the conductive surface to remove contaminants. 6. The method of any one of the preceding claims, wherein the electroformed heat exchanger is treated along the interior surface that is exposed when the mandrel is removed. 7. The method of any one of the preceding claims, wherein treating the heat exchanger comprises treating the interior surface with an etching solution. 8. The method of any one of the preceding claims, further comprising mounting a manifold component onto a mandrel. 9. The method of any one of the preceding claims, further comprising metallizing the mandrel to form a conductive surface prior to polishing the conductive surface. 10. The method of any one of the preceding paragraphs, further comprising forming a mandrel for shaping at least said portion of the heat exchanger prior to metallizing the mandrel. 11. A method of electroforming a component, comprising the steps of: Polishing a conductive surface of a mandrel shaped as a component; electroforming the component onto the conductive surface of the mandrel; removing the mandrel from the heat exchanger to expose new surfaces of the component previously defined by the mandrel; Including, The method wherein the new surface has a surface roughness (rms) that is less than 32 microinches that results from polishing the conductive surface prior to electroforming the component. 12. The method of any one of the preceding paragraphs, wherein the component further has a wall thickness that is between 3 and 4 mils. 13. The method of any one of the preceding claims, further comprising treating the new surface with an etching solution. 14. The method of any one of the preceding clauses, further comprising activating the conductive surface prior to electroforming by treating the conductive surface to remove contaminants. 15. The method of any one of the preceding claims, wherein the component is made from a material having a porosity that is less than 50 microinches. 16. A method of forming a heat exchanger, comprising the steps of: Providing a removable mandrel defining a shape of a heat exchanger; coating a surface of a mandrel with a conductive coating to define a cathode; electroforming a heat exchanger on the cathode with a wall thickness that is between 3 and 4 mils; removing the mandrel from the electroformed heat exchanger; treating the electroformed heat exchanger to remove any residual conductive coating from the electroformed heat exchanger; A method comprising: 17. The method of any one of the preceding claims, further comprising polishing the conductive coating prior to electroforming. 18. The method of any one of the preceding paragraphs, wherein polishing enables the production of a surface roughness (rms) of the heat exchanger that is less than 32 microinches. 19. The method of any one of the preceding clauses, wherein electroforming further comprises forming a monolithic, unitary heat exchanger comprising a first manifold, a second manifold, and a tube set coupling the first manifold to the second manifold. 20. The method of any one of the preceding claims, wherein treating the remaining conductive coating includes using an etchant. [Explanation of symbols]

[0070] 38 Metallic components, monolithic metallic components 40 Electroplating bathtub 50 Bathtub Tank 52 Conductive Fluid Electrolyte 54 Anode 56 Cathode 58 Mandrel 60 Main Unit 62 Conductive Materials 64 Controller 66 Electrical Conduit 67 Electrical Circuits 68 Switch 70 metal layer 100 heat exchanger 102 First Manifold 104 Second Manifold 110 Tube set, fluid conduit tube 111 Tube 112 First Direction 113 Fluid connection fitting 114 First Fluid 116 Second Fluid 120 Leading Edge 121 Trailing edge 122 Second direction, axial direction 124 Top surface 126 Bottom 128 Wave shaped part 130 Maximum 130 Minimum 130 Axial width 130a Maximum 130b Minimum 132 The Third Direction 134 Axial cross-sectional area 136 Wall Thickness 140 Top Profile 142 Bottom Profile 144 Thick part 146 Thin part 150 exposed surfaces 210 Tri-branch tube set, tri-branch tube, fluid conduit tube 310 Nested spiral set F1 fluid passage F2 flow path

Claims

1. 1. A method of electroforming a heat exchanger, comprising the steps of: polishing a conductive surface of a mandrel shaped to conform to at least a portion of the heat exchanger; electroforming the heat exchanger onto the conductive surface of the mandrel; removing the mandrel from the electroformed heat exchanger; Including, The method of claim 1, wherein polishing the conductive surface smoothes the conductive surface to a surface roughness (rms) of less than 32 microinches (0.81 micrometers).

2. The method of claim 1 , wherein electroforming the heat exchanger further comprises electroforming the heat exchanger to have a wall thickness that is less than 4 mils (0.01 centimeters).

3. The method of claim 1 further comprising the step of activating the conductive surface for electroforming.

4. The method of claim 3 , wherein activating comprises treating the conductive surface to remove contaminants.

5. The method of claim 1 , wherein the electroformed heat exchanger is treated along an interior surface that is exposed when the mandrel is removed.

6. The method of claim 5 , wherein the step of treating the heat exchanger comprises treating the interior surface with an etchant.

7. The method of claim 1 , further comprising the step of mounting a manifold component onto the mandrel.

8. The method of claim 1 further comprising the step of metallizing the mandrel to form the conductive surface prior to the step of polishing the conductive surface.

9. The method of claim 8 further comprising forming the mandrel for shaping at least the portion of the heat exchanger prior to the step of metallizing the mandrel.

10. 1. A method of electroforming a heat exchanger component, comprising the steps of: polishing a conductive surface of a mandrel shaped to conform to the component; electroforming the component onto the conductive surface of the mandrel; removing the mandrel from the component to expose a new surface of the component previously defined by the mandrel; Including, the new surface has a surface roughness (rms) that is less than 32 microinches resulting from polishing the conductive surface prior to the step of electroforming the component; The method, wherein polishing the conductive surface smoothes the conductive surface to a surface roughness (rms) of less than 32 microinches (0.81 micrometers).

11. The method of claim 10, wherein the component further has a wall thickness that is between 3 and 4 mils.

12. The method of claim 10 further comprising treating the new surface with an etchant.

13. The method of claim 10 further comprising activating the conductive surface prior to the electroforming step by treating the conductive surface to remove contaminants.

14. The method of claim 10 , wherein the component is made from a material having a porosity that is less than 50 microinches.

15. 1. A method of forming a heat exchanger, comprising the steps of: providing a removable mandrel defining a shape of the heat exchanger; coating a surface of the mandrel with a conductive coating to define a cathode; electroforming the heat exchanger onto the cathode with a wall thickness that is between 3 and 4 mils; removing the mandrel from the electroformed heat exchanger; treating the electroformed heat exchanger to remove any residual conductive coating therefrom; Including, further comprising polishing the conductive coating prior to the electroforming step; The method, wherein the polishing step enables the production of a surface roughness (rms) of the heat exchanger that is less than 32 microinches.

16. 16. The method of claim 15, wherein electroforming further comprises forming a monolithic unitary heat exchanger comprising a first manifold, a second manifold, and a tube set coupling the first manifold to the second manifold.

17. The method of claim 15 , wherein treating the remaining conductive coating comprises using an etchant.

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