Multilayer high aspect ratio microchannel device
The multilayer microchannel heat transfer device addresses the cost and efficiency issues of existing methods by stacking layers with shallow channels to form deep, narrow composite microchannels, achieving efficient and cost-effective heat transfer.
Patent Information
- Application Number
- JP2024154435
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-04-17
- Filing Date
- 2024-09-09
- Publication Date
- 2025-04-28
AI Technical Summary
Existing manufacturing processes for creating high aspect ratio microchannels in heat transfer devices, such as vibration heat pipes, are costly and inefficient, with methods like CNC milling being expensive and wet etching unable to produce deep channels.
A multilayer microchannel heat transfer device is fabricated using stacked layers with shallow microchannels and slots, aligning and combining them to form deep, narrow composite microchannels with high aspect ratios, allowing for low-cost and efficient manufacturing.
The solution enables the cost-effective production of microchannel heat transfer devices with high aspect ratio microchannels, improving heat transfer efficiency while maintaining structural integrity and airtightness.
Smart Images
Figure 2025068584000001_ABST
Abstract
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001]
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 590,674, filed October 16, 2023. The disclosure of the above application is incorporated herein by reference in its entirety. (Government Rights)
[0002]
[0002] This invention was made with Government support under FA8650-23-C-5019 awarded by The Air Force Research Laboratory. The Government has certain rights in this invention. [Technical field]
[0003]
[0003] The present teachings relate to microchannel heat transfer devices, such as oscillating heat pipe (OHP) devices, and more particularly to such microchannel devices having microchannels with high aspect ratios (ie, high height-to-width ratios), and methods of manufacturing such devices. [Background technology]
[0004]
[0004] The statements in this section are merely intended to provide background information related to the present disclosure and may not constitute prior art.
[0005]
[0005] Some heat transfer devices, such as oscillating heat pipe (OHP) devices, have strong performance benefits from closely spaced deep, narrow channels, i.e., channels with high aspect ratios (i.e., high height-to-width ratios). OHP devices generally have two conflicting design goals for high heat flux applications: 1) large channel size for increased flow, and 2) minimum channel width and wall width to increase the number of channels in contact with the heat source. Many manufacturing processes for making deep, narrow channels, such as CNC milling, are costly, and conversely, methods for making channels more cheaply (e.g., slitting saws) have significant limitations. Thus, manufacturing designs that allow low-cost manufacturing of complex, high-aspect ratio channels are desirable. Wet etching is a low-cost manufacturing process, but it cannot make deep channels with high aspect ratios. Summary of the Invention
[0006]
[0006] In various embodiments, the present disclosure relates to microchannel heat transfer devices such as oscillating heat pipe (OHP) devices, heat exchangers, cold plates, loop heat pipes, heat pipes, thermosiphons, bipolar plates, microfluidic technologies, and more, and specifically provides innovations relating to devices and methods for manufacturing such devices having multiple layers of material with shallow microchannels and / or slots within each layer stacked to create deep, narrow fluid microchannels with high aspect ratios.
[0007]
[0007] For example, in various embodiments, the present disclosure provides a microchannel heat transfer device comprising a first outer or upper layer having at least one shallow, micro-sized, elongated first recess formed in the first outer or upper layer having a desired pattern or array and desired geometric shape, a second outer or lower layer having at least one shallow, micro-sized, elongated second recess formed in the second outer or lower layer having the same desired pattern or array and geometric shape as the at least one first elongated recess, and at least one intermediate or interstitial layer having at least one micro-sized, elongated gap slot formed therethrough having the same desired pattern or array and desired geometric shape as the first and second elongated recesses. The first outer layer, the second outer layer, and the at least one interstitial layer are stacked and bonded together with one or more interstitial layers disposed between the first and second outer layers, whereby at least one first elongated recess in the first outer layer, at least one second elongated recess in the second outer layer, and at least one elongated interstitial slot in the at least one interstitial layer(s) are aligned and combined to form at least one deep, narrow, composite microchannel having a high aspect ratio enclosed in the resulting multi-layer microchannel device.
[0008]
[0008] This summary is provided solely for the purpose of summarizing various illustrative embodiments of the present disclosure so as to provide a basic understanding of various aspects of the teachings herein. Various embodiments, aspects, and advantages will become apparent from the following detailed description, when read in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments. It should therefore be understood that the description and specific examples set forth herein are intended for illustrative purposes only and are not intended to limit the scope of the present teachings.
[0009]
[0009] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present teachings in any way. [Brief description of the drawings]
[0010] [Figure 1A]
[0010] An illustrative example of a multilayer microchannel heat transfer device comprising a first outer layer, a second outer layer, and at least one interstitial layer disposed therebetween, according to various embodiments of the present disclosure. [Figure 1B]
[0011] 1B is an illustrative exploded view of the multi-layer microchannel heat transfer device shown in FIG. 1A according to various embodiments of the present disclosure. [Figure 2A]
[0012] 2 is an illustrative cross-sectional view of the multi-layer microchannel heat transfer device shown in FIG. 1 taken along line BB according to various embodiments of the present disclosure. [Figure 2B]
[0013] 2B is an illustrative exploded view of the cross-sectional view shown in FIG. 2A according to various embodiments of the present disclosure. [Figure 3A]
[0014] FIG. 2C is an illustrative illustration of a multi-layer microchannel heat transfer device as shown in FIG. 2B, in accordance with various embodiments of the present disclosure, wherein the device comprises a layer of brazing material disposed between a first outer layer, a second outer layer, and an interstitial layer(s). [Figure 3B]
[0015] 1A-1C are illustrative top views of a layer of braze material having an elongated slot formed therein with a support tab spanning the elongated slot in accordance with various embodiments of the present disclosure; [Figure 4A]
[0016] 1A-1C are illustrative top views of an interstitial layer having elongated slots formed therein with support tabs spanning the elongated slots, according to various embodiments of the present disclosure; [Figure 4B]
[0017] 4B is an illustrative illustration of a portion of the interstitial layer shown in FIG. 4A illustrating elongated slots and support tabs according to various embodiments of the present disclosure. [Figure 4C]
[0018] 4B is an illustrative illustration of a portion of the interstitial layer shown in FIG. 4A illustrating elongated slots and support tabs according to various other embodiments of the present disclosure. [Diagram 5]
[0019] FIG. 3B is an illustrative exploded view of the multi-layer microchannel heat transfer device shown in FIG. 3A according to various embodiments of the present disclosure, where the brazing layer is separate and independent from the first outer layer, the second outer layer, and the interstitial layer(s). [Figure 6A]
[0020] FIG. 2 is an illustrative cross-sectional view of a slice of the multilayer microchannel heat transfer device shown in FIG. 1 between lines AA and BB, in accordance with various embodiments of the present disclosure, where the device includes a braze layer and the elongated slots in the interstitial layer are formed as deep and wide slots. [Figure 6B]
[0021] FIG. 2 is an illustrative cross-sectional view of a slice of the multilayer microchannel heat transfer device shown in FIG. 1 between lines AA and BB, in accordance with various other embodiments of the present disclosure, where the device includes a braze layer and the elongated slots of the interstitial layer are formed as interconnecting shallow wide slots. [Figure 6C]
[0022] FIG. 2 is an illustrative cross-sectional view of a slice of the multilayer microchannel heat transfer device shown in FIG. 1 between lines AA and BB, in accordance with various other embodiments of the present disclosure, wherein the device comprises a brazing layer disposed on one or more faces on one or more of the first outer layer, the second outer layer, and the interstitial layer(s) as a cladding. [Figure 7]
[0023] 2 is an illustrative cross-sectional view of the multi-layer microchannel heat transfer device shown in FIG. 1 taken along line BB, where the device comprises multiple interstitial layers, according to various other embodiments of the present disclosure. [Figure 8]
[0024] FIG. 2 is an illustrative cross-sectional view of the multilayer microchannel heat transfer device shown in FIG. 1 along line BB, in accordance with various other embodiments of the present disclosure, wherein the device comprises a plurality of interstitial layers disposed between a first outer cover layer and a second outer cover layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011]
[0025] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
[0012]
[0026] The following description is merely exemplary in nature and is in no way intended to limit the present teachings, application, or uses. The drawings are not intended to be limiting. Like reference numerals are used to refer to like elements throughout the specification. Additionally, the embodiments disclosed below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that those skilled in the art can utilize their teachings. Similarly, it should be understood that the drawings are intended to illustrate and clearly disclose embodiments currently contemplated by those skilled in the art, but are not intended to be manufacturing level drawings or representations of the final product, and may include simplified conceptual diagrams for ease of understanding or explanation. Similarly, the relative size and arrangement of components may differ from that shown and still operate within the spirit of the invention.
[0013]
[0027] As used herein, the word "exemplary" or "illustrative" means "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" or "exemplary" should not necessarily be construed as preferred or advantageous over other implementations. All implementations described below are illustrative implementations provided to enable those skilled in the art to practice the disclosure and are not intended to limit the scope of the appended claims.
[0014]
[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing certain illustrative embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an", and "the" may be intended to include the plural forms unless the context clearly indicates otherwise. The terms "comprises", "comprising", "including", and "having" are inclusive and thus specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring their execution in the particular order discussed or illustrated, unless specifically identified as an order of execution. It is also understood that additional or alternative steps may be employed.
[0015]
[0029] When an element, object, device, apparatus, component, region, section, etc. is referred to as being "on," "engaged to or with," "connected to or with," or "coupled to or with" another element, object, device, apparatus, component, region, section, etc., it may be directly on, engaged to, connected to, or coupled to the other element, object, device, apparatus, component, region, section, etc., or there may be intervening elements, objects, devices, apparatus, components, regions, sections, etc. In contrast, when an element, object, device, apparatus, component, region, section, etc. is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another element, object, device, apparatus, component, region, section, etc., there may be no intervening element, object, device, apparatus, component, region, section, etc. Other words used to describe relationships between elements, objects, devices, apparatus, components, regions, sections, etc. should be interpreted similarly (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.).
[0016]
[0030] As used herein, the phrase "operably connected to" is understood to mean that two or more elements, objects, devices, apparatus, components, etc. are operatively and / or cooperatively connected to one another directly or indirectly, such that an operation or function of at least one of the elements, objects, devices, apparatus, components, etc. imparts or causes an operation or function of at least one other of the elements, objects, devices, apparatus, components, etc. Providing or causing such an operation or function may be unilateral or bilateral.
[0017]
[0031] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. For example, A and / or B includes only A, or only B, or both A and B.
[0018]
[0032] Terms such as first, second, third, etc. may be used herein to describe various elements, objects, devices, apparatus, components, regions, or sections, etc., but these elements, objects, devices, apparatus, components, regions, or sections, etc. should not be limited by these terms. These terms may be used only to distinguish one element, object, device, apparatus, component, region, or section, etc. from another element, object, device, apparatus, component, region, or section, etc., and do not necessarily imply a sequence or order unless clearly indicated by context.
[0019]
[0033] Moreover, it should be understood that the various directions, such as "upper", "lower", "bottom", "top", "left", "right", "first", "second", etc., are made solely with respect to description in conjunction with the drawings, and that components may be oriented differently, for example, during shipping and manufacturing, as well as during operation. It should be understood that the details herein should be construed as illustrative and non-limiting, as many different embodiments may be made within the concept(s) taught herein, and as many modifications may be made in the embodiments described herein.
[0020]
[0034] In various embodiments, the present disclosure provides innovations related to microchannel heat transfer devices, such as heat exchangers, cold plates, loop heat pipes, heat pipes, thermosiphons, bipolar plates, microfluidic technologies, etc., having multiple material layers (e.g., two outer layers and at least one intermediate or interstitial layer) with shallow channels and / or slots formed within the multiple material layers that are stacked and bonded together to create a multi-layer device with an internal deep and narrow multi-layered compound fluidic microchannel, e.g., a microchannel with a high aspect ratio. In various other embodiments, the present disclosure provides innovations related to the manufacture of such devices. Although the present disclosure is applicable to all microchannel heat transfer devices, such as heat exchangers, cold plates, loop heat pipes, heat pipes, thermosiphons, bipolar plates, microfluidic technologies, etc., for clarity and brevity, the present disclosure illustratively describes and illustrates the device and the method of manufacturing such a device with respect to an oscillating heat pipe (OHP) device, but the scope of the present disclosure should not be construed as being limited to such OHP devices and the method of manufacturing.
[0021]
[0035] In general, OHP devices are passive heat transfer devices that transport heat using a saturated two-phase working fluid hermetically sealed in capillary-sized OHP channels (e.g., microchannels) formed in and enclosed within the body of the device. The hydraulic diameter of the OHP microchannel is small enough and the surface tension of the working fluid is large enough so that the OHP microchannel has a capillary effect on the working fluid, dispersing the working fluid in discrete liquid plugs and vapor bubbles throughout the interior area of the OHP microchannel. In general, the OHP microchannel has a tortuous path that travels between areas of the body in thermal contact with one or more heat sources (e.g., electronic devices such as integrated circuit semiconductor elements or other heat-generating devices provided, disposed on, integrally formed with, or fabricated on the body) and areas of the body in thermal contact with one or more heat sinks or cooling zones. When heat from the heat source(s) is absorbed by the working fluid, the resulting evaporation and condensation processes of the working fluid create a pressure imbalance within the OHP microchannel, which, combined with the random distribution of liquid plugs and vapor bubbles, generates the motion of a two-phase mixture within the OHP microchannel, as described below.
[0022]
[0036] More specifically, the OHP microchannels are integrally formed within and enclosed within the body, passing near and / or adjacent and / or in close proximity (e.g., within about one to several thousand microns) to heat absorbing regions of the body (e.g., areas of the body having heat source(s) disposed on or integrally formed therewith) and passing near and / or adjacent and / or in close proximity (e.g., within about one to several thousand microns) to heat exhaust regions of the body (e.g., areas of the body that are free of heat source(s) and / or in thermally conductive contact with a heat sink or cooling device / system). When heat is absorbed from the heat absorbing regions (also known as evaporator regions) by the working fluid within the OHP microchannels, evaporation of the working fluid occurs and the capillary dimensions of the OHP microchannels (e.g., hundreds of nanometers to tens of thousands of microns, in some cases up to about 1.0 inch) force the working fluid into liquid plugs and rows of vapor bubbles. The liquid plugs and rows of vapor bubbles create a pressure imbalance in the OHP microchannels. This pressure imbalance causes the working fluid to move in the OHP microchannels, thereby transferring heat (e.g., both latent and sensible heat) from the heat absorption region (also known as the evaporator region) to the heat exhaust region(s) of the body (also known as the condenser region(s)), where the heat of the gas phase working fluid is exhausted into the ambient air and / or into a heat sink or cooling device / system. Once the heat of the gas phase working fluid is exhausted, the gas phase working fluid returns to a liquid phase and then returns to the heat absorption region(s) of the body, repeating the evaporation-condensation cycle to continuously remove heat from and cool the heat source and the entire OHP device.
[0023]
[0037] 1A, 1B, 2A, and 2B, generally, the disclosed devices and methods of fabricating the devices provide a multi-layer microchannel heat transfer device 10 that includes one or more shallow, narrow, multi-layer, compound microchannels 18 having a high width-to-depth aspect ratio. The device 10 can be manufactured with high throughput and low cost, and the multi-layer, compound microchannel(s) 18 are generally closely packed and have structural integrity, as well as local and overall tightness between adjacent channels and from the surrounding environment.
[0024]
[0038] For example, in various embodiments, the present disclosure provides a multi-layer microchannel heat transfer device 10. The device 10 comprises a multi-layer microchannel heat transfer body 12 having at least one multi-layer composite microchannel 18 (e.g., at least one composite OHP microchannel) formed within and enclosed within the body 12. The multi-layer microchannel heat transfer body 12 is structured and operable to remove heat from one or more heat sources 14 (e.g., electronic devices such as semiconductor devices or other heat generating devices) provided on, disposed on, integrally formed with, or fabricated with the body 12 via the multi-layer composite microchannel(s) 18 and transfer or spread the removed heat across a surface area of the body 12, where the removed heat is exhausted to the surrounding environment or other suitable heat sink device or system in thermal contact with the body 12. In various embodiments, the multi-layer composite microchannel(s) 18 are formed to be serpentine microchannel(s) having a generally serpentine shape that traverses a portion or all of the body 12 internally.
[0025]
[0039] The multi-layer microchannel heat transfer body 12 comprises an upper or first outer layer, plate, panel, stratum, or substrate 12A, a lower or second outer layer, plate, panel, stratum, or substrate 12B, and one or more intermediate or interstitial layers, plates, panels, stratum, or substrates 12C disposed between and bonded to the first and second outer layers 12A, 12B. The first outer layer 12A includes one or more micro-sized shallow first elongated recesses or channels 18A formed or disposed (e.g., milled or etched, e.g., wet etched) in its first surface 12A'. The first elongated recess(es) 18A are formed or disposed in the first surface 12A' to have a desired pattern, path, array, or shape (e.g., a substantially serpentine pattern). The second outer layer 12B includes one or more shallow second micro-sized elongated recesses or channels 18B formed or disposed (e.g., milled or etched, e.g., wet etched) in its first surface 12B'. The second elongated recess(es) 18B are formed or disposed in the first surface 12B' to have the same pattern, path, array, or shape (e.g., a substantially serpentine pattern) as the first elongated recess(es) 18A. The interstitial layer(s) 12C include one or more micro-sized elongated slots 18C formed or cut (e.g., milled or etched, e.g., wet etched) in each respective interstitial layer 12C and extending through each respective interstitial layer 12C. The elongated slot(s) 18C are formed or cut through each respective interstitial layer 12C to have the same pattern, path, array, or shape (e.g., a substantially serpentine pattern) as the first and second elongated recess(es) 18A and 18B.Micro-sized, as used herein, is understood to mean that the first elongated recess(es) 18A, the second elongated recess(es) 18B, and the elongated slot(s) 18C have dimensions measured in 0.001 inch increments, for example, in various instances, the first and second elongated recess(es) 18A and 18B can have a width of 0.005-0.200 inches and a depth of 0.005-0.400 inches, and the elongated slot(s) 18C has a width of 0.005-0.200 inches and a depth of 0.005-0.400 inches.
[0026]
[0040] As described above, the first outer layer 12A, the second outer layer 12B, and one or more interstitial layers 12C are stacked and bonded together with the interstitial layer(s) 12C disposed between the first outer layer 12A and the second outer layer 12B to form the body 12 of the multilayer microchannel heat transfer device 10. More specifically, the first outer layer 12A, the second outer layer 12B, and the interstitial layer(s) are stacked and bonded together with one or more interstitial layers disposed between the first and second outer layers, such that the first elongated recess(es) 18A in the first outer layer 12A, the second elongated recess(es) 18B in the second outer layer 12B, and the elongated slot(s) 18C in the interstitial layer(s) 12C are aligned, stacked, and combined to form at least one composite deep and narrow multilayer composite microchannel 18 disposed within and enclosed within the resulting body 12 of the multilayer microchannel heat transfer device 10.
[0027]
[0041] 1A, 1B, 2A, 2C, 3A, and 3B, the first outer layer 12A, the second outer layer 12B, and the interstitial layer(s) 12C may be stacked and bonded together using any suitable means and methods (e.g., brazing, diffusion bonding, ultrasonic welding, etc.) suitable for providing an airtight seal between the first layer 12A, the second layer 12B, and the interstitial layer 12C at the interior channel walls 22 between adjacent portions or sections of the multilayer composite microchannel(s) 18 (referred to herein as an interior airtight sealing), and between a portion or section of the multilayer composite microchannel(s) 18 and the exterior sidewall 26 of the body 12 (i.e., between a portion or section of the multilayer composite microchannel(s) 18 and the exterior ambient environment surrounding the device 10) (referred to herein as an exterior airtight sealing). As illustrated in the various figures, the internal channel wall 22 is a composite of the internal channel wall section 22A formed in and provided by the first outer layer 12A, the internal channel wall section 22B formed in and provided by the second outer layer 12B, and the internal channel wall section 22C formed in and provided by the interstitial layer(s) 12C. Additionally, in embodiments in which the first, second, and interstitial layer(s) 12A, 12B, and 12C are joined together using a braze layer 30 (described below), the internal channel wall 22 is a composite of the internal channel wall section 22A formed in and provided by the first outer layer 12A, the internal channel wall section 22B formed in and provided by the second outer layer 12B, the internal channel wall section 22C formed in and provided by the interstitial layer 12C, and the internal channel wall section 22D formed in and provided by the braze layer 30 (described below).
[0028]
[0042] For example, as illustratively illustrated in Figures 3A and 3B, in various embodiments, one or more layers 30 of brazing material (e.g., a material having a lower melting temperature than the material from which the first, second, and interstitial layers 12A, 12B, 12C are fabricated) can be disposed between the first outer layer 12A and the adjacent interstitial layer 12C, between the second outer layer 12B and the adjacent interstitial layer 12C, and between adjacent interstitial layers 12 when the body 12 includes more than one interstitial layer 12C. In such an embodiment, a layer of brazing material 30 (e.g., a sheet of brazing material) can be disposed between adjacent first, second, and gap layers 12A, 12B, 12C, after which a compressive force is applied to the aligned and stacked adjacent first, second, and gap layers 12A, 12B, 12C, and the aligned and stacked adjacent first, second, and gap layers 12A, 12B, 12C are heated such that the brazing layer 30 melts and hermetically seals the first, second, and gap layers 12A, 12B, 12C together (i.e., hermetically seals the first, second, and gap layers 12A, 12B, 12C together internally and externally). In various embodiments, one or more of the braze layers 30 are fabricated or prepared (e.g., etched, milled, cut, or etched, e.g., wet etched) to have one or more elongated slots 18D extending through each respective braze layer 30, the elongated slot(s) 18D having the same pattern, path, array, or shape (e.g., a substantially serpentine pattern) as the first and second elongated recess(es) 18A and 18B in the first and second layers 12A and 12B and the elongated slots 18C in the interstitial layer(s) 12C. The elongated slot(s) 18D of the braze layer form and define the inner channel wall section 22D of the braze layer.
[0029]
[0043] As described above, the first and second elongated recess(es) 18A and 18B are formed or disposed in the first faces 12A' and 12B' of the first and second outer layers 12A and 12B using any suitable means for forming, creating, or disposing the elongated recess(es) 18A in the first outer layer 12A, such as milling or etching. For example, in various embodiments, a wet etching process is used to form the wide and shallow elongated recess(es) 18A and 18B in the first faces 12A' and 12B' of the first and second outer layers 12A and 12B. Similarly, as described above, the elongated slot(s) 18C are formed, created, or disposed through the interstitial layer(s) 12C using any suitable means, such as milling or etching. For example, in various embodiments, a wet etching process is used to form the slot(s) 18C to have substantially the same width as the shallow elongated recess(es) 18A and 18B in the first and second outer layers 12A and 12B. As illustratively illustrated in FIGS. 2A, 2B, and 2C, in various embodiments, one or more wide, shallow, elongated recesses having substantially the same width as the shallow elongated recess(es) 18A and 18B can be etched in the opposing faces 12C′ and 12C″ of the respective interstitial layers 12C such that the opposing elongated recesses intersect, interconnect, and fluidly connect to form the elongated slot(s) 18C. Alternatively, the elongated slot(s) can be etched or milled through the entire thickness of the respective interstitial layers 12C to have substantially the same width as the shallow elongated recess(es) 18A and 18B.
[0030]
[0044] 1A, 1B, 2A, 2C, 3A, 3B, 4A, 4B, and 4C, as described above, the elongated slots 18C formed in the interstitial layer(s) 12C extend through the entire thickness of the respective interstitial layer 12C. As one skilled in the art will readily appreciate, when the elongated slots 18C are formed, created, or disposed through the respective interstitial layer 12C, the material remaining and forming, providing, or defining the internal channel wall section 22C of the respective interstitial layer 12C will have little or no material connecting the internal channel wall section 22C to the remaining structure (e.g., surrounding structure) of the respective interstitial layer 12C. As such, the internal channel wall section 22C will either fall off or become detached from the remaining structure, or become unstable and difficult or impossible to precisely align with the internal channel wall sections 22A and 22B of the first and second outer layers 12A and 12B when the respective layers are stacked and bonded together. Thus, in various embodiments, the elongated slots 18C are formed, created, or disposed through the interstitial layer(s) 12C to have a plurality of support tabs 34 extending across each elongated slot 18C and connecting each interior channel wall section 22C to an adjacent interior channel wall section 22C and / or to a perimeter section 38 defined and disposed between the portion of the elongated slot 18C closest to the body sidewall 26 and the body sidewall 26. Note that the location and number of support tabs 34 in FIG. 4A are illustrative only, and the location and number of support tabs 34 in each elongated slot 18C may vary in number and location and remain within the scope of the present disclosure. Additionally, the number and location of support tabs 34 within each elongated slot 18C may vary between adjacent interstitial layers 12C and remain within the scope of the present disclosure.
[0031]
[0045] The support tabs 34 provide interconnections between the multiple internal channel wall sections 22C and between the internal channel wall sections 22C and the peripheral wall section 38. Moreover, the support tabs 34 provide alignment stability for the internal channel wall sections 22C so that the internal channel wall sections 22C and the elongated slots 18C of the interstitial layer(s) 12C can be precisely aligned and mated or matched with the internal channel wall sections 22A and 22B and the first and second elongated recesses 18A and 18B of the first and second outer layers 12A and 12B, respectively, when the respective layers are stacked and bonded together. As illustratively illustrated in FIG. 4B, in various embodiments, the support tabs 34 are formed within the elongated slots 18C such that the height H of one or more of the support tabs 34 is less than the thickness T of the respective interstitial layer 12C. Alternatively, as illustratively illustrated in FIG. 4C, in various embodiments, the support tabs 34 are formed within the elongated slots 18C such that the height H of one or more support tabs 34 is substantially equal to the thickness T of the respective gap layer 12C.
[0032]
[0046] As explained above, in various embodiments, a braze layer 30 having an elongated slot(s) 18D formed therein can be disposed between a first outer layer 12A and an adjacent interstitial layer 12C, between a second outer layer 12B and an adjacent interstitial layer 12C, and between adjacent interstitial layers 12C (in the case of more than one interstitial layer 12C), after which the braze layer 30 and the first outer layer, second outer layer, and interstitial layers 12A, 12B, 12C are stacked and aligned such that the internal channel wall sections 22A, 22B, and 22C, and hence the first and second elongated recesses 18A and 18B, and the elongated slots 18C are aligned to form, define, and provide a composite microchannel(s) 18. A compressive force is then applied to the aligned and stacked first, second, and gap layers 12A, 12B, 12C, and the aligned and stacked first, second, and gap layers 12A, 12B, 12C are heated to a temperature at which the braze layer 30 melts and hermetically seals the first, second, and gap layers 12A, 12B, 12C together (i.e., hermetically seals the first, second, and gap layers 12A, 12B, 12C together internally and externally).
[0033]
[0047] In embodiments where the braze layer 30 is separate and distinct from the interstitial layer(s) 30, the elongated slot(s) 18C of the interstitial layer(s) 30 will include the support tab(s) 34 as described above. Additionally, the elongated slot(s) of the braze layer 30 will also be formed, fabricated, or disposed through the braze layer 30 to have a plurality of support tabs 42, as illustratively illustrated in Figures 3B and 5. The braze layer support tabs 42 extend across each elongated slot 18D to connect each interior channel wall section 22D to an adjacent interior channel wall section 22D and / or to a perimeter section 44 defined and disposed between the portion of the elongated slot 18D closest to the body sidewall 26 and the body sidewall 26. Similar to the interstitial layer(s) 12C, the support tabs 42 of the braze layer 30 provide alignment stability for the internal channel wall section 22D of the braze layer so that the internal channel wall section 22D and the elongated slot 18D of the braze layer 30 can be precisely aligned and mated or matched with the internal channel wall sections 22A, 22B, and 22C of the first and second outer layers 12A and 12B, respectively, and the first and second elongated recesses 18A and 18B, and the elongated slot 18C of the interstitial layer 30 when the respective layers are stacked and bonded together. It should be noted that the location and number of the support tabs 42 in FIG. 3B are illustrative only, and the location and number of the support tabs 34 in each elongated slot 18D can vary in number and location and remain within the scope of the present disclosure. Additionally, the number and location of the support tabs 42 in each elongated slot 18D can vary between adjacent braze layers 30 and remain within the scope of the present disclosure.
[0034]
[0048] 1A, 1B, 3A, 6A, 6B, and 6C, in various embodiments, each interstitial layer 30 can be fabricated to include (i.e., be clad with) a braze layer 30 disposed on one or both of faces 12C′ and 12C″, where the braze layer(s) 30 are fabricated from a material (e.g., aluminum 4004, aluminum 4043, silver, nickel, etc.) having a lower melting temperature than the material (e.g., alloy aluminum) from which the core interstitial layer 12C is fabricated. As used herein, the terms / phrases “cladding” or “clad with” (e.g., faces 12C′ and 12C″ are clad with braze layer 30) should be understood to mean two or more layers of different materials or alloys fused together in the form of a plate, sheet, or foil.
[0035]
[0049] As explained above, the elongated slot(s) 18C of each interstitial layer 12C can be formed or cut using any suitable device, means, or method, such as milling or wet etching. As will be readily understood by one of ordinary skill in the art, in embodiments in which both sides 12C′ and 12C″ of one or more interstitial layers 12C are clad with a braze layer 30 disposed thereon, one or both of the braze layers 30 may need to be cut, milled, or etched to provide the braze layer elongated slot 18D, after which the interstitial layer elongated slot(s) 18C may be cut, milled, or etched to provide the interstitial layer elongated slot 18C. However, to prevent the internal channel wall section 22C of the gap layer(s) 12C from falling off or becoming detached from the rest of the structure, either a support tab 34 of the gap layer needs to be formed or provided in the elongated slot 18C of the gap layer as described above, or a support tab 42 of the brazing layer needs to be formed or provided in the elongated slot 18D of the brazing layer 30 (if the gap layer 12C is clad with only one brazing layer 30) or one of the two brazing layers 30 (if the gap layer 12C is clad with only one brazing layer 30), as described above.
[0036]
[0050] For example, in various embodiments in which both sides 12C' and 12C'' of the interstitial layer 12C are clad with a braze layer 30, as illustratively illustrated in FIG. 6A, the elongated slots 18C of the interstitial layer can be formed or cut (e.g., milled or etched) by first removing (e.g., milling or etching) the braze material of one of the braze layers 30 to form the elongated slots 18D of the braze layer. Then, wide and deep elongated slot(s) having substantially the same pattern, path, array, or shape and width as the shallow elongated recess(es) 18A and 18B, but with a depth equal to the thickness T of the interstitial layer 12C, can be formed or cut (e.g., milled or etched) in the respective side 12C' or 12C'' of the interstitial layer 12C. Material from the opposing braze layer 30 can then be removed (e.g., milled or etched) to form elongated slots 18D of the braze layer having substantially the same pattern, path, array, or shape and width as the shallow elongated recess(es) 18A and 18B, including braze layer support tabs 42, as described above. In such an embodiment, the braze layer support tabs 42 prevent the interstitial layer internal channel wall sections 22C from falling out or becoming detached from the remaining structure of the interstitial layer 12C and provide registration stability for precisely aligning the interstitial layer internal channel wall sections 22C with the internal channel wall sections 22A and 22B of the first and second outer layers 12A and 12B when the respective layers are stacked together and bonded together. Additionally, as described above, the braze layer 30 is fabricated from a material having a lower melting temperature than the material from which the core interstitial layer 30 is fabricated. Thus, when layers 12A, 12B, and 12C are stacked, aligned, compressed, and heated, the support tabs 42 of the braze layers melt and diffuse into the compound microchannel(s) 18. In various examples, layers 12A, 12B, and 12C are stacked, aligned, compressed, and heated using a low pressure, such as 0-60 psi, for example 0-20 psi.
[0037]
[0051] Alternatively, in various embodiments in which both sides 12C' and 12C'' of the interstitial layer 12C are clad with a braze layer 30, as illustratively illustrated in FIG. 6B, the elongated slots 18C of the interstitial layer can be formed or cut (e.g., milled or etched) by first removing (e.g., milling or etching) the braze material of each of the braze layers 30 to form the elongated slots 18D of the braze layer on both sides 12C' and 12C'' of the interstitial layer 12C. Wide, shallow, elongated recesses having substantially the same pattern, path, array, or shape, and width as the shallow elongated recess(es) 18A and 18B can then be formed or cut (e.g., milled or etched) in each of the sides 12C' or 12C'' of the interstitial layer 12C such that opposing elongated recesses intersect, interconnect, and fluidly connect to form the elongated slot(s) 18C as described above. However, in such an embodiment, the elongated slot 18C is formed, created, or disposed through the interstitial layer(s) 12C to have a plurality of support tabs 34, as described above. In such an embodiment, the interstitial layer support tabs 34 prevent the interstitial layer interior channel wall section 22C from falling out or becoming detached from the remaining structure of the interstitial layer 12C and provide alignment stability for precisely aligning the interstitial layer interior channel wall section 22C with the interior channel wall sections 22A and 22B of the first and second outer layers 12A and 12B when the respective layers are stacked together and bonded together.
[0038]
[0052] As illustratively illustrated in FIG. 6C, in various embodiments, one or both of the outer layers 12A or 12B can be clad on one side with a layer 30 of brazing material. For example, as illustratively illustrated in the left composite microchannel 18 shown in FIG. 6C, in an embodiment in which one of the outer layers 12A or 12B is clad on one side with a layer 30 of brazing material and one of the faces 12C' or 12C'' of the interstitial layer 12C is clad with a layer 30 of brazing material, the interstitial layer elongated slot 18C can be formed by first removing (e.g., milling or etching) the brazing material of the brazing layer 30 disposed on the interstitial layer 12C to form the brazing layer elongated slot 18D. Then, interconnecting wide and shallow elongated recesses in both interstitial layer faces 12C' and 12C'' can be formed or cut (e.g., milling or etching) as described above with respect to FIG. 6B. Additionally, interstitial layer support tabs 34 will be formed within the resulting interstitial layer elongated slots 18C, as similarly described above with respect to FIG. 6B.
[0039]
[0053] Alternatively, in an embodiment where one of the outer layers 12A or 12B is clad on one side with a layer of braze material 30 and one of the faces 12C' or 12C'' of the interstitial layer 12C is clad with a layer of braze material 30, as illustratively illustrated in the right composite microchannel 18 shown in FIG. 6C, the interstitial layer elongated slot 18C can be formed by forming or cutting (e.g., milling or etching) a wide and deep interstitial layer elongated slot 18C in the non-braze clad face 12C' or 12C'', the interstitial layer elongated slot 18C having a depth equal to the thickness T of the interstitial layer 12C, as described above with respect to FIG. 6A. Additionally, a braze layer elongated slot 18D with a support tab 42 would be formed in the braze layer 30 of the braze clad face 12C' or 12C'', as also described above with respect to FIG. 6A.
[0040]
[0054] Alternatively, in an embodiment in which both outer layers 12A or 12B are clad on one side with a layer of braze material 30 and the interstitial layer 12C is not clad on either side 12C' or 12C'' with a layer of braze material 30, as illustratively illustrated in the intermediate composite microchannel 18, the interstitial layer elongated slots 18C may be formed by forming or cutting (e.g., milling or etching) interconnecting wide and shallow elongated recesses in both interstitial layer sides 12C' and 12C'', as described above with respect to FIG. 6B. Additionally, interstitial layer support tabs 34 may be formed in the resulting interstitial layer elongated slots 18C, as also described above with respect to FIG. 6B.
[0041]
[0055] 7, as described above, the multi-layer microchannel heat transfer body 12 can include one or more interstitial layers, plates, stratums, or substrates 12C disposed between and bonded to a first outer layer 12A and a second outer layer 12B. For example, as shown in FIG 7, in various embodiments, the multi-layer microchannel heat transfer body 12 can include a first outer layer, plate, stratum, or substrate 12A, a second outer layer, plate, stratum, or substrate 12B, and a plurality of interstitial layers, plates, stratums, or substrates 12C disposed between and bonded to the first outer layer 12A and the second layer 12B.
[0042]
[0056] In various instances of such an embodiment, the braze layer 30 can be separate from the first outer layer 12A, the second outer layer 12B, and the plurality of interstitial layers 12C, as described above with respect to Figure 5. Additionally, the compound microchannel(s) 18 (e.g., the elongated recesses 18A and 18B in the first and second outer layers, the elongated slots 18C in the interstitial layers, the elongated slots 18D in the braze layer, the support tabs 34 in the interstitial layers, and the support tabs 42 in the braze layer) can be formed as described above with respect to Figures 3A, 3B, 4A, 4B, 4C, and 5. Furthermore, the body 12 having the hermetically sealed compound microchannel(s) 18 can be formed by stacking, aligning, compressing, and heating the first and second outer layers 12A and 12B, the plurality of interstitial layers 12C, and the braze layer 30, as described above with respect to Figures 1-6C.
[0043]
[0057] In various other instances of such embodiments, one or more of the first outer layer 12A, and / or the second outer layer 12B, and / or the interstitial layer 30 can be fabricated to include (i.e., be clad with) the braze layer 30 disposed on one or more surfaces thereof, as described above with respect to Figures 6A, 6B, and 6C. Additionally, the compound microchannel(s) 18 (e.g., the elongated recesses 18A and 18B of the first and second outer layers, the elongated slots 18C of the interstitial layer, the elongated slots 18D of the braze layer, the support tabs 34 of the interstitial layer, and the support tabs 42 of the braze layer) can be formed as described above with respect to Figures 4A, 4B, 4C, 6A, 6B, and 6C. Furthermore, the body 12 having the hermetically sealed composite microchannel(s) 18 can be formed by stacking, aligning, compressing and heating the first and second outer layers 12A and 12B, the multiple interstitial layers 12C, and the braze layer 30, as described above with respect to Figures 1-6C.
[0044]
[0058] 8, in various embodiments, the multi-layer microchannel body 12 of the multi-layer microchannel heat transfer device 10 can include multiple interstitial layers 12C with elongated slots 18C, where the interstitial layer(s) 12C are disposed between a first outer layer 112A and a second outer layer 112B, and it is assumed that the first and second outer cover layers 112A and 112B are devoid of elongated recesses 18A and 18B. Hence, in such embodiments, the composite microchannel(s) 18 are formed by aligning and stacking the elongated slots 18C of the interstitial layers. Additionally, the braze layer 30 can be freestanding or disposed on one or more of the first and second outer cover layers 112A and 112B and the interstitial layers 12C. Furthermore, the elongated slots 18C of the interstitial layers, the elongated slots 18D of the braze layer, the support tabs 34 of the interstitial layers, and / or the support tabs 42 of the braze layer can be formed as described above with respect to FIGS. 3A-6C. Furthermore, a body 12 having a hermetically sealed composite microchannel(s) 18 can be formed by stacking, aligning, compressing and heating multiple interstitial layers 12C and braze layers 30 as described above with respect to Figures 1-6C.
[0045]
[0059] Although various embodiments of the multilayer microchannel heat transfer device 10 have been illustratively described as being fabricated utilizing either a free-standing braze layer 30 or a cladding braze layer 30 (i.e., one or more of the first and second outer layers 12A and 12B and / or interstitial layer(s) 12C have the braze layer(s) 30 disposed thereon as a cladding), these illustrative embodiments are not limiting. In particular, it is envisioned that any of the various illustrative embodiments described herein may be fabricated utilizing a combination of one or more free-standing braze layers 30 and one or more cladding braze layers 30.
[0046]
[0060] It should also be noted that the various layers of each of the various illustrative embodiments of the multi-layer microchannel heat transfer device 10 described herein can be made from a wide range of materials and generally in any shape and size desired to meet the specifications of the heat source(s) and heat sink(s) or exhaust area(s) of a given application (e.g., the respective size of the device 10, heat load, heat flux, location, temperature, gravitational field, thermal expansion coefficient requirements, etc.). Additionally, the patterns, paths, arrays, or shapes of the compound microchannel(s) 18 can form closed loops (e.g., circular) or can be sealed at each end to form open loops (e.g., serpentine or linear). Furthermore, the patterns, paths, arrays, or shapes of the compound microchannel(s) 18 can travel in two dimensions (i.e., the xy plane or the r-θ plane) or in all three physical dimensions (i.e., xyz and / or r-θ-h). Still further, the cross-sectional shape of the compound microchannel(s) 18 can generally have any desired shape, and the length of the compound microchannel can vary (e.g., from less than 1 cm to more than 10 m), so long as the compound microchannel(s) 18 maintains the capillary effect that causes the working fluid inside the channel volume to disperse into discrete liquid "plugs" and vapor "bubbles." Still further, the working fluid can be any desired working fluid selected based on its thermophysical properties (e.g., vapor pressure, latent heat, specific heat, density, surface tension, critical temperature, pour point, viscosity, etc.) and compatible with the material(s) used to form the body and channels.
[0047]
[0061] The description herein is merely exemplary in nature, and as such, variations that do not depart from the gist of what is described are intended to be within the scope of the present teachings. Moreover, while the foregoing description and associated drawings describe example embodiments in the context of certain example combinations of elements and / or functions, it will be appreciated that alternative embodiments may provide different combinations of elements and / or functions without departing from the scope of the present disclosure. Such variations and alternative combinations of elements and / or functions should not be considered as departures from the spirit and scope of the present teachings.
Claims
1. 1. A multi-layer microchannel heat transfer device, comprising: The multi-layer body includes: a first outer layer having at least one micro-sized first elongated recess formed therein; a second outer layer including at least one second micro-sized elongated recess formed in the second outer layer; at least one gap layer having at least one micro-sized elongated gap slot formed therethrough; wherein the first outer layer, the second outer layer, and at least one of the interstitial layers are stacked and bonded together with the at least one interstitial layer disposed between the first outer layer and the second outer layer, whereby the at least one first elongated recess in the first outer layer, the at least one second elongated recess in the second outer layer, and the at least one elongated interstitial slot in the at least one interstitial layer are aligned and combined to form at least one deep and narrow complex microchannel having a high height-to-width aspect ratio disposed within and enclosed within the resulting multi-layer body.
2. The multi-layer body further comprises a plurality of braze layers, each braze layer comprising at least one elongated slot, each braze layer comprising: disposed between the first outer layer and an adjacent one of the at least one interstitial layer; disposed between the second outer layer and an adjacent one of the at least one interstitial layer; When the at least one interstitial layer comprises a plurality of interstitial layers, the at least one interstitial layer is disposed between adjacent interstitial layers. The device of claim 1 , further comprising one of the following:
3. 3. The device of claim 2, wherein the brazing layer is separate and independent from the first outer layer, the second outer layer, and the at least one interstitial layer before the first outer layer, the second outer layer, and the at least one interstitial layer are stacked and joined together.
4. The device of claim 3 , wherein the elongated slot of at least one of the interstitial layers comprises a plurality of interstitial layer support tabs extending across the elongated slot of the at least one interstitial layer.
5. The device of claim 4 , wherein the elongated slot of at least one of the braze layers comprises a plurality of braze layer support tabs extending across the elongated slot of the at least one of the braze layers.
6. The device of claim 5 , wherein at least one of the interstitial layer elongated slots comprises opposing intersecting and fluidly connected micro-sized elongated recesses.
7. 3. The device of claim 2, wherein before the first outer layer, the second outer layer, and at least one of the interstitial layers are stacked and joined together, at least one surface of at least one of the first outer layer, the second outer layer, and at least one of the interstitial layers has one of the brazing layers disposed thereon such that each of the surfaces is clad with a respective one of the brazing layers.
8. at least one interstitial layer elongated slot having a plurality of interstitial layer support tabs extending across said at least one interstitial layer elongated slot; the at least one braze layer elongated slot includes a plurality of braze layer support tabs extending across the at least one braze layer elongated slot; The device of claim 7, wherein the at least one of
9. The device of claim 8 , wherein at least one of the interstitial layer elongated slots comprises opposing intersecting and fluidly connected micro-sized elongated recesses.
10. The device of claim 8 , wherein the elongated slots of at least one of the interstitial layers comprise micro-sized elongated channels having a depth equal to a thickness T of the at least one interstitial layer.
11. 1. A method of fabricating a multi-layer microchannel heat transfer device, the method comprising: forming at least one micro-sized first elongated recess in a first substrate to fabricate a first outer layer; forming at least one second micro-sized elongated recess in a second substrate to fabricate a second outer layer; forming at least one micro-sized elongated gap slot in at least one gap substrate to fabricate at least one gap layer; disposing at least one interstitial layer between the first outer layer and the second outer layer to form a multi-layer body; wherein the first outer layer, the second outer layer, and at least one of the interstitial layers are stacked and bonded together so that the at least one first elongated recess in the first outer layer, the at least one second elongated recess in the second outer layer, and the at least one elongated interstitial slot in the at least one interstitial layer are aligned and combined to form at least one deep and narrow complex microchannel having a high height-to-width aspect ratio disposed within and enclosed within the multi-layer body.
12. The method comprises: providing a plurality of braze layers, each braze layer comprising at least one elongated slot; disposing one of the braze layers between the first outer layer and an adjacent one of the at least one interstitial layer; disposing one of the braze layers between the second outer layer and an adjacent one of the at least one interstitial layer; when the at least one gap layer comprises a plurality of gap layers, disposing one of the plurality of brazing layers between adjacent gap layers; and The method of claim 11 further comprising:
13. 13. The method of claim 12, wherein the braze layer is separate and independent from the first outer layer, the second outer layer, and the at least one interstitial layer before the first outer layer, the second outer layer, and the at least one interstitial layer are stacked and joined together.
14. 14. The method of claim 13, wherein forming at least one elongated gap slot in at least one gap substrate to fabricate at least one gap layer comprises forming a plurality of gap layer support tabs extending across the at least one elongated gap slot.
15. 15. The method of claim 14, wherein providing a plurality of said braze layers comprises forming an elongated slot of at least one of said braze layers to include support tabs of a plurality of braze layers extending across said elongated slot of at least one of said braze layers.
16. Forming at least one elongated gap slot in the at least one gap substrate to fabricate the at least one gap layer includes: forming at least one first micro-sized elongated recess in a first surface of at least one of the interstitial layers; forming at least one opposing second micro-sized elongated recess in a second surface of at least one of said interstitial layers such that the first and second micro-sized elongated recesses intersect and fluidly connect to form at least one of said interstitial layers, said interstitial layers being elongated. The method of claim 15 comprising:
17. 13. The method of claim 12, wherein before the first outer layer, the second outer layer, and at least one of the interstitial layers are stacked and joined together, at least one surface of at least one of the first outer layer, the second outer layer, and at least one of the interstitial layers has one of the braze layers disposed thereon such that each of the surfaces is clad with a respective one of the braze layers.
18. forming at least one elongated gap slot in at least one gap substrate to fabricate at least one gap layer, comprising forming a plurality of gap layer support tabs extending across the at least one elongated gap slot; providing a plurality of said braze layers comprises forming an elongated slot of at least one of said braze layers to include a plurality of braze layer support tabs extending across said elongated slot of at least one of said braze layers; 20. The method of claim 17, wherein the at least one of
19. Forming at least one elongated gap slot in the at least one gap substrate to fabricate the at least one gap layer includes: forming at least one first micro-sized elongated recess in a first surface of at least one of the interstitial layers; forming at least one opposing second micro-sized elongated recess in a second surface of at least one of said interstitial layers such that the first and second micro-sized elongated recesses intersect and fluidly connect to form at least one of said interstitial layers, said interstitial layers being elongated.
20. The method of claim 18 comprising:
20. 20. The method of claim 18, wherein forming at least one elongated gap slot in at least one gap substrate to fabricate at least one gap layer comprises forming at least one micro-sized elongated channel having a depth equal to a thickness T of the at least one gap layer.