Tube-in-tube heat pipe

Abstract

This invention discloses a tube-in-tube heat pipe. A tube-in-tube heat pipe may include an outer tube having a cylindrical shape extending from a first end to a second end and having an outer tube chamber. The outer tube is closed at the first end and the second end. The tube-in-tube heat pipe may further include an inner tube having a cylindrical shape and disposed within the outer tube. The inner tube includes a porous material surrounding an internal volume. The inner tube is disposed within the outer tube chamber.

Description

Technical Field

[0001] This invention relates to a tube-in-tube heat pipe technology, which is mainly used to improve the thermal management efficiency of electronic devices, and is particularly suitable for compact and high-performance mobile technologies. Prior Technology

[0002] As electronic devices achieve greater integration and higher performance, thermal management becomes increasingly important. Some new mobile technologies face particularly challenging thermal management scenarios due to their small size and high-performance requirements. Summary of the Invention

[0003] Various tube-in-tube heat pipes have been disclosed. For example, one tube-in-tube heat pipe includes an outer tube having a cylindrical shape extending from a first end to a second end, the outer tube having a hollow interior, the outer tube being closed at the first end and the second end; and an inner tube having a cylindrical shape extending from a first end to a second end, the inner tube being disposed within the hollow interior of the outer tube, the inner tube including a porous material surrounding an internal volume filled with liquid, the porous material preventing vapor permeation into the internal volume and substantially blocking liquid flow.

[0004] Any tube-in-tube heat pipe disclosed in this document may include an inner tube and / or an outer tube comprising a porous inorganic material. For example, the porous inorganic material may include porous glass, porous copper, or porous ceramic. For example, the porous inorganic material may be formed by dealloying the inorganic material and / or sintering micro / nanoparticles into the inorganic material.

[0005] For example, any tube-in-tube heat pipe disclosed in this document may include an inner tube comprising an organic material coated with an inorganic material.

[0006] For example, any tube-in-tube heat pipe disclosed in this document may include an inner tube, which may include a porous outer layer with a mesh and / or a porous inner layer disposed within the porous outer layer.

[0007] For example, any tube-in-tube heat pipe disclosed in this document may include a gap between the porous outer layer and one of the inner surfaces of the outer tube, the gap having an average gap width of less than about 0.08 mm. For example, the porous outer layer may enclose the porous inner layer, and the gap between one of the outer surfaces of the porous inner layer has an average gap width of less than about 0.08 mm. For example, the porous outer layer may include a plurality of first plurality of wires, and the porous inner layer may include a plurality of second plurality of wires, wherein the cross-sectional dimension of the first wires is half the cross-sectional dimension of the second wires. For example, either or both of the porous outer layer and the porous inner layer may include a portion having microparticles or nanoparticles.

[0008] For example, any tube-in-tube heat pipe disclosed in this document may include an inner tube comprising a porous polymer formed by dissolving a copolymer, track etching, or spin-casing.

[0009] The disclosed tube-in-tube heat pipe includes an outer tube having a cylindrical shape extending from a first end to a second end, the outer tube having a hollow interior, and the outer tube being closed at the first and second ends; and an inner tube having a cylindrical shape extending from a first end to a second end, the inner tube being disposed within the hollow interior of the outer tube, the inner tube comprising a porous material surrounding an inner volume. For example, the tube-in-tube heat pipe may be filled with a liquid. For example, a liquid channel is formed between the outer surface of the inner tube and the inner surface of the outer tube. For example, a gap between the outer surface of the inner tube and the inner surface of the outer tube prevents vapor bubbles from blocking the entire liquid flow in the liquid channel.

[0010] For example, any tube-in-tube heat pipe disclosed in this document may include an inner tube and / or an outer tube comprising a porous inorganic material. For example, the porous inorganic material may include porous glass, porous copper, or porous ceramic. For example, the porous inorganic material may be formed by dealloying the inorganic material and / or sintering micron / nano particles into the inorganic material.

[0011] For example, any tube-in-tube heat pipe disclosed in this document may include an inner tube comprising an organic material coated with an inorganic material.

[0012] For example, any tube-in-tube heat pipe disclosed in this document may include an inner tube that may include a porous outer layer and a porous inner layer disposed within the porous outer layer. For example, the gap between the porous outer layer and an inner surface of the outer tube may have an average gap width of less than about 0.08 mm. For example, the porous outer layer encloses the porous inner layer, and the gap between the outer layer and an outer surface of the porous inner layer has an average gap width of less than about 0.08 mm. For example, the porous outer layer may include a plurality of first wires, and the porous inner layer includes a plurality of second wires, wherein the cross-sectional dimension of the first wires is half the cross-sectional dimension of the second wires. For example, either or both of the porous outer layer or the porous inner layer may include a component having microparticles or nanoparticles along the length of the inner tube.

[0013] For example, any tube-in-tube heat pipe disclosed in this document may include an inner tube comprising a porous polymer formed by dissolving a copolymer, track etching, or rotational molding. Simple Explanation of the Diagram

[0014] Figure 1A is a vertical cross-sectional view of an example of a tube-in-tube heat pipe; Figure 1B is a cross-sectional view of the tube-in-tube heat pipe shown in Figure 1A along section AA; Figure 2A is a vertical cross-sectional view of another example of a tube-in-tube heat pipe; Figure 2B is a cross-sectional view of the tube-in-tube heat pipe shown in Figure 1A along section AA; Figure 3A is a vertical cross-sectional view of a layered-mesh heat pipe with one or two layered meshes; Figure 3B is a cross-sectional view of the layered-mesh heat pipe shown in Figure 3A along section AA; Figure 3C is a cross-sectional view of the layered-mesh heat pipe shown in Figure 3A along section BB; Figure 3D is a cross-sectional view of a coarse mesh; Figure 3E is a cross-sectional view of a fine mesh. Figure 4A is a vertical cross-sectional view of an example of a layered mesh heat pipe with one or two layers of mesh; Figure 4B is a cross-sectional view of the layered mesh heat pipe shown in Figure 4A along section AA; Figure 4C is a cross-sectional view of the layered mesh heat pipe shown in Figure 4A along section BB; Figure 5 is an example of a tube-in-tube heat pipe having wicks including regions with different porosities; Figure 6 is a two-dimensional structural diagram of a tube-in-tube heat pipe; Figure 7A is an end view of a planar tube-in-tube heat pipe containing a plurality of wicks with multiple inner tubes; Figure 7B is a top view of a planar tube-in-tube heat pipe containing a plurality of wicks with multiple inner tubes; Figure 8 is a top view of a planar tube-in-tube heat pipe containing a plurality of wicks that converge at one end to a local heat source and at the other end to a manifold. The core is coupled to the wick; Figure 9 is a schematic diagram of a tube-in-tube heat pipe, in which the inner tube contains microwires wires and the inner tube is in contact with the outer tube; Figure 10A is a schematic diagram of a tube-in-tube heat pipe in a compressed state; Figure 10B is a schematic diagram of a tube-in-tube heat pipe in a stretched state. Implementation

[0015] This document discloses various examples of tube-in-tube heat pipes. A heat pipe includes a liquid within a porous wick and a vapor disposed within a hermetically sealed cavity. The liquid and vapor are typically in thermal equilibrium. The cavity is typically formed by a cylindrical pipe closed at both ends. When heat is applied to a region of the heat pipe, the liquid evaporates; the vapor is propelled through the vapor cavity to a cooler region due to a difference in saturation pressure. As it moves within the vapor cavity, the vapor can carry heat from the hotter region to the cooler region via convection. When the vapor reaches the cooler region, it condenses and releases heat into the environment through that region. The liquid is drawn back to the hotter region by capillary forces within the wick.

[0016] This document discloses a tube-in-tube heat pipe comprising an inner tube disposed within a cylindrical tube. For example, the inner tube may comprise a porous hollow fiber, a copper tube, a glass tube, a fiber, a copper braid, or a glass braid. For instance, the fiber used in this document may comprise a braid such as a copper braid or a glass braid.

[0017] Figure 1A is a vertical cross-sectional view of an example of a tube-in-tube heat pipe 100. Figure 1B is a cross-sectional view of the tube-in-tube heat pipe 100 along section AA, which is perpendicular to the longitudinal axis of the tube-in-tube heat pipe 100.

[0018] For example, the tube-in-tube heat pipe 100 includes an outer tube 105, a first inner tube 130, and a second inner tube 140. The outer tube 105 may have a cylindrical shape and / or may be surrounded by a polymer cladding 110, which may be disposed on or cover the outer surface of the outer tube 105. The first inner tube 130 may include a first internal volume 131. The second inner tube 140 may include a second internal volume 141.

[0019] For example, the outer tube 105 may comprise any type of material, such as copper, aluminum, steel, stainless steel, brass, zinc, glass, etc. The outer tube 105 may be airtightly sealed at a first end 120 and a second end 121. The first end 120 and / or the second end 121 may include a cap, a crimp, a weld, a pinch-seal, a diffusion bond, a solder, a brazing, a weld, a glass seal, etc.

[0020] The outer tube 105 may enclose (or fill) a fluid within the internal volume 115, which may include, for example, water, organic solvents, acetone, any ketones, methanol, any alcohols, pentane, other hydrocarbons, etc. For example, the fluid may also include an organic dielectric fluid such as hexane. Alternatively, the fluid may include a synthetic dielectric fluid such as hydrofluoroether or hydrofluoroketone, or any other synthetic refrigerant.

[0021] For example, the tube-in-tube heat pipe 100 may include a passivation layer 125 on the inner wall of the outer tube 105. For example, the passivation layer 125 can prevent reaction between the material of the outer tube 105 and the internal fluid. For example, the passivation layer 125 may include a ceramic, such as aluminum oxide, silicon oxide, silicon nitride, titanium oxide, etc. For example, the passivation layer 125 can be deposited by methods such as sol-gel, electroplating, or atomic layer deposition.

[0022] Although two inner tubes, a first inner tube 130 and a second inner tube 140, are shown in the tube-in-tube heat pipe 100, any number of inner tubes can be used. The first inner tube 130 and / or the second inner tube 140 may have a cylindrical shape.

[0023] For example, the first inner tube 130 and / or the second inner tube 140 may include a hollow tube having a first internal volume 131. Liquid may fill and / or flow through the first internal volume 131 of the first inner tube 130 and / or the second inner tube 140. The first internal volume 131 may be a liquid channel. For example, the tubular body of the first inner tube 130 and / or the second inner tube 140 may include porous glass, glass braid, glass fiber, extruded glass, coarse glass mesh, fine glass mesh, etc. For example, the tubular body of the first inner tube 130 and / or the second inner tube 140 may include porous copper, copper braid, copper fiber, extruded copper, coarse copper mesh, fine copper mesh, etc.

[0024] For example, the first inner tube 130 and / or the second inner tube 140 may include a cap, a crimping portion, a welding portion, a clamping sealing portion, a diffusion keying portion, solder, a copper soldering portion, a welding portion, a glass sealing portion, etc. at one or both ends of the first inner tube 130 and / or the second inner tube 140.

[0025] For example, the first inner tube 130 and / or the second inner tube 140 may include a porous material. For example, the first inner tube 130 and / or the second inner tube 140 may include a porous metal, such as copper, aluminum, zinc, etc. For example, the first inner tube 130 and / or the second inner tube 140 may include a metal tube (e.g., copper, aluminum, zinc, etc.) whose tube wall is made porous through acid treatment (e.g., dealloying). For example, the first inner tube 130 and / or the second inner tube 140 may include a porous polyamide membrane, a blasted polyamide membrane to form pores, a track-etched polyamide membrane, etc. For example, the first inner tube 130 and / or the second inner tube 140 may include a polymer with pores or a copper-coated polymer. For example, the first inner tube 130 and / or the second inner tube 140 may include porous copper, copper braid, copper fiber, extruded copper, coarse copper mesh, fine copper mesh, etc.

[0026] For example, the first inner tube 130 and / or the second inner tube 140 may include a plurality of holes. For example, the plurality of holes may be formed by etching, such as by a patterned mask. For example, the plurality of holes may be formed as part of a weave, mesh, fiber, etc. For example, the plurality of holes may be formed by dealloying or blasting. For example, the plurality of holes may be small enough to prevent vapor permeation into the internal volume 131 of the first inner tube 130 and / or the second inner tube 140. For example, the pore size of the plurality of holes may be less than or equal to about 10,000 nanometers (nm), for example, less than or equal to or about 100 nm, 300 nm, 1,000 nm, 3,000 nm, 7,000 nm, etc.

[0027] For example, the first inner tube 130 and / or the second inner tube 140 may have a substantially homogenous radial cross-section.

[0028] For example, the inner diameter of the outer tube 105 may be equal to or greater than twice the outer diameter of the first inner tube 130 and / or the outer diameter of the second inner tube 140.

[0029] For example, the inner diameter of the outer tube 105 can be less than or equal to approximately 0.25, 0.5, 0.75, 0.95, 1.93, 2.90, 3.90, or 4.90 millimeters (mm), for example, less than or equal to approximately 4.8 mm. For example, the outer diameter of the outer tube 105 can be less than or equal to approximately 5.0 mm, for example, less than or equal to approximately 0.35 mm, 0.65 mm, 1.0 mm, 2.0 mm, 3.0 mm, 4.0 mm, or 5 mm. For example, the inner diameter of the first inner tube 130 and / or the second inner tube 140 can be less than or equal to approximately 0.25 mm, for example, less than or equal to approximately 0.025 mm, 0.050 mm, or 0.100 mm. For example, the outer diameter of the first inner tube 130 and / or the second inner tube 140 may be less than or equal to about 0.5 mm, for example, less than or equal to about 0.050 mm, 0.075 mm, 0.150 mm, etc.

[0030] For example, the first inner tube 130 and / or the second inner tube 140 may include polyethersulfone (PES) and / or modified-polyethersulfone (mPES). For example, the PES and / or mPES may be formed by a spinning process, such as wet spinning, dry spinning, wet-dry jet spinning, melt spinning, etc.

[0031] For example, the first inner tube 130 and / or the second inner tube 140 may comprise a polymer, such as polyimide, polyester, polycarbonate, etc. The pores in the first inner tube 130 and / or the second inner tube 140 may be formed by dissolving a copolymer, track etching, rotational molding, etc. The first inner tube 130 and / or the second inner tube 140 may comprise a hollow fiber tangential flow filter. For example, a fiber tangential flow filter can be a filter developed to separate impurities from any liquid passing through it. For example, the first inner tube 130 and / or the second inner tube 140 may be coated with ceramic using atomic layer deposition (ALD), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), etc.

[0032] As another example, a tube-in-tube heat pipe 100 may include a plurality of inner tubes bundled together. Each of the plurality of inner tubes may include any example of the first inner tube 130 described herein. The plurality of inner tubes may or may not be bonded together. Each of the plurality of inner tubes may or may not be porous. For example, one or more of the plurality of inner tubes may be sealed at intermediate lengths along the longitudinal length of the inner tube, which provides a path for liquid to flow between the inner tubes through the inner tube walls. For example, each of the plurality of inner tubes may be sealed with an external porous wall, and liquid may flow therethrough.

[0033] For example, bundled multiple inner tubes can be formed using optical fibers (e.g., photonic crystal fibers); for example, a preform with a tubular shape can be stretched to a thickness of one micrometer while retaining the characteristics of the preform. For example, fibers can be formed by spinning from an extruder with multiple nozzles.

[0034] A tube-in-tube heat pipe 100 may be partially flattened into an oval or oblong shape. For example, this can reduce the thickness of the tube-in-tube heat pipe 100 and / or increase its flexibility. The tube-in-tube heat pipe 100 may be flattened along its entire length or along certain or more regions of its longitudinal length. For example, the flattened portions of the tube-in-tube heat pipe 100 may have different thicknesses. The flattened regions of the tube-in-tube heat pipe 100 may be placed close to a heat source. The flattened portions may be flattened such that the inner wall of the outer tube 105 contacts the outer surface of the first inner tube 130.

[0035] Figure 2A is a vertical cross-sectional view of another example of a tube-in-tube heat pipe 200, wherein the cross-section is parallel to the tube axis. Figure 2B is a cross-sectional view of the tube-in-tube heat pipe 200 shown in Figure 2A along section AA, wherein the cross-section is perpendicular to the tube axis.

[0036] For example, the tube-in-tube heat pipe 200 may include an inner tube 230, which may or may not be connected to the inner wall of the outer tube 105. Vapor can be transported through the internal volume 231 of the inner tube 230. Liquid can be transported in the space 240 between the outer tube 105 and the inner tube 230. For example, the inner tube 230 may include a mesh. For example, the inner tube 230 may include a tube made of braided material, such as one or both of a fine mesh 351 and a coarse mesh 352 as shown in Figures 3A and 4A.

[0037] Figure 3A shows a vertical cross-section of a tube-in-tube heat pipe 300, which includes a coarse mesh 352 and a fine mesh 351, stacked within an outer tube 305. Figure 3B is a cross-sectional view of the tube-in-tube heat pipe 300 shown in Figure 3A along section AA. Figure 3C is a cross-sectional view of the tube-in-tube heat pipe 300 shown in Figure 3A along section BB.

[0038] For example, a tube-in-tube heat pipe 300 may include a coarse mesh 352 and a fine mesh 351. In one embodiment, the coarse mesh 352 serves as a porous outer layer, and the fine mesh 351 is disposed within the porous outer layer as a porous inner layer. For example, the strands of the coarse mesh 352 and / or the strands of the fine mesh 351 may be asynchronous relative to each other, such that the holes or openings in the coarse mesh 352 are not aligned with the holes or openings in the fine mesh 351. Although two mesh layers are shown, any number of mesh layers can be used.

[0039] The coarse mesh 352 can be formed and / or woven into a tube shape. The fine mesh 351 can also be formed and / or woven into a tube shape. The coarse mesh 352 can be configured and / or cover the outside of the fine mesh 351 (or vice versa) to create a double-layer mesh. The double-layer mesh (e.g., including a layer of fine mesh 351 and a layer of coarse mesh 352) can be configured inside the outer tube 305. For example, a first layer of mesh can cover a second layer of mesh.

[0040] The outer tube 305 may include any example of the outer tube 105 described in this document. The outer tube 305 may be crimped or sealed at both ends.

[0041] Figure 3E is a cross-sectional view of an example fine strand 361, which can be woven together to form a fine mesh 351. A fine strand 361 may include a ribbon of multiple individual fine strands 366 or an extruded group of multiple fine strands 366.

[0042] For example, a filament 361 may include a plurality of filaments 366, for example, each filament 361 may include 1 to 12 filaments 366. For example, each filament 366 may have a diameter from 0.001 to 0.1 mm or greater, for example, less than about 0.03 mm.

[0043] For example, each filament 361 may include glass, copper, or other inorganic or organic materials.

[0044] For example, a fine mesh 351 can be woven into a mesh composed of fine threads 361.

[0045] For example, the fine mesh 351 can have a mesh number from #5, #10, #15, #20, #25, #30 or higher, with corresponding pitches of 5.08 mm, 2.54 mm, 1.69 mm, 1.27 mm, 1.02 mm, and 0.85 mm, respectively. The mesh number is the number of openings per inch. The pitch is the distance between the midpoints of two adjacent openings in the mesh. In some cases, the diameter of the fine wire 366 and the mesh number of the fine mesh 351 are two considerations when designing a tube-in-tube heat pipe. For example, a small wire diameter and a large mesh number can be used. This can be done, for example, to create smaller pore sizes, which may be beneficial for higher capillary pressure.

[0046] Figure 3D is a cross-sectional view of an example coarse strand 362, which can be woven together to form a coarse mesh 352. The coarse strand 362 may include a ribbon of multiple individual coarse wires 367 or an extruded group of multiple coarse wires 367.

[0047] For example, a coarse wire 362 may include a plurality of coarse wires 367, for example, each coarse wire 362 may include 1 to 12 coarse wires 367. For example, each coarse wire 367 may have a diameter from 0.001 to 0.1 mm or greater, for example, less than about 0.08 mm. For example, each coarse wire 367 of a coarse wire 362 may have a diameter smaller than the diameter of a coarse wire 367 of a coarse mesh 352. Each coarse wire 367 of a coarse mesh 352 may have a cross-sectional dimension (e.g., diameter) that is approximately twice the cross-sectional dimension of a single wire 367 of a fine mesh 351.

[0048] For example, each filament 362 may include glass, copper, or other inorganic or organic materials. For example, a mesh 352 may be woven from one or more filaments 362.

[0049] For example, the coarse mesh 352 can have a mesh count of #5, #10, #15, #20, #25, #30 or higher, corresponding to spacings of 5.08 mm, 2.54 mm, 1.69 mm, 1.27 mm, 1.02 mm, and 0.85 mm, respectively. The mesh count is the number of openings per inch. The spacing is the distance between the midpoints of two adjacent openings in the mesh. In some cases, the diameter of the coarse wire 367 and the mesh count of the coarse mesh 352 are two considerations when designing a tube-in-tube heat pipe. For example, a small wire diameter and a large mesh count can be used. This can be done to create a smaller aperture, which may be beneficial for higher capillary pressure.

[0050] In one example, coarse mesh 352 can have a mesh number of 25, and fine mesh 351 can have a mesh number of 15.

[0051] The fine mesh 351 can be made (or woven) into a tube shape, forming a plurality of diamond-shaped openings 371 between the weaves of the fine mesh 351. The coarse mesh 352 can be made (or woven) into a tube shape, forming a plurality of diamond-shaped openings 372 between the weaves of the coarse mesh 352. In some areas, the openings 371 in the fine mesh 351 and the openings 372 in the coarse mesh 352 can be aligned, while in other areas the openings may not be aligned. The position of these openings in the mesh can be random, and the alignment between the fine mesh 351 and the coarse mesh 352 may not be aligned during manufacturing. The size and number of openings 371 and 372 depend on the mesh count.

[0052] For example, fine mesh 351 can separate vapor and liquid transport channels. For example, coarse mesh 352 and the gap between coarse mesh 352 and the outer tube 305 can form a liquid transport channel. Some openings 371 in fine mesh 351 may be partially blocked by the threads of coarse mesh 352, or the openings in fine mesh 351 may be aligned or misaligned with the openings in coarse mesh 352. If an opening 371 is substantially blocked (or, for example, misaligned), the vapor-liquid interface can be maintained by surface tension, where the radius of the interface is related to the pressure difference between the vapor and liquid.

[0053] If an opening 371 is not substantially blocked (or, for example, aligned), a separate vapor and liquid transport channel may not be formed. For example, vapor may enter the gap 381 from the vapor channel 354 through the opening 371, and / or form bubbles during liquid transport. For example, any such bubbles may block part of the liquid transport channel within the gap 381. However, the gap 381 between the coarse mesh 352 and the inner wall of the outer tube 305 can limit the size of the bubbles and mitigate the problem of bubbles blocking the liquid transport channel in the gap 381. For example, the gap 381 can be large enough for efficient liquid flow and small enough to limit bubble growth outside the opening 372 of the coarse mesh 352.

[0054] Since each coarse wire 362 of each coarse mesh 352 is not flat, the gap 381 may vary along the length of a portion of the inner wall of the outer tube 305. The gap 381 can be defined by the diameter of the coarse wire 367 of each coarse wire 362 and the inner wall of the outer tube 305. Therefore, the width of the gap 381 may vary along the length of the coarse wire 362 and / or along the length of the coarse mesh 352. For example, the average width of the gap 381 may be smaller than the diameter of the coarse wire 367. Along substantially the entire length of the coarse wire 362 and / or along the length of the coarse mesh 352, the gap 381 may have an average width from 0.0 mm to 0.08 mm.

[0055] In some cases, as the width of gap 381 decreases, the resistance to liquid flow within gap 381 may increase, and as the width of gap 381 increases, the resistance to liquid flow within gap 381 may decrease. In such cases, the likelihood of bubbles entering other rhomboid openings increases and decreases as the width of gap 381 increases and decreases, respectively. The diameter of the thick wire 367, which affects the width of gap 381, can be one of the many other important factors to consider in tube-in-tube design.

[0056] Figure 4A shows a vertical cross-sectional view of a layered mesh heat pipe 400 with one or two layers of mesh. Figure 4B is a cross-sectional view of the layered mesh heat pipe 400 shown in Figure 4A along section AA. Figure 4C is a cross-sectional view of the layered mesh heat pipe 400 shown in Figure 4A along section BB.

[0057] In this example, coarse mesh 352 is located inside fine mesh 351. An inner tube 490 can be included within the coarse mesh 352 and fine mesh 351. An internal gap 482 can exist between the coarse mesh 352 and the outer wall of the inner tube 490. An external gap 480 can exist between the fine mesh 351 and the inner wall of the outer tube 305. The internal gap 482 can be a liquid passage, and the external gap 480 can be a vapor passage, wherein the two mesh layers (e.g., fine mesh 351 and coarse mesh 352) are located between the two passages. Liquid can flow within the internal gap 482.

[0058] The tube-in-tube heat pipe 100, tube-in-tube heat pipe 200, and / or tube-in-tube heat pipe 300 may be substantially RF transparent. For example, the outer tube 105 (or outer tube 305) may include glass, which may be coated with a polymer. For example, the polymer may improve the flexibility and / or robustness of the glass. Any inner tube (e.g., first inner tube 130, second inner tube 140, inner tube 230, inner tube 490, fine mesh 351, and / or coarse mesh 352) may include porous glass, porous ceramic, dielectric material, or other inorganic material. For example, thermal vias may pass through any inner tube. This may, for example, reduce evaporator thermal resistance. For example, any first inner tube may include porous glass or porous ceramic formed by dealloying glass or ceramic and / or sintering micron / nano particles into glass or ceramic.

[0059] For example, any first inner tube can be bonded to the inside of an outer tube. For example, bonding particles can be disposed between the inside of the outer tube and the outside of the inner tube. For example, the bonding particles can include glass (e.g., scaled glass), silver, or other metal particles. For example, the bonding particles can have a melting point and / or sintering temperature below 250°C. For example, this temperature may be much lower than the melting point of silver (961.8°C). As the particle diameter decreases, the melting point and / or sintering temperature may decrease significantly.

[0060] In this example, the outer tube 105 may include glass and may be sealed by local fusion bonding, such as laser, heat press, arc-discharge weld, or other welding or sealing methods. For example, the outer tube 105 may be sealed by frit bonding, glass-compatible soldering or welding, or by using epoxy resin and then hermetic sealing the epoxy resin.

[0061] An inner tube (e.g., first inner tube 130, second inner tube 140, inner tube 230, inner tube 490, etc.) can have a variable porosity along its length. Figure 5 shows an example of a tube-in-tube heat pipe 500, in which an inner tube has different porous regions: a non-porous region 405, a nanopore region 425 (nanometer-sized pores: e.g., 100 nm, 250 nm, 500 nm, 750 nm, etc.), and a micropore region 435 (micron-sized pores: e.g., 1 micron, 10 micron, 25 micron, 50 micron, 100 micron, etc.). For example, the nanopore region 425 and / or the micropore region 435 can be processed to create pores within the inner tube.

[0062] This can include any number of regions with varying degrees of porosity. For example, in use, a tube-in-tube heat pipe 500 can be arranged such that the micropore region 435 acts as a condenser and is placed near a cold region 455, while the nanopore region 425 acts as an evaporator and is placed near a heat source 450. Regions without evaporation or condensation can be non-porous regions 405 of the inner tube. As another example, the micropore region 435 can be an evaporator, while the remaining regions can include a non-porous region 405. Yet another example is that the nanopore region 425 can be an evaporator, while the remainder of the inner tube can be a non-porous region 405.

[0063] As another example, copper microparticles or copper nanoparticles can be bonded (e.g., by sintering) to a copper mesh (e.g., as part of an inner tube), such as a copper mesh comprising a two-layer mesh, the two layers including a fine mesh 351 and a coarse mesh 352. For example, these copper microparticles or copper nanoparticles can be used to bond the copper mesh to an outer tube.

[0064] As another example, glass microparticles or glass nanoparticles can be bonded to a glass mesh, such as a glass mesh (e.g., as part of an inner tube), which comprises a two-layer mesh, including a fine mesh 351 and a coarse mesh 352. These glass microparticles or glass nanoparticles can, for example, be used to bond the glass mesh to an outer tube.

[0065] Figure 6 shows a cross-sectional view of a tube-in-tube heat pipe 600. One or both of the first inner tube 130 and / or the second inner tube 140 may include a woven mesh 605. A single tube-in-tube heat pipe can be shorter than the length of a two-dimensional structure. For example, the space 610 between the heat pipes can be filled with a polymer, glass fiber, metal, etc., which can improve thermal conductivity.

[0066] Figure 7A is an end view of a planar tube-in-tube heat pipe 700, and Figure 7B is a top view of a planar tube-in-tube heat pipe 700, wherein the heat pipe has a plurality of inner tubes 730. In this example, a top shell 720 and a bottom shell 710 can be planar layers that are sealed together around the perimeter of the shell 705. A plurality of inner tubes 730 having an internal volume 731 can be configured within the two shells. In this example, the width of the planar tube-in-tube heat pipe 700 (e.g., 1 cm, 3 cm, 5 cm, etc.) is much greater than its thickness (e.g., 0.075 mm, 0.1 mm, 0.2 mm, 0.5 mm, etc.).

[0067] The inner chamber 715 can contain any fluid, such as water, organic solvents, acetone, any ketone, methanol, any alcohol, pentane, other hydrocarbons, etc.

[0068] Each of the plurality of inner tubes 730 may be a first inner tube 130 or any component including a first inner tube 130 described herein. Each of the plurality of inner tubes 730 may include an internal volume 731.

[0069] The plurality of inner tubes 730 can be coupled to a wick manifold 750 disposed between the bottom housing 710 and the top housing 720. For example, the wick manifold 750 can be coupled to one end of each of the plurality of inner tubes 730. For example, the wick manifold 750 may include a mesh, a sintered particle wick, or micropillars, etc. The wick manifold 750 can be placed near a cooling zone of an electronic device.

[0070] For example, the core manifold 750 may include a hollow region that can be coupled to the internal volume 731 of each of the plurality of inner tubes 730, allowing liquid to flow from the internal volume 731 into the hollow region of the core manifold 750, and vice versa. As another example, the internal volume 731 of each of the plurality of inner tubes 730 may be isolated from a hollow region of the manifold. For example, liquid can flow from the internal volume 731 through the porous wall of the inner tube 730 into the hollow region of the core manifold.

[0071] Figure 8 is a top view of a planar tube-in-tube heat pipe 800, including a plurality of inner tubes 815, each having an internal volume. The plurality of inner tubes 815 may include any of the features of a first inner tube 130, a second inner tube 140, an inner tube 230, and / or an inner tube 490, etc. Each of the plurality of inner tubes 815 has a first end that may converge at a heat source 805, and a second end that may be coupled to a manifold 750 as described above in Figure 7B. The manifold 750 may be curved or bent to carry liquid from the manifold 750 to the heat source 805.

[0072] For example, the internal chamber 715 may contain any fluid, such as water, organic solvents, acetone, any ketones, methanol, any alcohols, pentane, other hydrocarbons, etc.

[0073] Figure 9 is a schematic diagram of a tube-in-tube heat pipe 900 having an inner tube 930 with microwires 920. The inner tube 930 may contact an outer tube 905. In this example, vapor may be located within the internal volume 915 of the inner tube 930, and liquid may be located within the internal volume 910 of the outer tube 905. For example, the outer tube 905 may include an electrical conductor. For example, the inner tube 930 may include a material with low thermal conductivity, such as glass or ceramic. The inner tube 930 may include any or all portions of the first inner tube 130 described herein.

[0074] For example, the microwire 920 may be electroplated and / or may extend into the inner tube 930. The microwire 920 may include copper or other metal and be disposed within the pores of the inner tube 930. The microwire 920 may form a heat dissipation channel between the outer tube 905 and the inner tube 930, allowing heat to be transferred from the outer tube 905 into the inner tube 930. For example, the microwire 920 may also extend into the outer tube 905.

[0075] A planar vapor chamber may include a core tube having a first array of inner tubes and a second array of inner tubes. For example, the first array may include a plurality of inner tubes arranged substantially parallel to each other. For example, the second array may include a plurality of porous tubes perpendicular to the first array. Each inner tube of the first array may include any of the inner tubes disclosed herein (e.g., first inner tube 130). In this example, liquid can be transferred from one inner tube to any of the other inner tubes.

[0076] Any tube-in-tube heat pipe described in this document may have one or more bends to improve flexibility by converting flexing action into torsional action. Figure 10A shows a portion of a heat pipe 1005 with a bend 1010 in a compressed state, and Figure 10B shows a portion of a heat pipe 1005 with a bend 1010 in an extended state. This tube-in-tube heat pipe may be bent at one or more locations to form a laterally expandable or compressible heat pipe, forming the shape of a planar spring.

[0077] Unless otherwise stated, "substantially" means within 5% or 10% of the value mentioned, or within manufacturing tolerances. Unless otherwise stated, "about" means within 5% or 10% of the value mentioned, or within manufacturing tolerances.

[0078] The conjunction "or" is inclusive.

[0079] Terms such as "first," "second," and "third" are used to distinguish individual elements, not to indicate a specific order of these elements, unless otherwise stated or the order is explicitly described or required.

[0080] To provide a thorough understanding of the claimed subject matter, numerous specific details have been listed. However, those skilled in the art will understand that the claimed subject matter can be implemented without these specific details. In other instances, a method, apparatus, or system known to those skilled in the art has not been described in detail so as not to obscure the claimed subject matter.

[0081] Although the subject matter of this case has been described in detail with specific embodiments, those skilled in the art can easily modify and change these examples to equivalents after understanding the above content. Therefore, the content disclosed in this case is presented for illustrative purposes and not for limitation, and such modifications, changes and / or additions to the subject matter of this case are not excluded, as these are obvious to those skilled in the art.

[0082] 100: Tube-in-tube heat pipe

[0083] 105: External Management

[0084] 110: Polymer coating layer

[0085] 115: Internal volume

[0086] 120: First end

[0087] 121: Second End

[0088] 125: Passivation layer

[0089] 130: First Inner Tube

[0090] 131: First internal volume

[0091] 140: Second inner tube

[0092] 141: Second internal volume

[0093] 200: Tube-in-tube heat pipe

[0094] 230: Inner tube

[0095] 231: Internal volume

[0096] 240: Space

[0097] 300: Tube-in-tube heat pipe

[0098] 305: External Pipe

[0099] 351:Fine mesh

[0100] 352:Coarse mesh

[0101] 354: Steam passage

[0102] 361: Fine thread

[0103] 362: Coarse thread

[0104] 366: Fine wire

[0105] 367: Thick wire

[0106] 371: Opening

[0107] 372: Opening

[0108] 381: Gap

[0109] 400: Layered mesh heat pipe

[0110] 405: Non-porous area

[0111] 425: Nanopore region

[0112] 435: Micrometer pore region

[0113] 450: Heat source

[0114] 455: Cold Zone

[0115] 480: External clearance

[0116] 482: Internal clearance

[0117] 490: Inner tube

[0118] 500: Tube-in-tube heat pipe

[0119] 600: Tube-in-tube heat pipe

[0120] 605: Woven Mesh

[0121] 610: Space

[0122] 700: Tube-in-tube heat pipe

[0123] 705: Outer casing

[0124] 710: Bottom casing

[0125] 715: Internal chamber

[0126] 720: Top Shell

[0127] 730: Internal tube

[0128] 731: Internal volume

[0129] 750: Core Manifold

[0130] 800: Tube-in-tube heat pipe

[0131] 805: Heat source

[0132] 815: Inner tube

[0133] 900: Tube-in-tube heat pipe

[0134] 905: Foreign Management

[0135] 910: Internal volume

[0136] 915: Internal volume

[0137] 920: Microwire

[0138] 930: Internal tube

[0139] 1005: Heat pipe

[0140] 1010: Curved

[0141] AA: Section

[0142] BB: Section

Claims

1. A tube-in-tube heat pipe, comprising: An outer tube having a cylindrical shape extending from a first end to a second end; And at least one inner tube disposed within the outer tube, and also having a cylindrical shape extending from a first end to a second end; wherein the inner tube comprises a double-layer porous structure consisting of a porous outer layer and a porous inner layer, and the porous outer layer and the porous inner layer have an average gap greater than or equal to 0.08 mm; wherein the first end and the second end are closed, such that a first chamber is formed inside the inner tube, and a second chamber is formed between the outer tube and the porous outer layer; wherein the first chamber is filled with a liquid, and the outer surface of the outer tube has a first region and a second region, the first region being for contact with a heat source, and The second region is used for heat release; the first region and the second region are spaced apart from each other in the axial direction of the outer tube; when the heat source releases heat to the first region, the liquid is heated to form vapor and enters the second chamber, and then moves in the second chamber according to the difference in saturation pressure; during the movement in the second chamber, the vapor cannot flow back to the first chamber due to the capillary pressure formed by the double-layer porous structure and the liquid phase saturation pressure difference between the outer tube and the double-layer porous structure; when it moves to a cold region in the second chamber, the vapor condenses into droplets and seeps back into the first chamber.

2. A tube-in-tube heat pipe as described in claim 1, wherein, The outer tube is made of porous inorganic material, and the porous outer layer and the porous inner layer are also made of porous inorganic material.

3. A tube-in-tube heat pipe as described in claim 2, wherein, The porous inorganic material includes porous glass, porous copper, or porous ceramics.

4. A tube-in-tube heat pipe as described in claim 1, wherein, Either or both of the porous outer layer and the porous inner layer are coated with an inorganic material.

5. A tube-in-tube heat pipe as described in claim 1, wherein, The porous outer layer encloses the porous inner layer, and there is an average gap width of less than or equal to 0.08 mm between the porous outer layer and an outer surface of the porous inner layer.

6. A tube-in-tube heat pipe as described in claim 1, wherein, The porous outer layer includes a plurality of first wires, and the porous inner layer includes a plurality of second wires; wherein the cross-sectional dimension of the first wires is half the cross-sectional dimension of the second wires.

7. A tube-in-tube heat pipe as described in claim 1, wherein, The porous outer layer and the porous inner layer, or both, include a portion having microparticles or nanoparticles.

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