Graded pressure-equalizing type collaborative heat transfer structure of multiple heat pipe bundles and balancing method

Abstract

The embodiment of the invention provides a collaborative heat transfer structure and balancing method of a graded pressure-equalizing type multi-heat-pipe bundle, and relates to the technical field of high-heat-flux heat energy transmission. The problems that in a non-uniform thermal field, a multi-heat-pipe parallel beam is prone to causing steam blocking backflow and liquid-phase working medium cutoff due to local steam high pressure are solved. A transverse migration channel is provided for steam through a porous material of an integrated steam distribution cavity and a three-dimensional through hole channel, a conical diffusion micropore gradient expansion design is adopted, local high-pressure steam can be conveniently collected due to a small inlet, and steam diffusion can be accelerated due to a large outlet. According to the Darcy law and the Knudsen diffusion effect, permeation flow and molecular diffusion flow can be excited, steam diffusion is accelerated, rapid transverse migration is achieved, dynamic balance of steam pressure in a condensation area is achieved within the sub-second time, and the overall heat transfer efficiency and stability of a heat pipe bundle are improved.

Description

Technical Field

[0001] This invention relates to the field of high heat flux density heat transfer technology, and more specifically, to a graded pressure equalization type multi-heat tube bundle cooperative heat transfer structure and balancing method. Background Technology

[0002] A heat pipe is a sealed vacuum tube filled with a working fluid and a capillary structure, achieving efficient heat transfer through a working fluid evaporation-condensation cycle. While multi-heat pipe bundle designs can increase the heat transfer area by 5-20 times compared to a single pipe, they have fundamental drawbacks in real-world non-uniform thermal fields. When a localized area of ​​the heat pipe bundle experiences high heat flux (>300 W / cm²), the vapor velocity in that area increases dramatically (reaching 15-30 m / s). This vapor flow creates a localized high-pressure zone at the condensation section outlet, inhibiting the backflow of condensate from adjacent low-temperature areas, resulting in a vicious cycle of "vapor blockage-liquid phase interruption" between heat pipes.

[0003] Existing solutions employ a passive balancing method by increasing the volume of the condensing chamber, which alleviates the pressure difference in a small area but sacrifices more than 50% of the effective heat transfer length; or they attempt to add an external pressure equalizing pipe, but this introduces additional heat loss, resulting in an 18% decrease in overall thermal conductivity. Summary of the Invention

[0004] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0005] The objectives of this invention include, for example, providing a graded, pressure-equalizing multi-heat pipe bundle cooperative heat transfer structure and balancing method, which can improve the problem that multi-heat pipe bundles connected in parallel are prone to steam blockage and backflow and liquid working fluid interruption due to local high steam pressure in non-uniform thermal fields.

[0006] The embodiments of the present invention can be implemented as follows: An embodiment of the present invention provides a graded pressure equalization type multi-heat pipe bundle synergistic heat transfer structure, including an integrated steam distribution chamber and multiple parallel heat pipes, wherein the heat pipes include an evaporation section and a condensation section; the integrated steam distribution chamber is disposed inside the condensation section of the heat pipes, the integrated steam distribution chamber is made of a porous material and has a three-dimensional through-hole structure formed inside, the cavity wall of the integrated steam distribution chamber is densely covered with conical diffusion micropores that penetrate along the steam flow direction, and the conical diffusion micropores expand in a gradient along the steam flow direction, such that the diameter of the steam inlet end is smaller than the diameter of the steam outlet end.

[0007] In addition, the graded pressure equalization type multi-heat tube bundle cooperative heat transfer structure provided in the embodiments of the present invention may also have the following additional technical features: Optionally, the porosity of the pore structure of the integrated steam distribution chamber is 55%-68%.

[0008] Optionally, the porosity of the pore structure of the integrated steam distribution chamber is 62±3%.

[0009] Optionally, the diameter of the steam inlet end of the conical diffusion micropore is 0.08-0.12 mm, and the diameter of the steam outlet end is 0.25-0.35 mm.

[0010] Optionally, the diameter of the steam inlet end of the conical diffusion micropore is 0.1 mm, and the diameter of the steam outlet end is 0.3 mm.

[0011] Optionally, the integrated steam distribution chamber is a thin-walled cavity that fits against the inner wall of the condensation section.

[0012] Optionally, the integrated steam distribution chamber is integrally formed from a metal material using additive manufacturing technology.

[0013] Optionally, the metallic material is a titanium alloy.

[0014] Optionally, the inner wall of the evaporation section of the heat pipe is provided with a gradient composite capillary core, which includes a base capillary layer and a reinforcing capillary layer stacked sequentially from the inner wall of the heat pipe outward, wherein the equivalent capillary pore size of the reinforcing capillary layer is smaller than the equivalent capillary pore size of the base capillary layer.

[0015] Optionally, the base capillary layer is a sintered metal powder layer.

[0016] Optionally, the average pore size of the sintered metal powder layer is 45-55 μm.

[0017] Optionally, the enhanced capillary layer is a nanomaterial array layer grown in situ on the surface of the sintered metal powder layer.

[0018] Optionally, the equivalent capillary pore size of the nanomaterial array layer is 1-10 μm.

[0019] Optionally, the nanomaterial array layer is a carbon nanotube array layer.

[0020] Optionally, the carbon nanotube array layer is a multi-walled carbon nanotube array layer.

[0021] Optionally, the carbon nanotube array layer is a vertically grown array layer.

[0022] Embodiments of the present invention also provide a method for synergistic heat transfer balance using a graded, pressure-equalizing multi-heat-tube bundle, implemented using a graded, pressure-equalizing multi-heat-tube bundle synergistic heat transfer structure, comprising: The conical diffusion micropores on the integrated steam distribution chamber collect locally high-pressure steam generated by the non-uniform thermal field. The high-pressure steam is accelerated and diffused by utilizing the gradient expansion structure of the conical diffusion micropores along the steam flow direction, which synergistically stimulates the permeation flow dominated by Darcy's law and the molecular diffusion flow dominated by Knudsen diffusion effect. The accelerated and diffused steam enters the three-dimensional through-hole structure of the integrated steam distribution chamber for rapid lateral migration, thereby achieving dynamic equilibrium of steam pressure in the condensation region of the heat pipe bundle within a sub-second time.

[0023] The beneficial effects of the graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure and balancing method of the present invention include, for example: The synergistic heat transfer structure of the graded, pressure-equalizing multi-heatpipe bundle features gradient conical diffusion micropores with small inlets and large outlets, reducing steam permeation resistance (Darcy's law) and increasing permeability in high-pressure areas, thus accelerating steam extraction. Secondly, the conical diffusion micropores have pore sizes matching the Knudsen diffusion scale, where collisions between steam molecules and pore walls dominate, dramatically increasing the diffusion coefficient and resulting in extremely fast molecular diffusion. These two factors work together to allow steam to migrate rapidly laterally and achieve dynamic pressure equalization within sub-second intervals through a three-dimensional interconnected network of channels. This mitigates the steam blockage effect of localized high pressure on condensate backflow, ensuring synergistic, stable, and efficient heat transfer across multiple heatpipes in non-uniform thermal fields.

[0024] The graded pressure equalization type multi-heat tube bundle cooperative heat transfer balance method, implemented with the above-mentioned heat transfer structure, can improve the problem that multi-heat tube bundles connected in parallel are prone to steam blockage and backflow and liquid working fluid interruption due to local steam high pressure in non-uniform thermal fields. Attached Figure Description

[0025] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0026] Figure 1 A schematic diagram of the graded pressure equalization type multi-heat tube bundle cooperative heat transfer structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of the heat pipes in the graded pressure equalization type multi-heat pipe bundle cooperative heat transfer structure provided in an embodiment of the present invention. Figure 3 for Figure 2 A magnified view of part A in the image.

[0027] Icons: Synergistic heat transfer structure of multi-heat pipe bundle with graded pressure equalization - 10; heat pipe - 11; evaporation section - 100; gradient composite capillary wick - 110; sintered metal powder layer - 111; nanomaterial array layer - 112; insulation section - 200; condensation section - 300; integrated vapor distribution chamber - 310; three-dimensional through-hole structure - 311; conical diffusion micropores - 312. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0029] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," "outer," or "vertical" appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use, and does not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0030] At the same time, it should be noted that the terms "first" and "second" are used only for distinguishing descriptions and should not be interpreted as indicating or implying relative importance.

[0031] The following is combined with Figures 1 to 3 The graded pressure equalization type multi-heat tube bundle cooperative heat transfer structure 10 provided in this embodiment is described in detail.

[0032] Please refer to Figure 1 , Figure 2 and Figure 3 The present invention provides a graded pressure equalization type multi-heat pipe bundle cooperative heat transfer structure 10, including an integrated steam distribution chamber 310 and multiple parallel heat pipes 11. The heat pipes 11 include an evaporation section 100 and a condensation section 300. The integrated steam distribution chamber 310 is disposed inside the condensation section 300 of the heat pipes 11. The integrated steam distribution chamber 310 is made of porous material and has a three-dimensional through-hole structure 311 formed inside. The cavity wall of the integrated steam distribution chamber 310 is densely covered with conical diffusion micropores 312 that penetrate along the steam flow direction. The conical diffusion micropores 312 are gradually enlarged along the steam flow direction, so that the diameter of the steam inlet end is smaller than the diameter of the steam outlet end.

[0033] The heat pipe 11 includes an evaporation section 100, an insulation section 200, and a condensation section 300 connected in sequence. Figure 2 The direction indicated by the middle arrow a2 is the direction from the evaporation of the heat-absorbing medium in the evaporation section 100 to the condensation section 300. Figure 2The direction indicated by the middle arrow a1 is the direction in which the heat-releasing medium in the condensation section 300 condenses and flows back to the evaporation section 100. The "three-dimensional interconnected channel structure 311" refers to the channels extending and distributing in the X, Y, and Z dimensions of space, rather than being limited to a two-dimensional plane or a single direction. The channels are interconnected, forming a continuous, meandering, but dead-end-free maze-like network of paths. Fluid (here, steam) can enter through one path and exit through another path that is not directly adjacent in space. The "steam flow direction" is the local flow direction penetrating the thickness of the integrated steam distribution chamber 310. Figure 3 In the direction indicated by the middle arrow W, after the steam enters the porous material, it needs to penetrate the cavity thickness laterally (radially) to reach the cooling interface. Therefore, the conical diffusion micropores 312 expand in a gradient from the side near the center of the heat pipe 11 towards the wall side.

[0034] The integrated steam distribution chamber 310, located inside the condensation section 300, effectively collects and distributes steam. The three-dimensional through-hole structure 311 provides a lateral migration channel for steam, and the gradient expansion design of the tapered diffusion micropores 312 optimizes steam transmission according to steam flow characteristics, improves the uniformity of steam distribution, and thus enhances the overall heat transfer efficiency of the heat pipe bundle.

[0035] In this embodiment, the porosity of the channel structure 311 of the integrated steam distribution chamber 310 is 55%-68%. Porosity directly determines the permeability and effective diffusion area of ​​the porous medium. The range of 55%-68% ensures high connectivity while maintaining sufficient structural strength. High porosity ensures high flux and low flow resistance for lateral steam migration.

[0036] In this embodiment, the porosity of the channel structure 311 of the integrated steam distribution chamber 310 is 62±3%. 62±3% is a preferred embodiment. Within this specific range, the steam flow and distribution effect is better, the steam pressure can be better balanced, and the heat pipe bundle can maintain relatively stable heat transfer performance under different operating conditions.

[0037] In this embodiment, the diameter of the steam inlet end of the conical diffusion micropore 312 is 0.08-0.12 mm, and the diameter of the steam outlet end is 0.25-0.35 mm.

[0038] This size range can synergistically stimulate Darcy flow and Knudsen diffusion. It increases the ratio of pore size to the mean free path of vapor molecules by hundreds of times, making the Knudsen diffusion effect extremely significant (the diffusion coefficient Dk is greatly increased).

[0039] According to Darcy's law, pressure difference for, ; in, The pressure difference represents the pressure difference generated at both ends when a fluid passes through a porous medium, where μ is the vapor viscosity and V is the vapor velocity. L Let κ be the thickness of the porous medium, κ = 3.2 × 1 ¹² m² represents permeability; the gradient pore size increases the κ value in the high-pressure zone by 42%. Combined with the Knudsen diffusion effect, ; Where Dk is the diffusion coefficient and d is the pore size. R The universal gas constant is a physical constant widely used in thermodynamics and fluid mechanics. T Where is the thermodynamic temperature, and M is the molar mass of a water molecule. A pore size d ≈ 500 times the mean free path λ of the molecules results in a discontinuous flow pattern, causing the collision frequency between steam molecules and the pore walls to be higher than that between molecules. This significantly increases the diffusion coefficient Dk, thereby increasing the lateral movement velocity of the steam.

[0040] In this embodiment, the steam inlet diameter of the conical diffusion micropore 312 is 0.1 mm, and the steam outlet diameter is 0.3 mm. At this size, a good balance is achieved between steam collection and diffusion, enabling more effective steam acceleration and diffusion, and improving the speed and effectiveness of steam pressure equalization in the heat pipe bundle condensation region. According to the Darcy's law and Knudsen diffusion effect formula, the 0.1-0.3 mm pore size increases the diffusion coefficient Dk to 8.3 × 10⁻¹⁰. m² / s, increasing the steam lateral migration speed to 14 times that of traditional designs, with a migration time of <0.3 seconds, completely eliminating local backflow obstruction.

[0041] Reference Figure 2 and Figure 3 In this embodiment, the integrated steam distribution chamber 310 is a thin-walled cavity that fits into the inner wall of the condensing section 300. The thin-walled cavity fits into the inner wall of the condensing section 300, which can ensure a tight connection between the steam distribution chamber and the condensing section 300 of the heat pipe 11, reduce steam leakage, save materials and space, and at the same time, the thin-walled structure has less obstruction to steam flow, which is beneficial to the transmission and distribution of steam.

[0042] Reference Figure 1 In this embodiment, the integrated steam distribution chamber 310 is integrally formed from metal material using additive manufacturing technology. Specifically, the additive manufacturing technology is selective laser melting (SLM).

[0043] Additive manufacturing technology can achieve one-piece molding of complex structures, and can accurately manufacture an integrated steam distribution chamber 310 with a three-dimensional through-hole structure 311 and a conical diffusion micropore 312, ensuring the accuracy and quality of the structure and improving production efficiency. At the same time, the metal material has good thermal conductivity and strength, which can meet the working requirements of heat pipe bundles.

[0044] In this embodiment, the metallic material is titanium alloy. Titanium alloy has advantages such as low density, high strength, and good corrosion resistance. Using titanium alloy to make the integrated steam distribution chamber 310 can not only ensure the strength and stability of the structure under high temperature and high pressure environment, but also reduce the weight of the heat pipe bundle and improve its reliability and service life.

[0045] Reference Figure 2 and Figure 3 In this embodiment, a gradient composite capillary 110 is provided on the inner wall of the evaporation section 100 of the heat pipe 11. The gradient composite capillary 110 includes a base capillary layer and a reinforcing capillary layer stacked sequentially from the inner wall of the heat pipe 11 outward. The equivalent capillary pore size of the reinforcing capillary layer is smaller than that of the base capillary layer.

[0046] The gradient composite capillary wick 110 is designed to utilize the characteristics of capillary layers with different equivalent capillary pore sizes. The base capillary layer provides basic capillary liquid absorption capacity, while the enhanced capillary layer, due to its smaller pore size, generates greater capillary force, which can more effectively draw liquid from the condensation section 300 back to the evaporation section 100, improving the circulation efficiency of the heat pipe 11 and enhancing heat transfer performance.

[0047] Reference Figure 2 and Figure 3 In this embodiment, the basic capillary layer is a sintered metal powder layer 111. The sintered metal powder layer 111 has a porous structure, providing a certain capillary liquid absorption capacity. Furthermore, the metal powder sintering process is mature, allowing control over pore size and distribution, ensuring stable performance of the basic capillary layer. It also bonds well with the inner wall of the heat pipe 11, improving the overall performance of the heat pipe 11. Specifically, the sintered metal powder layer 111 is a copper powder sintered layer.

[0048] In this embodiment, the average pore size of the sintered metal powder layer 111 is 45-55 μm. This average pore size range allows the sintered metal powder layer 111 to maintain sufficient capillary liquid absorption capacity while possessing good permeability, enabling liquid to pass through smoothly. This avoids excessive liquid flow resistance due to excessively small pore size or impaired capillary liquid absorption effect due to excessively large pore size, thereby optimizing the heat transfer performance of the heat pipe 11. Specifically, a pore size of 50±5 μm can improve the liquid absorption effect.

[0049] Reference Figure 2 and Figure 3In this embodiment, the enhanced capillary layer is a nanomaterial array layer 112 grown in situ on the surface of the metal powder sintered layer 111. "In-situ growth" refers to using the metal powder sintered layer 111 as a substrate, directly synthesizing nanomaterials (such as carbon nanotubes) on the substrate surface through specific chemical or physical methods to form an array layer. During the growth process, the nanomaterials and the substrate form stable chemical bonds or strong physical bonds, eliminating the need for subsequent bonding or other additional steps to achieve the connection between the two. The in-situ grown nanomaterial array layer 112 is tightly bonded to the metal powder sintered layer 111, fully utilizing the small size effect and high surface activity of the nanomaterials to generate greater capillary force, further improving the liquid absorption capacity of the heat pipe 11. Simultaneously, the special structure of the nanomaterial array layer 112 also facilitates the uniform distribution and transport of the liquid.

[0050] In this embodiment, the equivalent capillary pore size of the nanomaterial array layer 112 is 1-10 μm. This range of equivalent capillary pore size enables the nanomaterial array layer 112 to generate strong capillary forces, effectively drawing in liquid. Simultaneously, the smaller pore size also limits the liquid flow velocity to a certain extent, allowing the liquid to fully evaporate in the evaporation section 100, thus improving the heat transfer efficiency of the heat pipe 11. Specifically, the equivalent capillary pore size of the nanomaterial array layer 112 is 5 μm, further improving the heat transfer efficiency.

[0051] Reference Figure 1 In this embodiment, the nanomaterial array layer 112 is a carbon nanotube array layer. Carbon nanotubes have a unique electronic structure and excellent physicochemical properties. Their array layer has an extremely high specific surface area and good thermal conductivity, which can generate strong capillary force and quickly transfer heat away, further improving the heat transfer performance and cycle efficiency of the heat pipe 11.

[0052] Reference Figure 1 In this embodiment, the carbon nanotube array layer is a multi-walled carbon nanotube array layer. "Multi-walled" in "multi-walled carbon nanotube array layer" refers to a hollow tubular nanomaterial composed of two or more coaxial cylindrical graphite layers nested together. A multi-walled carbon nanotube array layer refers to a continuous, dense, thin-film functional structure formed on the substrate surface through a specific process, consisting of a large number of multi-walled carbon nanotubes arranged in a highly ordered orientation (e.g., vertical, inclined).

[0053] Multi-walled carbon nanotubes have higher strength and stability. Compared with single-walled carbon nanotubes, the multi-walled carbon nanotube array layer can better maintain its structural integrity under the working environment of heat pipe 11, and continuously exert a strong capillary liquid absorption and heat transfer effect, thereby improving the reliability and service life of heat pipe 11.

[0054] Reference Figure 2 and Figure 3In this embodiment, the carbon nanotube array layer is a vertically grown array layer. "Vertical growth" specifically refers to the fact that the main extension direction or long axis direction of one-dimensional nanomaterials (such as carbon nanotubes, nanowires, and nanorods) on the substrate surface is basically consistent with the normal direction of the substrate surface (usually within ±15°), thus forming a highly oriented, forest-like or brush-like array structure. The vertically grown carbon nanotube array layer enables rapid liquid transport in the vertical direction, reducing the liquid transport path and increasing the liquid absorption rate. Simultaneously, the vertical structure also facilitates vertical heat transfer, enhancing the heat transfer effect of the heat pipe 11 and enabling the heat pipe 11 to respond more quickly to changes in the thermal field.

[0055] Embodiments of the present invention also provide a method for synergistic heat transfer balance of a graded pressure-equalizing multi-heat tube bundle, implemented using a graded pressure-equalizing multi-heat tube bundle synergistic heat transfer structure 10, comprising: Local high-pressure steam generated by the non-uniform thermal field is collected through the conical diffusion micropores 312 on the integrated steam distribution chamber 310; By utilizing the gradient expansion structure of the conical diffusion micropores 312 along the steam flow direction, the permeation flow dominated by Darcy's law and the molecular diffusion flow dominated by Knudsen diffusion effect are synergistically excited to accelerate and diffuse high-pressure steam. The accelerated and diffused steam enters the three-dimensional through-hole structure 311 of the integrated steam distribution chamber 310 for rapid lateral migration, thereby achieving dynamic equilibrium of steam pressure in the condensation region of the heat pipe bundle within a sub-second time.

[0056] The integrated steam distribution chamber 310 collects locally high-pressure steam generated by a non-uniform thermal field through conical diffusion micropores 312. The gradient expansion structure of the conical diffusion micropores 312 stimulates permeation flow and molecular diffusion flow to accelerate and diffuse the high-pressure steam, allowing it to rapidly migrate laterally into the three-dimensional through-hole structure 311, achieving dynamic equilibrium of steam pressure in the condensation region. This effectively solves the problem of uneven steam pressure in the condensation region of the heat pipe bundle under non-uniform thermal fields. Through the special structure and function of the conical diffusion micropores 312, steam diffusion is accelerated, and the three-dimensional through-hole structure 311 enables rapid lateral migration of steam, achieving steam pressure equilibrium within sub-second time, thus improving the heat transfer stability and efficiency of the heat pipe bundle under different thermal field conditions.

[0057] According to the graded pressure equalization type multi-heat tube bundle cooperative heat transfer structure 10 provided in this embodiment, the working principle of the graded pressure equalization type multi-heat tube bundle cooperative heat transfer structure 10 includes: An advanced heat pipe bundle structure that solves the backflow interference failure under the condition of 11 parallel operation of multiple heat pipes through a steam pressure dynamic balance mechanism is suitable for scenarios that require high-power isothermal heat transfer in non-uniform thermal fields, such as solar concentrator heat absorption units, heat dissipation systems of high-power electronic equipment, and passive waste heat removal devices of nuclear reactors.

[0058] An 8mm thick porous titanium alloy cavity is bonded inside the condensation section 300 of the heat pipe bundle, formed using laser selective melting technology to achieve a through-hole structure with a porosity of 62±3% (pore spacing 0.25mm). The inner wall of the cavity contains 12,000 conical diffusion micropores 312, with an inlet pore diameter of 0.10mm and an outlet pore diameter of 0.30mm. The pore size d ≈ 500 times the mean free path λ of the molecules, generating a discontinuous flow state, resulting in a higher frequency of collisions between vapor molecules and the pore walls than between molecules. The 0.1-0.3mm pore size increases the diffusion coefficient Dk to 8.3×1. m² / s, increasing the steam lateral migration speed to 14 times that of traditional designs, with a migration time of <0.3 seconds, completely eliminating local backflow obstruction.

[0059] Secondly, a gradient capillary core structure is adopted, with the evaporation section 100 employing a double-layer composite core. The inner layer is a sintered copper powder core, with 99.97% pure spherical copper powder having a particle size of 50μm. Through sintering, a capillary network with a pore size of 50±5μm is formed, achieving high-speed liquid absorption. A multi-walled carbon nanotube array is vertically grown on the surface of the copper powder. The nanotubes have a diameter of 10nm and a length of 50μm, and the spacing between the tubes forms a submicron channel with an equivalent pore size of 5μm, enhancing the capillary limit and improving antigravity performance. The inner layer of copper powder generates a basic capillary force of 5.28kPa, achieving high-speed liquid absorption of 0.28m / s; the outer nanotube array, through the submicron channel, enhances the capillary force to 10.56kPa, causing the antigravity coefficient to jump from 1.47 in the single-layer structure to 1.91.

[0060] The capillary structure is a porous material layer on the inner wall of heat pipe 11, which drives the condensate back to the evaporation section 100 through capillary force. Traditional parallel heat pipe bundles lack a vapor chamber pressure balancing mechanism, resulting in excessively high vapor velocity in the high-temperature region of heat pipe 11, hindering the condensate return in the low-temperature region and causing a deterioration in the overall isothermal performance of the heat pipe bundle (temperature difference > 15℃). The root cause lies in the lack of dynamic pressure self-regulation in the vapor flow channel design. This problem is caused by thermodynamic imbalance, lag in the passive pressure equalization chamber response, and material thermal expansion mismatch. Thermodynamic imbalance refers to the fact that as the vapor velocity increases, the vapor inertial force counteracts the capillary force driving effect, causing the capillary limit to decrease in an inverse square proportion. Lag in the passive pressure equalization chamber response refers to a volume compensation coefficient γ ≥ 2.5 resulting in a thermal response delay > 60 seconds, which cannot match rapid heating conditions. Material thermal expansion mismatch refers to the difference in expansion coefficients between copper and stainless steel at 300℃, leading to a cracking rate of > 35% in the sintered copper layer.

[0061] The graded pressure equalization type multi-heat tube bundle cooperative heat transfer structure 10 provided in this embodiment has at least the following advantages: Dynamic pressure coupling of the heat pipe bundle is achieved through a porous integrated steam distribution chamber 310, fundamentally solving the steam backflow interference problem. The gradient design of the conical diffusion micropores 312 reduces flow resistance and increases permeability by increasing the outlet orifice diameter, diverting steam from the high-pressure zone to the low-pressure zone and reducing steam pressure non-uniformity. Furthermore, the pore size of the conical diffusion micropores 312 (0.1-0.3 mm) significantly increases the Knudsen diffusion coefficient, accelerating lateral steam migration and reducing diffusion time.

[0062] The gradient composite capillary wick 110, through the functional division and synergy of the large-pore high-speed transport layer and the submicron high capillary force layer, provides an ultra-high capillary force of 10.56 kPa while ensuring high-speed reflux. The anti-gravity coefficient jumps from 1.47 to 1.91, ensuring absolutely reliable reflux of the liquid phase after pressure equalization.

[0063] The steam distribution chamber quickly eliminates pressure unevenness, creating a stable working environment for the capillary wick; the enhanced capillary wick provides sufficient reflux protection, and the two form a positive feedback, enabling the entire heat pipe bundle to maintain excellent isothermal properties and heat transfer reliability even under extremely non-uniform thermal fields.

[0064] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A graded, pressure-equalizing, multi-heat tube bundle synergistic heat transfer structure, characterized in that, include: An integrated steam distribution chamber and multiple parallel heat pipes are provided. The heat pipes include an evaporation section and a condensation section. The integrated steam distribution chamber is located inside the condensation section of the heat pipes. The integrated steam distribution chamber is made of a porous material and has a three-dimensional through-hole structure inside. The chamber wall of the integrated steam distribution chamber is densely covered with conical diffusion micropores that penetrate along the steam flow direction. The conical diffusion micropores expand in a gradient along the steam flow direction, so that the diameter of the steam inlet end is smaller than the diameter of the steam outlet end.

2. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 1, characterized in that, The porosity of the pore structure of the integrated steam distribution chamber is 55%-68%.

3. The graded pressure-equalizing multi-heat tube bundle synergistic heat transfer structure according to claim 2, characterized in that, The porosity of the pore structure of the integrated steam distribution chamber is 62±3%.

4. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 1, characterized in that, The diameter of the steam inlet end of the conical diffusion micropore is 0.08-0.12 mm, and the diameter of the steam outlet end is 0.25-0.35 mm.

5. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 4, characterized in that, The diameter of the steam inlet end of the conical diffusion micropore is 0.1 mm, and the diameter of the steam outlet end is 0.3 mm.

6. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 1, characterized in that, The integrated steam distribution chamber is a thin-walled cavity that fits into the inner wall of the condensation section.

7. The graded pressure-equalizing multi-heat tube bundle synergistic heat transfer structure according to claim 6, characterized in that, The integrated steam distribution chamber is integrally formed from metal material using additive manufacturing technology.

8. The graded pressure-equalizing multi-heat tube bundle synergistic heat transfer structure according to claim 7, characterized in that, The metallic material is a titanium alloy.

9. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to any one of claims 1-8, characterized in that, The inner wall of the evaporation section of the heat pipe is provided with a gradient composite capillary core, which includes a base capillary layer and a reinforcing capillary layer stacked sequentially from the inner wall of the heat pipe outward. The equivalent capillary pore size of the reinforcing capillary layer is smaller than that of the base capillary layer.

10. The graded pressure-equalizing multi-heat tube bundle synergistic heat transfer structure according to claim 9, characterized in that, The basic capillary layer is a sintered metal powder layer.

11. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 10, characterized in that, The average pore size of the sintered metal powder layer is 45-55 μm.

12. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 10, characterized in that, The enhanced capillary layer is an array of nanomaterials grown in situ on the surface of the sintered metal powder layer.

13. The graded pressure-equalizing multi-heat tube bundle synergistic heat transfer structure according to claim 12, characterized in that, The equivalent capillary pore size of the nanomaterial array layer is 1-10 μm.

14. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 12, characterized in that, The nanomaterial array layer is a carbon nanotube array layer.

15. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 14, characterized in that, The carbon nanotube array layer is a multi-walled carbon nanotube array layer.

16. The graded pressure-equalizing multi-heat tube bundle cooperative heat transfer structure according to claim 14 or 15, characterized in that, The carbon nanotube array layer is a vertically grown array layer.

17. A method for coordinated heat transfer balance of a multi-heat tube bundle with graded pressure equalization, characterized in that, The implementation using the graded pressure-equalizing multi-heat tube bundle synergistic heat transfer structure according to any one of claims 1-16 includes: The conical diffusion micropores on the integrated steam distribution chamber collect locally high-pressure steam generated by the non-uniform thermal field. The high-pressure steam is accelerated and diffused by utilizing the gradient expansion structure of the conical diffusion micropores along the steam flow direction, which synergistically stimulates the permeation flow dominated by Darcy's law and the molecular diffusion flow dominated by Knudsen diffusion effect. The accelerated and diffused steam enters the three-dimensional through-hole structure of the integrated steam distribution chamber for rapid lateral migration, thereby achieving dynamic equilibrium of steam pressure in the condensation region of the heat pipe bundle within a sub-second time.

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