High-temperature heat pipe for double heat conduction

Abstract

The invention relates to a double-heat-conduction high-temperature heat pipe which is provided with a composite capillary core formed by weaving low-heat-conduction coating stainless steel wires and conventional stainless steel wires so as to form evaporation areas and liquid supplementing areas which are distributed alternately. Wherein the evaporation area is a conventional stainless steel wire mesh, and the liquid supplementing area is a stainless steel wire mesh coated with a low-heat-conduction ceramic coating. Through composite weaving of the low-heat-conduction coating silk screen and the conventional silk screen, the evaporation function and the liquid supplementing function are separated from the source, the problem of heat pipe failure caused by the capillary limit and the boiling limit is solved, and physical separation of the evaporation function and the liquid supplementing function is achieved. According to the scheme, through material innovation (boron nitride-yttrium oxide coating) and structure optimization (alternate weaving of pores), the capillary limit and the boiling limit are remarkably improved, meanwhile, the heat pipe is endowed with local failure redundancy capacity, and a high-reliability heat management solution is provided for high-temperature application (such as nuclear reactors and spacecrafts).

Description

Technical Field

[0001] The present invention belongs to the technical field of high-temperature two-phase heat transfer device design and thermal management, specifically a high-temperature heat pipe for dual thermal conductivity. The high-temperature heat pipe is based on a dual thermal conductivity capillary wick structure and is particularly suitable for efficient heat transfer and dry-out suppression of alkali metal (such as sodium and potassium) working fluids at extreme temperatures (>800°C). Background Art

[0002] High-Temperature Heat Pipes (HTHPs) are passive devices that rely on phase change cycles of a working fluid to achieve efficient heat transfer. They are widely used in scenarios requiring long-term stable operation at extreme temperatures (>800°C). Examples include: nuclear energy: waste heat removal from nuclear reactor cores and heat exchange in molten salt reactors; aerospace: rocket engine nozzle cooling and thermal protection for hypersonic vehicles; and industrial: waste heat recovery from high-temperature smelting furnaces and thermal management in semiconductor manufacturing.

[0003] However, as application scenarios place increasingly stringent demands on heat transfer power density and temperature uniformity, high-temperature heat pipes face the following heat transfer limitations: 1. Heat transfer limit of high temperature heat pipe: (1) Critical Heat Flux (CHF): Bottleneck mechanism: When the evaporation rate of the working fluid (such as liquid sodium or potassium) at the evaporation end exceeds the liquid replenishment capacity of the capillary wick, local areas dry out, resulting in a sharp drop in heat transfer performance, making it difficult to meet the needs of high-power equipment.

[0004] (2) Temperature uniformity limitation: The root cause of the problem: The thermal conductivity of the homogeneous capillary wick is fixed, resulting in uneven heat distribution at the evaporation end, forming a "hot spot" in the local area (temperature fluctuations can reach 80-100°C); the consequence: thermal stress concentration accelerates material fatigue and shortens the life of the heat pipe (for example, the design life of a nuclear reactor heat pipe must be >10 years).

[0005] (3) Compatibility and stability of high-temperature materials: Material degradation: At high temperatures (>800°C), the capillary wick material (such as metal, ceramic) and the liquid metal working fluid are prone to chemical reactions (such as the formation of brittle intermetallic compounds), resulting in pore closure or structural failure; Capillary force attenuation: During long-term high-temperature operation, the pore size and porosity of the porous structure change (such as sintering and densification of the ceramic coating), the capillary force decreases by >30%, and the fluid replenishment capacity deteriorates.

[0006] 2. Improvement directions and limitations of existing technologies: Homogeneous wick optimization: The principle is to use a single material (such as wire mesh or sintered metal) to manufacture the wick, relying on uniform pores to transport the working fluid. Advantages include simple structure and low cost. Disadvantages include fixed thermal conductivity, prone to local overheating at the evaporation end, low heat transfer limit, inability to dynamically adjust the working fluid reflow rate, and high risk of dry-out. Capillary forces can be enhanced by adjusting porosity (such as with sintered metal fibers) or surface wettability (such as with nanocoatings), but the uneven heat flow distribution caused by a single thermal conductivity characteristic remains unresolved.

[0007] Composite wick design: The principle is to combine different materials (such as metal + ceramic) to balance thermal conductivity and capillary force. The advantage is a slight improvement in the heat transfer limit. However, the disadvantage is the difference in thermal expansion coefficients between the different materials, which can lead to delamination and cracking at high temperatures. The metal area has good thermal conductivity but weak capillary force, while the ceramic area has the opposite, limiting overall performance. In other words, combining different materials (such as metal mesh + ceramic particles) to try to balance thermal conductivity and capillary force, but thermal stress at the interface of the heterogeneous materials at high temperatures can easily lead to structural delamination and failure.

[0008] Gradient structures: The principle is to design a pore gradient along the length of the heat pipe (small pore diameter at the evaporation end, large pore diameter at the condensation end). The advantage is more uniform distribution of the working fluid and reduced temperature differences. However, the disadvantage is that a fixed gradient cannot adapt to dynamic changes in heat load, the manufacturing process is complex, and the yield rate is low. In other words, designing a pore gradient along the axial or radial direction of the heat pipe can optimize the working fluid flow path, but it cannot dynamically respond to sudden changes in local heat load (such as power fluctuations in a nuclear reactor).

[0009] Surface wettability coating: The principle is to coat the surface of the capillary wick with nanomaterials (such as ceramic coatings) to enhance the wettability of the working fluid. The advantage is that the short-term capillary force is improved by ~20%. The disadvantage is that the coating is prone to fall off or densification at high temperatures, the performance decays rapidly, and it is easy to chemically react with the liquid metal working fluid.

[0010] In summary, the defects of the existing technology are as follows: (1) Static structural design leads to imbalance between heat flow and fluid replenishment: that is, existing capillary wicks (homogeneous, composite or gradient structures) are all fixed static designs, which cannot dynamically adjust the working fluid supply according to the changes in the heat load at the evaporation end. As a result, the evaporation rate of the working fluid in the high heat flux area exceeds the fluid replenishment capacity, causing local drying up and the working fluid to be retained in the low heat flux area, which reduces the overall heat transfer efficiency and limits the heat transfer limit (CHF). This makes it impossible to meet the high heat flux density heat transport requirements of nuclear reactors, spacecraft and other scenarios.

[0011] (2) The contradiction in material properties is difficult to optimize in a coordinated manner: that is, high thermal conductivity materials (such as metals) and high capillary force materials (such as ceramics) have mutually exclusive properties. The existing composite structure cannot take into account the advantages of both. As a result, the metal area has good thermal conductivity but weak capillary force, resulting in delayed fluid replenishment, and the ceramic area has strong capillary force but poor thermal conductivity, forming local thermal resistance. As a result, the actual heat transfer performance of the composite capillary wick is limited by the "short board effect", and the risk of interface stratification is high at high temperatures.

[0012] (3) Insufficient high temperature stability leads to short life: that is, the existing coating or capillary wick material undergoes structural degradation or interface reaction when operated at >800℃ for a long time, causing the surface coating to High-temperature sintering densification and capillary force attenuation of >40% result in heat pipe life generally being <5 years, far below the nuclear energy / aerospace field requirement of >20 years.

[0013] (4) Lack of dynamic response capability: Existing technologies rely on “fixed pore or gradient design” and are unable to respond to thermal load fluctuations or local heat flux mutations in real time. This causes a sudden increase in heat flux density at the evaporation end of the heat pipe when the nuclear reactor power changes transiently, insufficient fluid replenishment in the static structure, and the inability to quickly suppress local overheating during the cooling of high heat flux electronic devices. This makes the heat pipe prone to instantaneous drying or thermal runaway in dynamic scenarios, significantly reducing reliability.

[0014] (5) High manufacturing cost and complex process: Gradient pores or composite capillary cores require "precision processing technology" (such as gradient sintering and coating deposition), which leads to high cost and low yield rate. The yield rate of gradient sintering process is less than 60%, and nano-coating requires vacuum coating equipment. The manufacturing cost of a single heat pipe increases by >200%, making it difficult to apply it on a large scale in cost-sensitive fields such as industrial waste heat recovery.

[0015] 3.Technology requirements and market trends: Extreme environment requirements: Scenarios such as fourth-generation nuclear reactors and deep space exploration spacecraft require heat pipes to achieve a CHF > 400 W / cm² at >1000°C and a lifespan >20 years. Industrial energy-saving needs: The steel, chemical, and other industries require waste heat recovery devices to operate stably in high-temperature (800-1200°C) corrosive environments. The lifespan of existing heat pipes is generally less than 3 years. Technology upgrade direction: Breaking through the traditional homogeneous capillary wick design and developing a new structure that combines dynamic heat flow control, high capillary force maintenance, and high-temperature material stability has become an urgent industry demand.

[0016] In summary, current high-temperature heat pipe technology is limited by the heat transfer limitations of homogeneous capillary wicks, making it difficult to meet the high power density, high temperature uniformity, and long life requirements in extreme scenarios. Material and structural innovations are urgently needed to achieve active control of heat flux distribution at the evaporation end and a dynamic balance between the working fluid replenishment rate, thereby breaking through the CHF bottleneck and improving reliability.

[0017] Therefore, the present invention proposes improvements to the following key defects of existing high-temperature heat pipes caused by the unseparation of evaporation and liquid replenishment paths: 1. Premature capillary limit triggering: In a homogeneous stainless steel wire mesh capillary wick, all areas participate in both evaporation and recirculation of the working fluid simultaneously. When the heat load increases, the capillary force cannot meet the recirculation requirements (capillary limit), causing the evaporation end to dry out and fail.

[0018] 2. Boiling limit causes structural damage: Under high heat flow, the evaporation end is locally overheated, and the working fluid boils violently (boiling limit), generating bubbles that block pores and accelerate the erosion or deformation of the capillary wick.

[0019] 3. Single failure mode: Once the existing design reaches the capillary or boiling limit, the overall performance of the heat pipe will drop sharply or even fail completely, and there is a lack of a "local failure redundancy" mechanism. Summary of the Invention

[0020] To solve the above problems, the present invention proposes a dual-heat-conducting high-temperature heat pipe, which uses a composite woven structure of low-thermal-conductivity coated wire mesh and conventional wire mesh. The present invention aims to achieve the following goals: 1. Breaking through capillary limits: A low-thermal-conductivity coating suppresses the evaporation activity of parts of the screen, creating independent refill channels. Even if capillary limits are reached in certain areas, the unevaporated screens can still maintain fluid reflux, delaying overall dry-out.

[0021] 2. Improve the boiling limit threshold: The coated wire mesh reduces the conduction of heat to the non-evaporating area, reduces the local temperature rise rate, and avoids pore blockage caused by violent boiling of the working fluid.

[0022] 3. Achieve failure zoning control: By separating the partial evaporation and partial rehydration functions, when the local limit is reached, the non-failed area can still maintain the basic operation of the heat pipe, thereby improving system reliability.

[0023] The present invention proposes a dual-heat-conducting high-temperature heat pipe having a composite capillary wick braided from low-thermal-conductivity-coated stainless steel wire and conventional stainless steel wire to form alternatingly distributed evaporation zones and liquid replenishment zones; Among them, the evaporation area is a conventional stainless steel wire mesh, and the liquid replenishment area is a stainless steel wire mesh coated with a low thermal conductivity ceramic coating.

[0024] Furthermore, the composite woven structure adopts a plain weave process, and the stainless steel wire mesh coated with a low thermal conductivity ceramic coating and the conventional stainless steel wire mesh are alternately arranged in a ratio of 1:1 to 1:5.

[0025] Furthermore, the gaps of the conventional stainless steel wire mesh are 50-80 μm, and the gaps of the stainless steel wire mesh coated with the low thermal conductivity ceramic coating are 30-50 μm.

[0026] Furthermore, the stainless steel wire mesh coated with the low thermal conductivity ceramic coating and the conventional stainless steel wire mesh are alternately arranged in a ratio of 1:3.

[0027] Furthermore, the low thermal conductivity ceramic coating is boron nitride (BN)-yttrium oxide Composite ceramic coating, which achieves high bonding strength and thermal isolation effect through plasma spraying process; Among them, the bottom layer of the low thermal conductivity ceramic coating is a NiCrAlY alloy transition layer, the middle layer is a boron nitride (BN) layer, and the surface layer is yttrium oxide. layer.

[0028] Furthermore, a NiCrAlY transition layer is combined with a laser remelting process to improve the interface bonding strength between the coating and the substrate.

[0029] Furthermore, the thickness of the NiCrAlY alloy transition layer is 5 μm, the thickness of the boron nitride (BN) layer is 10 μm, and the thickness of the yttrium oxide layer is 10 μm. Layer thickness 5 μm.

[0030] Furthermore, the thermal conductivity of the low thermal conductivity coated stainless steel wire is <0.5W / (m•K), and the thermal conductivity of the conventional stainless steel wire is >10W / (m•K).

[0031] Furthermore, the thermal conductivity of the low thermal conductivity coated stainless steel wire is <0.5W / (m•K), and the thermal conductivity of the conventional stainless steel wire is >15W / (m•K).

[0032] Compared with the prior art, the advantages of the present invention are: 1. The composite braided capillary wick structure alternates low-thermal-conductivity coated stainless steel wire (thermal conductivity <0.5 W / (m•K)) with conventional stainless steel wire (thermal conductivity >15 W / (m•K)) in a specific ratio, creating a physical separation between the evaporation zone (conventional wire) and the refill zone (coated wire). The evaporation zone has pores with a diameter of 50-80 μm, ensuring efficient evaporation of the working fluid; the refill zone has pores with a diameter of 30-50 μm, prioritizing the transport of liquid working fluid through capillary forces. This maintains >60% refill capacity even at the capillary limit, increasing the critical heat flux (CHF) to >400 W / cm².

[0033] 2. Collaborative design of gradient porosity and low thermal conductivity coating: Coating composition: Boron nitride (BN) as thermal insulation layer (thickness 10μm) + yttrium oxide This anti-corrosion coating is applied to the stainless steel wire surface via a plasma spray process. A pore gradient runs along the heat pipe axis, with the pore density in the refill zone increasing from the evaporator to the condenser (30% → 50%) to meet the reflow requirements. The coating has a temperature resistance of >1000°C and a lifespan of >15 years (compared to a conventional coating lifespan of <5 years). The pore gradient reduces reflow resistance, increasing the refill rate to 0.5 mL / (s•cm²).

[0034] 3. Local Failure Redundancy Mechanism: Zoned Thermal Isolation: A coating blocks lateral heat conduction between the evaporation zone and the refill zone, limiting localized dry-out or boiling failures to the evaporation zone. Independent Refill Path: The refill zone and evaporation zone are separated by distinct pore networks, ensuring that the working fluid can still flow back through the surviving zone in the event of a localized failure. After a localized failure, the heat pipe retains >60% of its heat transfer capacity; the system can operate continuously for >48 hours under extreme operating conditions (compared to <2 hours for traditional heat pipes).

[0035] 4. Coating Interface Strengthening Process: Transition Layer Design: A NiCrAlY alloy transition layer (5μm thick) is added between the coating and the stainless steel substrate. Laser remelting enhances the interfacial bonding strength to >50MPa. This improves the coating's thermal shock resistance by 80% (cycles >500, ΔT = 800°C), preventing blockage of the refill channel caused by coating peeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0037] Figure 1 It is a composite braided structure diagram; Figure 2 Schematic diagram of heat pipe failure caused by local boiling of the heat pipe; Figure 3 This is the workflow diagram of evaporation-liquid rehydration separation. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0039] Understandably, the fundamental problem of the capillary limit is that in traditional homogeneous wire meshes, evaporation and refilling of the working fluid share the same pore network. When the heat load increases, the evaporation rate exceeds the refill rate driven by capillary forces, leading to depletion (drying out) of the working fluid at the evaporation end. The logic for circumventing the boiling limit is that in conventional wire meshes, high heat flux causes a sudden temperature rise at the evaporation end, causing the working fluid to boil violently in an overheated state, bubbles clogging the pores and triggering thermal stress failure of the material. The design significance of failure redundancy is that once a traditional heat pipe partially dries out, the steam cannot condense and reflux, causing overall failure.

[0040] In order to eliminate the above defects, this embodiment provides a dual-heat-conducting high-temperature heat pipe, which has a composite capillary wick braided with low-thermal-conductivity-coated stainless steel wire 100 and conventional stainless steel wire 200, thereby forming alternatingly distributed evaporation zones and liquid replenishment zones.

[0041] Therefore, due to the low thermal conductivity (<0.5W / (m•K)), the working fluid on the surface of the low thermal conductivity coated wire mesh is difficult to evaporate, and is therefore specifically used for fluid replenishment. Even if the adjacent area reaches the capillary limit, the coated wire mesh can still continue to transport liquid working fluid through capillary force; the coated wire mesh reduces the lateral conduction of heat to the non-evaporation area (thermal conductivity is reduced by 80%), so that the heat is concentrated in the high thermal conductivity stainless steel wire mesh area for directional transmission, avoiding local temperature rise and suppressing abnormal boiling of the working fluid; through zoning design, the evaporation failure area is physically isolated from the fluid replenishment survival area, ensuring the survival of some functions.

[0042] This invention utilizes a composite woven structure of low-thermal-conductivity coated wire mesh 100 and conventional wire mesh 200 to fundamentally separate the evaporation and rehydration functions, addressing heat pipe failure issues caused by capillary and boiling limits. Its core benefits lie in: 1. Dry-out resistance: Rehydration is maintained even after the capillary limit is triggered, delaying failure; 2. Overheating resistance: Localized boiling is suppressed, improving high-temperature reliability; and 3. Failure tolerance: A robust design ensures that "partial failure does not equal overall failure."

[0043] Specifically, if Figure 1 As shown, the evaporation zone is made of conventional stainless steel wire mesh (uncoated), providing high thermal conductivity and promoting rapid evaporation of the working fluid. The refill zone is made of stainless steel wire mesh coated with a low-thermal-conductivity ceramic coating, which inhibits heat conduction and maintains a stable return flow of the liquid working fluid. The low-thermal-conductivity ceramic coating is preferably 10-30μm thick.

[0044] The composite braided structure utilizes a plain weave process, with stainless steel mesh coated with a low-thermal-conductivity ceramic coating and conventional stainless steel mesh alternating in a ratio of 1:1 to 1:5. In other words, each coated wire is separated by one to five conventional wires. The pore diameter in the evaporation zone is 50-80 μm, allowing for fluid evaporation and vapor diffusion. The pore diameter in the rehydration zone is 30-50 μm, allowing for preferential capillary transport of liquid fluid. In other words, the gaps between the conventional stainless steel mesh are 50-80 μm, while the gaps between the stainless steel mesh coated with a low-thermal-conductivity ceramic coating are 30-50 μm. Preferably, the stainless steel mesh coated with a low-thermal-conductivity ceramic coating and the conventional stainless steel mesh are alternating in a ratio of 1:3.

[0045] In this embodiment, the low thermal conductivity ceramic coating is boron nitride (BN)-yttrium oxide Composite ceramic coating, achieved through plasma spraying process with high bonding strength and thermal isolation effect.

[0046] Specifically, the bottom layer of the low thermal conductivity ceramic coating is a NiCrAlY alloy transition layer to enhance the bonding between the coating and the stainless steel substrate; the middle layer is a boron nitride (BN) layer, which provides low thermal conductivity (2 W / (m•K)); the surface layer is yttrium oxide. layer to resist high temperature corrosion of sodium working fluid.

[0047] It should be noted that the NiCrAlY transition layer is combined with the laser remelting process to improve the interface bonding strength between the coating and the substrate.

[0048] Through the above settings, the thermal conductivity of the coating is reduced to 0.5 W / (m•K), reducing the heat absorption of the rehydration area; the bonding strength between the coating and the substrate is greater than 50 MPa (ASTM C633 standard); in a sodium working fluid environment at 1000℃, the coating life is greater than 15 years. Preferably, the thickness of the NiCrAlY alloy transition layer is 5μm, the thickness of the boron nitride (BN) layer is 10μm, and the thickness of the yttrium oxide layer is 10μm. Layer thickness 5 μm.

[0049] It is worth noting that if Figure 3 As shown, the evaporation-liquid refill separation process of this embodiment is as follows: 1. Working fluid evaporation stage: Heat is rapidly conducted through the conventional wire mesh in the evaporation zone, and the liquid sodium working fluid evaporates in the pores (evaporation rate > 0.4 mL / (s•cm²)); the vapor diffuses upward through the pores in the evaporation zone to the condensation end.

[0050] 2. Working fluid rehydration stage: Liquid sodium at the condensation end flows back through the coated screen in the rehydration area. Due to the low thermal conductivity of the coating, the temperature in the rehydration area is lower than that in the evaporation area, and the working fluid remains in liquid form. The rehydration rate is >0.5 mL / (s•cm²), effectively offsetting the evaporation consumption.

[0051] 3. Fault-tolerance mechanism for extreme operating conditions: When the evaporation zone reaches the capillary limit locally (insufficient fluid replenishment), the adjacent fluid replenishment zone maintains liquid fluid transportation due to the low temperature, delaying overall drying. If the evaporation zone reaches the boiling limit (bubble blockage), the independent pores in the fluid replenishment zone can still maintain partial fluid circulation.

[0052] The composite weaving of low-thermal-conductivity coated wire mesh and conventional wire mesh achieves physical separation of evaporation and rehydration functions. Through material innovation (boron nitride-yttrium oxide coating) and structural optimization (alternating weave pores), the capillary and boiling limits are significantly improved, while also providing redundancy against localized failures in the heat pipe, providing a highly reliable thermal management solution for high-temperature applications such as nuclear reactors and spacecraft.

[0053] In this embodiment, the thermal conductivity of the stainless steel wire with low thermal conductivity coating is less than 0.5 W / (m·K), and the thermal conductivity of the conventional stainless steel wire is greater than 10 W / (m·K). Preferably, the thermal conductivity of the stainless steel wire with low thermal conductivity coating is less than 0.5 W / (m·K), and the thermal conductivity of the conventional stainless steel wire is greater than 15 W / (m·K).

[0054] 1. This composite braided capillary wick structure alternates low-thermal-conductivity coated stainless steel wire (thermal conductivity <0.5 W / (m•K)) with conventional stainless steel wire (thermal conductivity >15 W / (m•K)) in a specific ratio, creating a physical separation between the evaporation zone (conventional wire) and the refill zone (coated wire). The evaporation zone has pores with a diameter of 50-80 μm, ensuring efficient evaporation of the working fluid. The refill zone has pores with a diameter of 30-50 μm, prioritizing the transport of liquid working fluid through capillary forces. The low thermal conductivity of the refill zone maintains a low temperature, preventing complete evaporation of the surrounding alkali metal. Even at the capillary limit, the refill capacity remains >60%, increasing the critical heat flux (CHF) to >400 W / cm².

[0055] 2. Collaborative design of gradient porosity and low thermal conductivity coating: Coating composition: Boron nitride (BN) as thermal insulation layer (thickness 10μm) + yttrium oxide The anti-corrosion coating (μm thick) is applied to the stainless steel wire surface via a plasma spray process. A pore gradient runs along the heat pipe axis, with the pore density in the refill zone increasing from the evaporator to the condenser (30% → 50%) to meet the reflow requirements. The coating has a temperature resistance of >1000°C and a lifespan of >15 years (compared to a conventional coating lifespan of <5 years). The pore gradient reduces reflow resistance, increasing the refill rate to 0.5 mL / (s•cm²).

[0056] 3. Local Failure Redundancy Mechanism: Zoned Thermal Isolation: A coating blocks lateral heat conduction between the evaporation zone and the refill zone, limiting localized dry-out or boiling failures to the evaporation zone. Independent Refill Path: The refill zone and evaporation zone are separated by distinct pore networks, ensuring that the working fluid can still flow back through the surviving zone in the event of a localized failure. After a localized failure, the heat pipe retains >60% of its heat transfer capacity; the system can operate continuously for >48 hours under extreme operating conditions (compared to <2 hours for traditional heat pipes).

[0057] 4. Coating Interface Strengthening Process: Transition Layer Design: A NiCrAlY alloy transition layer (5μm thick) is added between the coating and the stainless steel substrate. Laser remelting enhances the interfacial bonding strength to >50MPa. This improves the coating's thermal shock resistance by 80% (cycles >500, ΔT = 800°C), preventing blockage of the refill channel caused by coating peeling.

[0058] The foregoing description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be readily conceived by a person skilled in the art within the technical scope disclosed herein are intended to be encompassed within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A high-temperature heat pipe with dual heat conduction, characterized in that: It has a composite capillary wick made by weaving low thermal conductivity coated stainless steel wire and regular stainless steel wire to form alternating evaporation zones and liquid replenishment zones; Among them, the evaporation area is a conventional stainless steel wire mesh, and the liquid replenishment area is a stainless steel wire mesh coated with a low thermal conductivity ceramic coating.

2. The dual-heat-conducting high-temperature heat pipe according to claim 1, characterized in that: The composite woven structure adopts a plain weave process, and the stainless steel wire mesh coated with low thermal conductivity ceramic coating and the conventional stainless steel wire mesh are arranged alternately in a ratio of 1:1 to 1:

5.

3. The dual-heat-conducting high-temperature heat pipe according to claim 2, characterized in that: The gap of conventional stainless steel wire mesh is 50-80μm, and the gap of stainless steel wire mesh coated with low thermal conductivity ceramic coating is 30-50μm.

4. The dual-heat-conducting high-temperature heat pipe according to claim 2, characterized in that: The stainless steel wire mesh coated with low thermal conductivity ceramic coating and the regular stainless steel wire mesh are arranged alternately in a ratio of 1:

3.

5. The dual-heat-conducting high-temperature heat pipe according to claim 1, characterized in that: Low thermal conductivity ceramic coating is boron nitride (BN)-yttrium oxide Composite ceramic coating, which achieves high bonding strength and thermal isolation effect through plasma spraying process; Among them, the bottom layer of the low thermal conductivity ceramic coating is a NiCrAlY alloy transition layer, the middle layer is a boron nitride (BN) layer, and the surface layer is yttrium oxide. layer.

6. The dual-heat-conducting high-temperature heat pipe according to claim 5, characterized in that: The NiCrAlY transition layer is combined with laser remelting process to improve the interface bonding strength between the coating and the substrate.

7. The dual-heat-conducting high-temperature heat pipe according to claim 5, characterized in that: The thickness of NiCrAlY alloy transition layer is 5μm, the thickness of boron nitride (BN) layer is 10μm, and the thickness of yttrium oxide is 10μm. Layer thickness 5 μm.

8. The dual-heat-conducting high-temperature heat pipe according to claim 1, characterized in that: The thermal conductivity of low thermal conductivity coated stainless steel wire is <10W / (m•K), while the thermal conductivity of conventional stainless steel wire is >10W / (m•K).

9. The dual-heat-conducting high-temperature heat pipe according to claim 8, characterized in that: The thermal conductivity of low thermal conductivity coated stainless steel wire is <0.5W / (m•K), and the thermal conductivity of conventional stainless steel wire is >15W / (m•K).

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