Wide-temperature-range self-adaptive multi-cavity heat pipe

Abstract

The invention relates to the field of heat pipes, in particular to a wide-temperature-range self-adaptive multi-cavity heat pipe which comprises an outer pipe shell, at least two independent working medium cavities and a cavity located between every two adjacent working medium cavities are formed in the outer pipe shell, and the different working medium cavities are filled with working media of different working temperature ranges. Each working medium cavity is divided into an evaporation section, a heat insulation section and a condensation section, the heat insulation section and the condensation section of each working medium cavity are smooth inner walls, a capillary structure is fixed to the inner wall of the evaporation section of each working medium cavity, the evaporation section of each working medium cavity is connected with a heat source, and the inner wall of the condensation section of each working medium cavity is coated with a hydrophobic layer. The heat pipe is designed to be of a one-pipe multi-cavity structure, different working medium cavities are filled with working media of different working temperature areas, the working media of the different working temperature areas can be automatically switched according to the environment temperature, and therefore the wide temperature range requirement of the heat pipe is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat pipes, and in particular relates to a wide temperature range adaptive multi-cavity heat pipe. Background Art

[0002] Heat pipes have been widely used in thermal management of aerospace devices (such as satellites and spacecraft) due to their efficient heat transfer performance. However, traditional heat pipes rely on a single working fluid for phase change heat transfer, which works well within the working temperature range, but significantly decreases in heat transfer performance beyond the working temperature range, making it difficult to meet the requirements of a wide temperature range, especially in spacecraft, which may cause equipment overheating or cooling failure.

[0003] With the continuous development of aerospace technology, there are more and more demands for spacecraft to operate in extreme environments. Especially in the case of frequent orbit changes (such as low earth orbit) or drastic fluctuations in ambient temperature (such as the huge temperature difference between day and night on the lunar surface), the demand for thermal management equipment with wide temperature range adaptability is increasing. Summary of the invention

[0004] In view of this, the present invention aims to solve the problem of limited heat transfer performance of traditional heat pipes in extreme environments, and provide a wide temperature range adaptive multi-cavity heat pipe to meet the thermal management needs of complex scenarios such as aerospace and polar scientific research.

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows: A wide temperature range adaptive multi-cavity heat pipe comprises an outer tube shell, at least two independent working fluid cavities and a cavity located between two adjacent working fluid cavities are formed inside the outer tube shell, working fluids in different working temperature zones are filled in different working fluid cavities, each working fluid cavity is respectively divided into an evaporation section, an insulation section and a condensation section, the insulation section and the condensation section of each working fluid cavity are smooth inner walls, a capillary structure is fixed on the inner wall of the evaporation section of each working fluid cavity, the evaporation section of each working fluid cavity is respectively connected to a heat source, and a hydrophobic layer is deposited on the inner wall of the condensation section of each working fluid cavity.

[0006] Furthermore, there are two working fluid cavities, the working temperature range of the working fluid filled in one working fluid cavity is -40°C to 100°C, and the working temperature range of the working fluid filled in the other working fluid cavity is 100°C to 350°C.

[0007] Furthermore, the working fluid in the working temperature range of -40°C to 100°C is ethanol or ammonia, and the working fluid in the working temperature range of 100°C to 350°C is water or naphthalene.

[0008] Furthermore, the capillary structure is a metal wire mesh.

[0009] Furthermore, the outer tube shell is a double-layer structure, including a high-strength outer layer and a high-thermal conductivity inner layer, and the high-strength outer layer and the high-thermal conductivity inner layer are connected by brazing.

[0010] Furthermore, the high-strength outer layer is made of titanium alloy, stainless steel or carbon fiber material, and the high-thermal conductivity inner layer is made of aluminum alloy, copper or silver material.

[0011] Furthermore, the hydrophobic layer is a fluoride coating, and the fluoride coating is deposited on the inner wall of the condensation section by a physical vapor deposition method.

[0012] Furthermore, the cavity is filled with heat insulating material.

[0013] Furthermore, the thermal insulation material is ceramic fiber or polyurethane foam.

[0014] Compared with the prior art, the invention can achieve the following beneficial effects: The present invention designs the heat pipe as a one-tube multi-cavity structure, and fills different working fluid cavities with working fluids in different working temperature zones, so that the working fluids in different working temperature zones can be automatically switched according to the ambient temperature, thereby achieving the wide temperature range adaptability of the heat pipe. Through the dual effects of capillary structure design and hydrophobic layer coating, the working fluid can achieve efficient circulation and reflux in the evaporation and condensation stages, ensuring stable heat transfer performance at all times in an environment with drastic temperature changes. The present invention can automatically adapt to changes in ambient temperature under variable temperature conditions, maintain efficient heat transfer performance, and improve the reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 It is a schematic diagram of the structure of the wide temperature range adaptive multi-cavity heat pipe described in Example 1 of the present invention.

[0016] Explanation of the accompanying drawings: outer tube shell 1, high-strength outer layer 1-1, high thermal conductivity inner layer 1-2, low-temperature working fluid cavity evaporation section 2, low-temperature working fluid cavity insulation section 3, low-temperature working fluid cavity condensation section 4, low-temperature working fluid 5, medium-temperature working fluid cavity evaporation section 6, medium-temperature working fluid cavity insulation section 7, medium-temperature working fluid cavity condensation section 8, medium-temperature working fluid 9, cavity 10, low-temperature working fluid cavity 11, medium-temperature working fluid cavity 12, hydrophobic layer 13. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0018] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0019] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0020] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0021] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0022] The invention provides a wide temperature range adaptive multi-cavity heat pipe, including an outer tube shell, at least two independent working fluid cavities and a cavity located between two adjacent working fluid cavities are formed inside the outer tube shell, each working fluid cavity is filled with working fluid, but the working temperature zone of the working fluid filled in each working fluid cavity is different, so that each working fluid cavity operates in a different temperature range, and two adjacent working fluid cavities are separated by the cavity, which is a vacuum cavity formed after vacuuming, and plays a heat insulation role, ensuring that each working fluid works efficiently within its own temperature range without interfering with each other.

[0023] The present invention innovatively designs the heat pipe into a one-tube multi-cavity structure, and fills each working medium cavity with working medium of different working temperature zones. Through this structural design, working medium of different working temperature zones can be automatically switched according to the ambient temperature, thereby realizing the wide temperature range requirement of the heat pipe and effectively improving the adaptability and heat transfer efficiency of the heat pipe in extreme environments. The present invention can effectively overcome the problem of poor temperature adaptability of existing heat pipes, expand the application scenarios of heat pipes, and is particularly suitable for environments with large temperature changes.

[0024] Taking two working fluid cavities as an example, the specific structure of the wide temperature range adaptive multi-cavity heat pipe provided by the embodiment of the present invention is described in detail below. The same can be said for heat pipes with three or more working fluid cavities.

[0025] Example 1 like Figure 1 As shown, the wide temperature range adaptive multi-cavity heat pipe provided by Example 1 of the present invention includes an outer tube shell 1. The outer tube shell 1 adopts a double-layer structure, including a high-strength outer layer 1-1 and a high thermal conductivity inner layer 1-2. The high thermal conductivity inner layer 1-2 is made of a high thermal conductivity material, selected from aluminum alloy (grade 6061, 6063), copper, and silver to ensure excellent heat conduction efficiency; the high-strength outer layer 1-1 is made of a high-strength material, selected from titanium alloy, stainless steel, and carbon fiber material to provide the necessary structural strength and pressure resistance. The thickness of the high thermal conductivity inner layer 1-2 is controlled between 1mm and 5mm to ensure sufficient thermal conductivity, while the thickness of the high-strength outer layer 1-1 is between 0.5mm and 3mm to take into account both structural strength and weight. The high-strength outer layer 1-1 is connected to the high thermal conductivity inner layer 1-2 by low-temperature brazing to ensure a firm bond between the layers and overall durability.

[0026] A low-temperature working fluid cavity 11 and a medium-temperature working fluid cavity 12 are processed inside the outer tube shell 1, and a cavity 10 is processed in the area between the low-temperature working fluid cavity 11 and the medium-temperature working fluid cavity 12 inside the outer tube shell 1. The low-temperature working fluid cavity 11, the medium-temperature working fluid cavity 12 and both ends of the cavity 10 are sealed respectively, and the sealing methods include but are not limited to laser welding, electron beam welding or brazing.

[0027] The low-temperature working medium cavity 11 is used as a low-temperature heat pipe, and the medium-temperature working medium cavity 12 is used as a medium-temperature heat pipe. The double-cavity heat pipe of this embodiment 1 can work in both a low-temperature environment and a medium-temperature environment.

[0028] The cryogenic working fluid cavity 11 is filled with a cryogenic working fluid 5 having an operating temperature range of -40°C to 100°C. For example, the cryogenic working fluid 5 is ethanol or ammonia, which can realize efficient evaporation and condensation cycles in a low-temperature environment. Ethanol or ammonia is selected as the cryogenic working fluid 5 because ethanol or ammonia has a low boiling point and good latent heat of evaporation at low temperatures, which enables ethanol or ammonia to efficiently perform phase change heat transfer in a low-temperature environment, thereby ensuring efficient operation of the heat pipe under low-temperature conditions. In addition, ethanol has low toxicity and good chemical stability, and ammonia has a very high evaporation efficiency under extremely cold conditions due to its extremely low boiling point. These characteristics make acetone, methanol or ammonia superior to other optional working fluids, and are particularly suitable for low-temperature heat transfer requirements in special environments such as aerospace and polar regions.

[0029] The medium-temperature working medium cavity 12 is filled with a medium-temperature working medium 9 having a working temperature range of 100°C to 350°C. For example, the medium-temperature working medium 9 is water or naphthalene, which can maintain stable heat transfer performance in a medium-temperature environment. Water has a high specific heat capacity and latent heat of evaporation, and can effectively absorb and release heat in a medium-temperature environment to ensure a stable heat transfer effect; and naphthalene is suitable for a higher medium-temperature range due to its high boiling point and chemical stability, and can achieve efficient phase change heat transfer in a medium-temperature environment.

[0030] After the working fluid is injected into the low-temperature working fluid cavity 11 and the medium-temperature working fluid cavity 12 , the injection ports are sealed by laser welding or pressure sealing technology.

[0031] The low-temperature working fluid cavity 11 is divided into a low-temperature working fluid cavity evaporation section 2, a low-temperature working fluid cavity insulation section 3 and a low-temperature working fluid cavity condensation section 4, and the medium-temperature working fluid cavity 12 is divided into a medium-temperature working fluid cavity evaporation section 6, a medium-temperature working fluid cavity insulation section 7 and a medium-temperature working fluid cavity condensation section 8; wherein, the inner walls of the low-temperature working fluid cavity evaporation section 2 and the medium-temperature working fluid cavity evaporation section 6 are fixed with a capillary structure, which is a metal wire mesh woven with metal wires, to ensure that the working fluid can quickly flow back to the evaporation area, thereby significantly improving the heat transfer efficiency; the low-temperature working fluid cavity insulation section 3, the low-temperature working fluid cavity condensation section 4, the medium-temperature working fluid cavity insulation section 7 and the medium-temperature working fluid cavity condensation section 8 adopt smooth inner walls, which can make the reflux of the working fluid smoother and avoid uneven flow or retention caused by rough surface or complex structure; the inner walls of the low-temperature working fluid cavity condensation section 4 and the medium-temperature working fluid cavity condensation section 8 are also coated with a hydrophobic layer 13, which adopts a fluoride coating, and the fluoride coating is deposited on the inner wall of the condensation section by physical vapor deposition. The thickness of the fluoride coating is controlled between 0.5μm and 5μm, and the contact angle of the hydrophobic layer is greater than 110°, ensuring that the inner wall of the condensation section has excellent hydrophobic properties and promotes effective reflux of the working fluid. Through heat treatment processes, such as high-temperature tempering or curing treatment, the adhesion between the coating and the substrate is improved, and the wear resistance and corrosion resistance of the hydrophobic layer in long-term use are enhanced.

[0032] The cavity 10 is filled with heat-insulating materials, such as ceramic fiber or polyurethane foam, to further isolate the low-temperature working medium cavity 11 from the medium-temperature working medium cavity 12 to prevent thermal interference between the low-temperature working medium 5 and the medium-temperature working medium 9 .

[0033] The working principle of the present embodiment 1 is as follows: the low-temperature working fluid cavity evaporation section 2 and the medium-temperature working fluid cavity evaporation section 6 are respectively connected to the heat source. When the heat source is in the low-temperature zone (-40°C~100°C), the low-temperature working fluid cavity 11 (i.e., the low-temperature heat pipe) starts to work, and the heat of the heat source is transmitted to the low-temperature working fluid cavity evaporation section 2 through the outer tube shell 1. The low-temperature working fluid 5 absorbs heat and evaporates to become a gas. The steam pressure of the low-temperature working fluid cavity evaporation section 2 is higher than that of the low-temperature working fluid cavity condensation section 4. Therefore, a pressure difference is formed at both ends of the low-temperature working fluid cavity 11. The pressure difference drives the steam from the low-temperature working fluid cavity evaporation section 2 through the low-temperature working fluid cavity insulation section 3 to the low-temperature working fluid cavity condensation section 4. The steam is heated in the low-temperature working fluid cavity condensation section 4. Condensed into liquid and releases latent heat of vaporization. Liquid low-temperature working fluid 5 flows back to low-temperature working fluid cavity evaporation section 2 under the action of capillary force, so that low-temperature working fluid 5 completes a low-temperature flow cycle; when the heat source is in the medium temperature zone (100℃~350℃), the medium temperature working fluid cavity 12 (i.e. medium temperature heat pipe) starts to work, and the heat of the heat source is transmitted to the medium temperature working fluid cavity evaporation section 6 through the outer tube shell 1. The medium temperature working fluid 9 absorbs heat and evaporates into gas. The steam pressure of the medium temperature working fluid cavity evaporation section 6 is higher than that of the medium temperature working fluid cavity condensation section 8, so a pressure difference is formed at both ends. The pressure difference drives the steam from the medium temperature working fluid cavity evaporation section 6 through the medium temperature working fluid cavity insulation section 7 to the medium temperature working fluid cavity condensation section 8. The steam condenses into liquid in the medium temperature working fluid cavity condensation section 8 and releases latent heat of vaporization. The steam working fluid 9 in the tube flows back to the medium temperature working fluid cavity evaporation section 6 under the action of capillary force, so that the working fluid completes a medium temperature flow cycle.

[0034] In order to verify the high efficiency and adaptability of the present invention in a wide temperature range, the following experimental tests were conducted: Test conditions: Heat source temperature range: -40℃ to 350℃; Working fluid chamber configuration: The low temperature chamber is filled with ethanol, and the working temperature range is -40℃ to 100℃; The high temperature chamber is filled with water and the operating temperature range is 100°C to 350°C.

[0035] The external environment simulates the temperature difference between day and night on the moon (-173℃ to 127℃).

[0036] Performance indicators: heat transfer efficiency and thermal resistance (unit: K / W).

[0037] Test objects: multi-cavity heat pipe, single-cavity single-working medium heat pipe, and series-connected multi-heat pipe solution of the present invention.

[0038] Experimental Results

[0039] Conclusion: The present invention exhibits stable and efficient heat transfer performance over the entire temperature range, and is superior to the comparative technology especially at low and high temperature conditions.

[0040] Thermal resistance remains in the range of 0.2-0.3 K / W, significantly lower than other solutions, demonstrating its superior heat pipe design and fluid management performance. The above simulation results show that the high-efficiency heat transfer capability of the present invention in a wide temperature range is significantly better than that of the prior art. In addition, the application verification of the present invention in the thermal control system of spacecraft shows that it exhibits good adaptability and stability in conditions with large temperature differences such as low earth orbit and lunar environment, and can effectively meet the stringent requirements of space missions.

[0041] The present invention can adapt to more complex temperature environments and application requirements when using multiple working fluid chamber structures. For example, multiple working fluids, such as ammonia, water, acetone or methane, can be filled in different working fluid chambers to achieve a wider range of temperature adaptability. Ammonia is suitable for low temperature ranges, water is suitable for medium temperature environments, and acetone and methane can be further expanded to more special temperature requirements, thereby improving the overall flexibility and application breadth of the heat pipe.

[0042] For example, it is applied to spacecraft thermal control systems: In spacecraft thermal control systems, the multi-cavity design of different working fluids can cope with extreme temperature differences, such as low-Earth orbit and deep space exploration environments, and maintain the stability and efficiency of the system by automatically switching different working fluids. Another example is applied to extreme ground environments: In extreme ground environments such as polar research stations, the combination of working fluids such as ammonia and water can work alternately in extremely cold and relatively warm seasons, ensuring efficient operation of the equipment throughout the year.

[0043] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0044] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A wide temperature range adaptive multi-cavity heat pipe, characterized in that: The invention comprises an outer tube shell, at least two independent working fluid chambers and a cavity located between two adjacent working fluid chambers are formed inside the outer tube shell, working fluids in different working temperature zones are filled in different working fluid chambers, each working fluid chamber is respectively divided into an evaporation section, an insulation section and a condensation section, the insulation section and the condensation section of each working fluid chamber have smooth inner walls, a capillary structure is fixed on the inner wall of the evaporation section of each working fluid chamber, the evaporation section of each working fluid chamber is respectively connected to a heat source, and a hydrophobic layer is deposited on the inner wall of the condensation section of each working fluid chamber.

2. The wide temperature range adaptive multi-cavity heat pipe according to claim 1, characterized in that: There are two working fluid cavities. The working temperature range of the working fluid filled in one working fluid cavity is -40°C to 100°C, and the working temperature range of the working fluid filled in the other working fluid cavity is 100°C to 350°C.

3. The wide temperature range adaptive multi-cavity heat pipe according to claim 2, characterized in that: The working fluid in the working temperature range of -40°C to 100°C is ethanol or ammonia, and the working fluid in the working temperature range of 100°C to 350°C is water or naphthalene.

4. The wide temperature range adaptive multi-cavity heat pipe according to claim 1, characterized in that: The capillary structure is a wire mesh.

5. The wide temperature range adaptive multi-cavity heat pipe according to claim 1, characterized in that: The outer tube shell is a double-layer structure, including a high-strength outer layer and a high-thermal conductivity inner layer, and the high-strength outer layer and the high-thermal conductivity inner layer are connected by brazing.

6. The wide temperature range adaptive multi-cavity heat pipe according to claim 5, characterized in that: The high-strength outer layer is made of titanium alloy, stainless steel or carbon fiber material, and the high-thermal conductivity inner layer is made of aluminum alloy, copper or silver material.

7. The wide temperature range adaptive multi-cavity heat pipe according to claim 1, characterized in that: The hydrophobic layer is a fluoride coating, which is deposited on the inner wall of the condensation section by a physical vapor deposition method.

8. The wide temperature range adaptive multi-cavity heat pipe according to claim 1, characterized in that: The cavity is filled with heat insulating material.

9. The wide temperature range adaptive multi-cavity heat pipe according to claim 8, characterized in that: The insulation material is ceramic fiber or polyurethane foam.

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