A method for manufacturing a composite liquid-absorbing core curved high-temperature heat pipe

Abstract

The present invention discloses a method for manufacturing a composite liquid-wick curved high-temperature heat pipe. The method comprises the following steps: first, utilizing additive manufacturing technology, using metal powder as the raw material for the heat pipe additive manufacturing, to manufacture straight and curved partial heat pipe assemblies, each comprising a heat pipe shell and a composite liquid-wick structure; second, utilizing laser welding technology to assemble the curved and straight partial heat pipe assemblies; and finally, subjecting the prepared heat pipe to vacuum extraction, injection of a working medium, and other processing steps to obtain a composite liquid-wick curved heat pipe with excellent heat transfer performance. The method of the present invention is simple to operate, has low production costs, high production efficiency, and the finished heat pipe has excellent heat transfer performance. The method can be applied to fields such as energy and power, petrochemicals, and construction engineering.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature heat pipes, and in particular relates to a method for manufacturing a composite liquid-absorbing core curved high-temperature heat pipe. Background Art

[0002] Traditional heat pipes often use single-structure wicks, such as wire mesh, grooved, and sintered metal powder. These heat pipes are simple in structure, easy to process, and low in manufacturing cost. However, to maintain internal fluid recirculation within the heat pipe, the wick structure must possess good permeability, low fluid flow resistance, and strong capillary force. Single-structure wicks struggle to meet these requirements. For example, grooved wicks exhibit good overall permeability and low fluid flow resistance, but also suffer from weak capillary force. Sintered metal powder wicks, on the other hand, exhibit strong capillary force, but low overall permeability and high fluid flow resistance.

[0003] A composite wick combines two or more single-structure wicks to leverage the strengths of each to enhance heat pipe performance. For example, a composite wick that combines a channel-type and a sintered wick combines the capillary strength of a sintered wick with the liquid reflux benefits of a channel-type wick. This effectively boosts the heat transfer limit of a heat pipe and optimizes its gravity-resistant performance.

[0004] High-temperature heat pipes typically operate at temperatures exceeding 450°C. They typically utilize alkali metals such as potassium, sodium, and lithium as internal circulating fluids and are used for electronic component cooling, aircraft thermal protection, and small advanced nuclear power systems. These applications require shorter high-temperature heat pipes, which means bending straight heat pipes to accommodate compact applications.

[0005] Currently, the manufacturing method of curved high-temperature heat pipes usually adopts manual operation or machine processing. The preparation process is cumbersome, time-consuming, and costly. It is difficult to ensure the quality and stability of the heat pipes, and it is difficult to complete the processing and manufacturing of curved heat pipes with composite liquid wick structures. Summary of the Invention

[0006] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for manufacturing a composite liquid-absorbing core curved high-temperature heat pipe, which innovatively combines the additive manufacturing process to achieve the preparation of a large aspect ratio, high-performance curved high-temperature heat pipe.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for manufacturing a composite liquid-absorbing wick curved high-temperature heat pipe, characterized by comprising the following steps:

[0009] S1. Design the curved heat pipe structure, select the heat pipe additive manufacturing material and the geometric parameters of the composite wick curved high-temperature heat pipe, draw the structural model to be printed, and transfer it to the additive manufacturing equipment;

[0010] S2. Prepare heat pipe additive manufacturing materials, use metal powder as the raw material of the heat pipe additive manufacturing material, pretreat the metal powder material, and load the pretreated metal powder into the additive manufacturing equipment;

[0011] S3. Using additive manufacturing equipment, by selecting appropriate additive process parameters, the additive manufacturing material and the composite wick are integrated into a local heat pipe assembly having a predetermined design shape. The local heat pipe assembly includes a local heat pipe assembly connection transition section to facilitate pre-fixed splicing of different local heat pipe assemblies.

[0012] S4. Immerse and clean the local heat pipe assembly using a 75°C water-based cleaning agent, a room temperature acid cleaning agent, and a room temperature alcohol solvent cleaning agent to remove oil and impurities inside the local heat pipe assembly;

[0013] S5. Using laser welding technology, in an inert gas atmosphere, assemble and weld the local heat pipe components to obtain an integrally formed composite liquid-absorbing core curved high-temperature heat pipe;

[0014] S6, filling the composite wick bent high-temperature heat pipe with the internal working fluid of the heat pipe, and then performing a rough vacuum operation to maintain the internal pressure of the heat pipe within 10Pa;

[0015] S7, heat and exhaust the composite liquid wick bent high temperature heat pipe, heat it at 250℃, 550℃ and 750℃ for a preset time respectively, and then perform vacuum operation again to maintain the internal pressure of the heat pipe at 10 -4 Pa, the heat pipe is sealed using laser welding technology to complete the production of the composite liquid-absorbing core curved high-temperature heat pipe.

[0016] The metal powder of the heat pipe additive manufacturing material is stainless steel metal powder, titanium alloy powder, copper alloy powder, nickel alloy powder or oxide dispersion strengthened alloy powder.

[0017] The geometric parameters of the composite liquid wick curved high-temperature heat pipe include the composite liquid wick type, the heat pipe diameter, the heat pipe length, the heat pipe wall thickness, and the bending radius of the heat pipe bending section.

[0018] The powder material pretreatment includes spraying adhesive and screening metal powder.

[0019] The additive process parameters include the release rate of the additive manufacturing material, the heating temperature of the additive manufacturing material, the laser power of the additive manufacturing equipment, and the release strategy of the inert protective gas of the additive manufacturing equipment during the additive process.

[0020] The additive manufacturing equipment includes additive manufacturing equipment using laser cladding deposition technology or laser selective melting technology.

[0021] The working fluid inside the heat pipe contains alkali metals such as sodium, potassium or lithium.

[0022] The outer shape of the curved heat pipe includes one or more of a straight shape, an L shape, a U shape, and an S shape.

[0023] The inert gas atmosphere protection environment is a nitrogen atmosphere environment, a helium atmosphere environment or an argon atmosphere environment.

[0024] The local heat pipe assembly has a length of 10 cm to 120 cm, an outer diameter of φ10 mm to φ40 mm, a wall thickness of 0.5 mm to 2 mm, a bending angle of 0° to 120°, and a bending radius of 50 mm to 500 mm.

[0025] The types of composite liquid absorbent cores include a combination of channel type and sintered powder type, a combination of channel type and wire mesh type, a combination of trunk type and wire mesh type, and a combination of trunk type and sintered powder type.

[0026] The groove type is characterized in that the grooves are formed together with the heat pipe wall by an additive method, the number of grooves is 20 to 100, the groove depth does not exceed half the thickness of the heat pipe wall, and the width is determined by the outer diameter of the heat pipe and the number of grooves, and is 0.1 mm to 0.5 mm.

[0027] The trunk type is formed by an additive method together with the heat pipe wall, the number of which is 1 to 6, and the cross-section of the trunk includes circular, elliptical, quadrilateral, and triangular.

[0028] The wire mesh is woven from metal warp and weft threads attached to the groove, and is produced together with the groove or trunk type by an additive method. The mesh count of the wire mesh is 100 to 800, and the number of layers is 1 to 5.

[0029] The sintered powder type is produced by an additive method together with a channel type or a trunk type, and has a thickness of 0.3 mm to 2 mm. The particle size of the sintered material powder is 30 μm to 200 μm.

[0030] The heat pipe has a length of 80cm to 400cm, an outer diameter of φ10mm to φ40mm, 1 to 4 bending sections, a length of 10cm to 100cm, a bending angle of 0° to 120°, and a bending radius of 50mm to 500mm.

[0031] Beneficial effects:

[0032] The present invention provides a method for manufacturing a composite liquid-wick curved high-temperature heat pipe, which realizes the manufacture of a composite liquid-wick curved heat pipe. The method innovatively combines the additive manufacturing process and integrally processes the heat pipe additive manufacturing material and the composite liquid-wick into a single piece, thereby realizing the preparation of a high-performance curved high-temperature heat pipe with a large aspect ratio. This enables the heat pipe to overcome the shortcomings of the previous single-type liquid-wick structural design, such as low heat transfer limit, poor isothermal performance, and weak anti-gravity performance. It improves the heat pipe's ability to achieve passive and efficient heat transfer in a compact space, and broadens the application scenarios of the heat pipe. At the same time, the additive technology and segmented production process can realize the combined application of multiple types of liquid-wicks, which helps to improve the flexibility of the heat pipe in the face of different heat source boundaries and cold trap conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Flow chart of the method of the present invention.

[0034] Figure 2 The figure is a schematic diagram of the overall structure of a composite liquid-absorbing core curved high-temperature heat pipe manufactured in a specific embodiment of the present invention.

[0035] Figure 3 for Figure 2 Schematic diagram of the partial structure of the composite liquid-absorbing core curved high-temperature heat pipe in the embodiment.

[0036] Figure 4 for Figure 2 Schematic diagram of the structure of a local heat pipe assembly of a composite liquid-absorbing core curved high-temperature heat pipe in an embodiment. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] The embodiment of the present invention discloses a method for manufacturing a composite liquid wick curved high temperature heat pipe, see Figure 1 , including the following steps:

[0039] S1. Design the curved heat pipe structure, select the heat pipe additive manufacturing material and the geometric parameters of the composite wick curved high-temperature heat pipe, draw the structural model to be printed, and transfer it to the additive manufacturing equipment;

[0040] S2. Prepare additive manufacturing materials, use metal powder as the raw material for heat pipe additive manufacturing, pretreat the metal powder material, and load the pretreated metal powder into the additive manufacturing equipment;

[0041] S3. Using additive manufacturing equipment, by selecting appropriate additive process parameters, the additive manufacturing material and the composite wick are integrally processed into a local heat pipe assembly having a predetermined design shape;

[0042] S4. Immerse and clean the local heat pipe assembly using a 75°C water-based cleaning agent, a room temperature acid cleaning agent, and a room temperature alcohol solvent cleaning agent for 30 minutes to remove oil and impurities inside the local heat pipe assembly;

[0043] S5. Using laser welding technology, in an inert gas atmosphere, assemble and weld the local heat pipe components to obtain an integrally formed composite liquid-absorbing core curved high-temperature heat pipe;

[0044] S6, filling the composite wick bent high-temperature heat pipe with the internal working fluid of the heat pipe, and then performing a rough vacuum operation to maintain the internal pressure of the heat pipe within 10Pa;

[0045] S7, heat and exhaust the composite liquid wick bent high temperature heat pipe, heat it at 250℃, 550℃ and 750℃ for 30 minutes respectively, and then perform vacuum operation again to maintain the internal pressure of the heat pipe at 10 -4 Pa, the heat pipe is sealed using laser welding technology to complete the production of the composite liquid-absorbing core curved high-temperature heat pipe.

[0046] In one embodiment, see Figure 2 , Figure 2 A schematic diagram of the overall structure of a composite wick curved high-temperature heat pipe manufactured in one embodiment of the present invention is shown. It consists of an additively manufactured straight local heat pipe assembly 1 and a curved local heat pipe assembly 2, joined by laser welding. The weld seam 3 left by the laser welding can be observed on the heat pipe wall.

[0047] See also Figure 3 , Figure 3 Draws Figure 2 Schematic diagram of the local structure of the composite liquid-absorbing core curved high-temperature heat pipe in the embodiment; along the heat pipe from the outside to the inside, there are the heat pipe wall 4, the channel type liquid-absorbing core 5, and the wire mesh type liquid-absorbing core 6.

[0048] In the embodiment, the heat pipe wall 4, the channel-type liquid absorbent core 5, and the wire mesh-type liquid absorbent core 6 are integrally formed by additive manufacturing, and the channel-type liquid absorbent core 5 and the wire mesh-type liquid absorbent core 6 together constitute a composite liquid absorbent core.

[0049] See also Figure 4 , Figure 4 Draws Figure 2 Schematic diagram of the structure of the local heat pipe assembly of the composite liquid-absorbing core curved high-temperature heat pipe in the embodiment; the local heat pipe assembly has a local heat pipe assembly connection transition section 7, which is convenient for pre-fixed splicing of different local heat pipe assemblies.

[0050] In the embodiment, the additive manufacturing material uses stainless steel metal powder, which is pretreated through the metal powder initial screening and adhesive spraying process, and then the laser selective melting technology is used to complete the integrated molding of the composite liquid-absorbing core curved high-temperature heat pipe local components.

[0051] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for manufacturing a composite wick curved high-temperature heat pipe, characterized in that: The following steps are involved: S1. Design the curved heat pipe structure, select the heat pipe additive manufacturing material and the geometric parameters of the composite wick curved high-temperature heat pipe, draw the structural model to be printed, and transfer it to the additive manufacturing equipment; The geometric parameters of the composite wick bent high-temperature heat pipe include the composite wick type, heat pipe diameter, heat pipe length, heat pipe wall thickness, and heat pipe bending radius; S2. Prepare heat pipe additive manufacturing materials, use metal powder as the raw material of the heat pipe additive manufacturing material, pretreat the metal powder material, and load the pretreated metal powder into the additive manufacturing equipment; S3. Using additive manufacturing equipment, by selecting appropriate additive process parameters, the additive manufacturing material and the composite wick are integrated into a local heat pipe assembly having a predetermined design shape. The local heat pipe assembly includes a local heat pipe assembly connection transition section to facilitate pre-fixed splicing of different local heat pipe assemblies. The additive manufacturing process parameters include the release rate of the additive manufacturing material during the additive manufacturing process, the heating temperature of the additive manufacturing material, the laser power of the additive manufacturing equipment, and the release strategy of the inert protective gas of the additive manufacturing equipment; The additive manufacturing equipment includes additive manufacturing equipment using laser cladding deposition technology or laser selective melting technology; S4. Immerse and clean the local heat pipe assembly in step S3 using a 75°C water-based cleaning agent, a room temperature acid cleaning agent, and a room temperature alcohol solvent cleaning agent to remove oil and impurities inside the local heat pipe assembly; S5. Using laser welding technology, in an inert gas atmosphere, assemble and weld the local heat pipe components to obtain an integrally formed composite liquid-absorbing core curved high-temperature heat pipe; S6, filling the composite wick bent high-temperature heat pipe with the internal working fluid of the heat pipe, and then performing a rough vacuum operation to maintain the internal pressure of the heat pipe within 10Pa; S7, heat and exhaust the composite liquid wick bent high temperature heat pipe, heat it at 250℃, 550℃ and 750℃ for a preset time respectively, and then perform vacuum operation again to maintain the internal pressure of the heat pipe at 10 -4 Pa, the heat pipe is sealed using laser welding technology to complete the production of the composite liquid-absorbing core curved high-temperature heat pipe.

2. The method for manufacturing a composite wick bent high-temperature heat pipe according to claim 1, characterized in that: The metal powder of the heat pipe additive manufacturing material is stainless steel metal powder, titanium alloy powder, copper alloy powder, nickel alloy powder or oxide dispersion strengthened alloy powder.

3. The method for manufacturing a composite wick curved high-temperature heat pipe according to claim 1, characterized in that: The types of the composite liquid absorbent core include a combination of a channel type and a sintered powder type, a combination of a channel type and a wire mesh type, a combination of a trunk type and a wire mesh type, or a combination of a trunk type and a sintered powder type.

4. The method for manufacturing a composite wick curved high-temperature heat pipe according to claim 3, characterized in that: The groove type is formed by additive manufacturing together with the heat pipe wall. The number of grooves is 20 to 100. The groove depth does not exceed half the thickness of the heat pipe wall. The width is determined by the outer diameter of the heat pipe and the number of grooves, and is 0.1mm to 0.5mm. The trunk type is formed by additive manufacturing together with the heat pipe wall, with a number of 1 to 6 trunks, and the cross-section of the trunks includes circular, elliptical, quadrilateral, and triangular shapes; The wire mesh type is woven from metal warp and weft threads attached to the channel, and is produced together with the channel type or trunk type by an additive method. The mesh number of the wire mesh is 100 to 800, and the number of layers is 1 to 5. The sintered powder type is produced by an additive method together with a channel type or a dry channel type, and has a thickness of 0.3 mm to 2 mm, and a sintered material powder particle size of 30 μm to 200 μm; The heat pipe has a length of 80cm to 400cm, an outer diameter of φ10mm to φ40mm, 1 to 4 bending sections, a length of 10cm to 100cm, a bending angle of 0° to 120°, and a bending radius of 50mm to 500mm.

5. The method for manufacturing a composite wick bent high-temperature heat pipe according to claim 1, characterized in that: The powder material pretreatment includes spraying adhesive and screening metal powder.

6. The method for manufacturing a composite wick curved high-temperature heat pipe according to claim 1, characterized in that: The outer shape of the curved heat pipe includes one or more of a straight shape, an L shape, a U shape, and an S shape.

7. The method for manufacturing a composite wick curved high-temperature heat pipe according to claim 1, characterized in that: The inert gas atmosphere protection environment is a nitrogen atmosphere environment, a helium atmosphere environment or an argon atmosphere environment.

8. The method for manufacturing a composite wick curved high-temperature heat pipe according to claim 1, characterized in that: The length of the local heat pipe assembly is 10cm to 120cm, the outer diameter of the assembly is φ10mm to φ40mm, the wall thickness is 0.5mm to 2mm, the bending angle is 0° to 120°, and the bending radius is 50mm to 500mm.

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