A large-aspect-ratio dry channel type sintered wick high-temperature heat pipe and a preparation method thereof

Abstract

The application provides a large-length-diameter ratio dry channel sintered wick high-temperature heat pipe and a preparation method thereof, and belongs to the technical field of high-temperature heat pipes.The high-temperature heat pipe comprises a pipe shell, an end cover, a porous wick, a wire mesh dry channel and a liquid metal working medium; the porous wick, the pipe shell and the wire mesh dry channel are integrally sintered and formed.The porous wick, the pipe shell and the wire mesh dry channel are integrally sintered and formed, so that the contact thermal resistance can be reduced, the porous wick has high capillary force and large heat exchange area, the wire mesh dry channel has high permeability, and the heat transfer efficiency and heat transfer distance of the high-temperature heat pipe can be significantly improved.When the preparation method is used to prepare the large-length-diameter ratio dry channel sintered wick high-temperature heat pipe, the intermediate core rod is easy to be demolded, no release agent or other impurities that pollute the wick are introduced, the problem of difficult demolding of the high-temperature heat pipe is solved, and the large-length-diameter ratio dry channel sintered wick high-temperature heat pipe can be used for standardized and batch production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature heat pipe, in particular to a large-length-diameter ratio dry channel sintered wick high-temperature heat pipe and a preparation method thereof. BACKGROUND

[0002] The high-temperature heat pipe takes liquid metal as a phase change working medium, has the advantages of high working temperature, large heat transfer capacity and high heat transfer efficiency, and has broad application prospects in the fields of nuclear energy system, hypersonic aircraft thermal protection, molten salt reactor energy conversion system, etc. The traditional high-temperature heat pipe wick is mainly of a wire mesh structure and a groove structure. Among them, the wire mesh structure is widely studied due to the advantages of simple preparation process and large permeability of the wire mesh wick. The preparation of sintered wick high-temperature heat pipe is rarely reported. On the one hand, it is difficult to integrate sintering of the large-length-diameter ratio high-temperature heat pipe due to the limitation of sintering equipment; on the other hand, there are problems such as difficulty in pulling out the core rod in the preparation process of the large-length-diameter ratio sintered wick, and the introduced release agent will pollute the liquid metal working medium with high purity. Therefore, it is of great significance to study a preparation method of a large-length-diameter ratio dry channel sintered wick high-temperature heat pipe. SUMMARY

[0003] The present application aims to provide a large-length-diameter ratio dry channel sintered wick high-temperature heat pipe and a preparation method thereof, so as to solve the problems of difficulty in integrated sintering of the large-length-diameter ratio high-temperature heat pipe and difficulty in pulling out the core rod in the prior art.

[0004] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0005] The present application provides a large-length-diameter ratio dry channel sintered wick high-temperature heat pipe, comprising a pipe shell, an end cover, a porous wick, a wire mesh dry channel and a liquid metal working medium; the porous wick, the pipe shell and the wire mesh dry channel are integrally sintered and formed.

[0006] Preferably, the end cover is located at both ends of the pipe shell; and the porous wick is attached to the inner wall of the pipe shell.

[0007] Preferably, the porosity of the porous wick is 40-80%.

[0008] Preferably, the pore size of the wire mesh in the wire mesh dry channel is 200-800 mesh, and the number of layers of the wire mesh is 2-4 layers.

[0009] Preferably, the wire mesh dry channel is located inside the porous wick.

[0010] The present application also provides a preparation method of the above-mentioned large-length-diameter ratio dry channel sintered wick high-temperature heat pipe, comprising the following steps:

[0011] (1) winding a wire mesh on a metal rod and fixing it to obtain a wire mesh dry channel mold;

[0012] (2) The magnetic sleeve is sleeved on the outer wall of the tube shell, and then the wire mesh dry channel mold is placed in the tube shell and adheres to the inner wall of the tube shell under the magnetic force;

[0013] (3) The core rod is placed in the tension spring to prepare the core rod mold, and then the core rod mold is placed in the center of the tube shell, the metal powder is filled into the gap between the tube shell and the tension spring, and then sintering is carried out;

[0014] (4) After sintering, the tension spring is pulled out, then the end covers are welded at both ends of the tube shell, and finally the liquid metal working medium is filled to obtain the large-length-diameter-ratio dry channel sintered wick high-temperature heat pipe.

[0015] Preferably, in step (1), the diameter of the metal rod is 0.5-3 mm.

[0016] Preferably, in step (2), the magnetic sleeve has a positioning hole for placing a positioning rod and a magnet embedding hole for placing a magnet; the magnet can magnetically attract the wire mesh dry channel mold to the inner wall of the tube shell, and the positions of the magnet and the wire mesh dry channel mold are one-to-one corresponding.

[0017] Preferably, in step (3), the bottom of the tension spring is plugged into a plug, the core rod mold is placed in the center of the tube shell, the top of the tube shell is plugged into the plug, and the plug is provided with a through hole.

[0018] Preferably, in step (4), the sintering temperature is 1150-1200℃, and the sintering time is 1-3h.

[0019] The beneficial effects of the present application are as follows:

[0020] (1) The large-length-diameter-ratio dry channel sintered wick high-temperature heat pipe has the advantages of small contact thermal resistance, adjustable pore size and porosity, large capillary force, large heat exchange area, etc., and the wire mesh dry channel has high permeability, so that the heat transfer efficiency and heat transfer distance of the high-temperature heat pipe can be significantly improved.

[0021] (2) The preparation method of the present application can easily pull out the core rod without introducing impurities such as release agent, solves the problem of difficult membrane pulling of the high-temperature heat pipe, and has the advantages of simple technical scheme, easy operation and high feasibility, which can be used for the standardized and batch production of the dry channel sintered wick high-temperature heat pipe. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1It is a profile schematic diagram of the large length-diameter ratio dry channel type sintered wick high temperature heat pipe of the application, wherein 1 is a pipe shell, 2 is a porous wick, 3 is a wire mesh dry channel, 4 is a left end cover, and 5 is a right end cover with a liquid filling port;

[0023] Figures 2 to 9 It is a preparation process schematic diagram of the large length-diameter ratio dry channel type sintered wick high temperature heat pipe of the application embodiment 1, wherein Figure 2 3-1 is a circular iron rod, and 3-2 is a wire mesh; Figure 3 1 is a stainless steel pipe shell, 6-1 is a magnetic sleeve, 6-2 is a stainless steel cylindrical positioning rod, and 6-3 is a cylindrical magnet; Figure 4 7-1 is an intermediate core rod, 7-2 is a compression spring, 8-1 is a stainless steel plug, 8-2 is a plug with a through hole, 8-3 is a through hole on the plug 8-2, and 8-4 is a plug; Figure 8 3 is a wire mesh dry channel formed after sintering of the circular iron rod 3-1 and the wire mesh 3-2; Figure 9 4 is an end cover, and 5 is an end cover with a liquid filling hole. The same reference signs in different drawings represent the same parts. DETAILED DESCRIPTION

[0024] The application provides a large length-diameter ratio dry channel type sintered wick high temperature heat pipe, which comprises a pipe shell, an end cover, a porous wick, a wire mesh dry channel and a liquid metal working medium; the porous wick, the pipe shell and the wire mesh dry channel are integrally sintered and formed.

[0025] In the application, the end cover is located at both ends of the pipe shell; and the porous wick is attached to the inner wall of the pipe shell.

[0026] In the application, the porosity of the porous wick is 40-80%, preferably 50-70%, and further preferably 68%.

[0027] In the application, the pore size of the wire mesh in the wire mesh dry channel is 200-800 meshes, preferably 300-600 meshes, and further preferably 400-500 meshes; and the number of layers of the wire mesh is 2-4 layers, preferably 3 layers.

[0028] In the application, the wire mesh is preferably a wire mesh woven in a twill or plain weave manner.

[0029] In the application, the wire mesh dry channel is located inside the porous wick.

[0030] In the application, the material of the pipe shell, the end cover, the porous wick and the wire mesh in the wire mesh dry channel is preferably iron-based alloy, nickel-based high-temperature alloy, cobalt-based high-temperature alloy, molybdenum and its alloy, tungsten and its alloy, and niobium and its alloy.

[0031] The application also provides a preparation method of the large-length-to-diameter dry channel type sintered wick high-temperature heat pipe.

[0032] (1) winding the wire mesh on the metal rod and fixing the wire mesh to obtain a wire mesh dry channel mold;

[0033] (2) spacing the magnetic attraction sleeve into the outer wall of the pipe shell, and then placing the wire mesh dry channel mold in the pipe shell, and under the action of the magnetic force, the wire mesh dry channel mold is attached to the inner wall of the pipe shell;

[0034] (3) placing the core rod in the tension spring to obtain a core rod mold, and then placing the core rod mold in the center of the pipe shell, and then loading the metal powder into the gap between the pipe shell and the tension spring, and then sintering;

[0035] (4) after sintering, pulling out the tension spring, then welding end covers at both ends of the pipe shell, and finally filling the liquid metal working medium to obtain the large-length-to-diameter dry channel type sintered wick high-temperature heat pipe.

[0036] In the application, in the step (1), the diameter of the metal rod is 0.5-3 mm, preferably 1-2 mm. The cross-sectional shape of the metal rod is preferably circular or crescent.

[0037] In the application, in the step (1), the wire mesh is wound on the metal rod, and preferably the bottom of the wire mesh is folded and closed.

[0038] In the application, in the step (2), the magnetic attraction sleeve has a positioning hole and a magnet embedding hole, wherein the positioning hole is used for placing a positioning rod, and the magnet embedding hole is used for placing a magnet; the magnet can magnetically attract the wire mesh dry channel mold to the inner wall of the pipe shell, and the positions of the magnet and the wire mesh dry channel mold are one-to-one corresponding.

[0039] In the application, the magnetic attraction sleeve is segmented and spaced into the outer wall of the pipe shell; the positioning rod penetrates through the positioning hole of the magnetic attraction sleeve; the number of the positioning holes is preferably 2-5, and further preferably 3-4; the number of the magnet embedding holes is determined according to the number of the wire mesh dry channels.

[0040] In the application, in the step (3), the bottom of the tension spring is plugged into a plug; the core rod mold is placed in the center of the pipe shell, the top of the pipe shell is plugged into the plug, and the plug is provided with a through hole. The through hole is used for loading the metal powder into the gap between the pipe shell and the tension spring.

[0041] In the present application, when the metal powder is filled into the gap between the tube shell and the tension spring, the metal powder is constantly vibrated during the filling process, and the particle size of the metal powder is preferably 100-200 mesh; when the metal powder is filled to a distance of 1 cm from the tube shell, the metal rod in step (1) and the plug at the top of the tube shell are removed, the excess wire mesh at the end is folded and sealed, and it is buried in the metal powder, then a small amount of metal powder is continuously filled to completely bury the wire mesh in the metal powder, and then the plug is inserted into the top of the tube shell to prevent the metal powder from leaking out.

[0042] In the present application, before sintering, the magnetic sleeve is preferably removed, and the core rod is removed, and then sintering is performed.

[0043] In the present application, in step (4), the sintering temperature is 1150-1200℃, preferably 1150℃, 1160℃, 1180℃, 1200℃, and the sintering time is 1-3h, preferably 1.5-2.5h, and further preferably 2h.

[0044] The technical solutions provided by the present application will be described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present application.

[0045] Example 1

[0046] A round iron rod 3-1 with a diameter of 1mm is selected, a 400 mesh wire mesh is cut to a certain length, and then it is wound on the round iron rod 3-1 with 3 layers, and then the bottom of the wire mesh is folded and sealed to prepare a wire mesh dry channel mold (as shown in Figure 2 The two ends of the round iron rod are higher than the two ends of the wire mesh, which facilitates the removal of the round iron rod, and the wire mesh is a wire mesh woven by plain weave with a pore size of 300 mesh.

[0047] Four magnetic sleeves 6-1 (the inner diameter of the magnetic sleeve 6-1 is 20.1mm) are sleeved on the outer wall of the stainless steel tube shell 1 (the outer diameter of the stainless steel tube shell 1 is 20mm, the wall thickness is 1mm, and the length is 1500mm), each magnetic sleeve has 3 positioning holes and 4 magnet embedding holes, 3 stainless steel cylindrical positioning rods 6-2 are inserted through the positioning holes of the four magnetic sleeves 6-1, and the cylindrical magnets 6-3 are placed in the magnet embedding holes of the magnetic sleeves 6-1 (as shown in Figure 3 and Figure 4 Then the wire mesh dry channel mold is placed in the stainless steel tube shell 1, and under the action of the magnetic force, the wire mesh dry channel mold is tightly adsorbed on the inner wall of the stainless steel tube shell 1, and the position of the wire mesh dry channel mold corresponds to the position of the magnet 6-3 (as shown in Figure 5 ).

[0048] The intermediate mandrel 7-1 (the diameter of the intermediate mandrel 7-1 is 13 mm) is placed in the compression spring 7-2 (the outer diameter of the compression spring 7-2 is 15 mm, the inner diameter is 13.2 mm, and the length is 1510 mm), and then it is placed in the center of the stainless steel tube shell 1. The stainless steel plug 8-1 is inserted into the bottom of the compression spring 7-2, and the outer diameter of the plug 8-1 is consistent with the inner diameter of the stainless steel tube shell 1. The plug 8-2 is inserted into the top of the stainless steel tube shell 1, and the plug 8-2 has a through hole 8-3. The outer diameter of the plug 8-2 is consistent with the inner diameter of the stainless steel tube shell 1. The stainless steel metal powder can be filled into the gap between the stainless steel tube shell 1 and the compression spring 7-2 through the through hole 8-3 on the plug 8-2. The stainless steel metal powder is vibrated and compacted during the filling process. The stainless steel metal powder has an irregular morphology, and the particle size is between 100-200 meshes. When the stainless steel metal powder is filled to 1 cm from the top end of the stainless steel tube shell 1, the circular iron rod 3-1 is removed, the plug 8-2 is removed, the excess wire mesh at the end is folded and sealed, and it is buried in the stainless steel metal powder. A small amount of stainless steel metal powder is continuously filled to completely bury the wire mesh in the stainless steel metal powder. The plug 8-4 is inserted into the top of the stainless steel tube shell 1 to prevent the stainless steel metal powder from leaking out. Finally, the magnetic sleeve 6-1 is removed, and the intermediate mandrel 7-1 is taken out (the above steps are shown in Figure 6 、 Figure 7 and Figure 8 ), and then it is placed in a sintering furnace. The temperature of the sintering furnace is increased to 1150℃, and sintering is performed at this temperature for 2h. After sintering is completed, the plugs 8-1 and 8-4 are removed, and finally the compression spring 7-2 is slowly pulled out.

[0049] Then the end cap 4 is welded to the upper end of the stainless steel tube shell 1, and the end cap 5 with a liquid filling port is welded to the lower end of the stainless steel tube shell 1. Vacuum is drawn through the end cap 5, protective argon gas is injected, liquid metal sodium working medium is injected, and vacuum is drawn again. To further remove the internal non-condensable gas, the heat pipe is heated to 650℃ while continuing to draw vacuum. Finally, the liquid filling port is cold welded and sealed, and the liquid filling port is sealed again by argon arc welding. A large aspect ratio dry type sintered wick high temperature heat pipe is prepared, in which the porosity of the porous wick is 68% (the above steps are shown in Figure 9 ).

[0050] Example 2

[0051] The difference from Example 1 is that the sintering temperature is 1200℃, the sintering time is 1h, and the other conditions are the same.

[0052] Example 3

[0053] The difference from Example 1 is that the sintering temperature is 1180℃, the sintering time is 2h, and the other conditions are the same.

[0054] From the above embodiment, the application provides a large-length-diameter-ratio dry channel sintered wick high-temperature heat pipe and a preparation method thereof. The high-temperature heat pipe comprises a pipe shell, an end cover, a porous wick, a wire mesh dry channel and a liquid metal working medium; the porous wick, the pipe shell and the wire mesh dry channel are integrally sintered and formed. The porous wick, the pipe shell and the wire mesh dry channel are integrally sintered and formed, which can reduce the contact thermal resistance, the porous wick has high capillary force and large heat exchange area, the wire mesh dry channel has high permeability, and the heat transfer efficiency and heat transfer distance of the high-temperature heat pipe can be significantly improved. When the large-length-diameter-ratio dry channel sintered wick high-temperature heat pipe is prepared by using the preparation method, the intermediate core rod is easy to be demolded, no impurities such as release agent which pollutes the wick are introduced, the problem of difficult demolding of the high-temperature heat pipe is solved, and the standardized and batch production of the dry channel wick high-temperature heat pipe can be realized.

[0055] The above only describes the preferred embodiments of the application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be considered as the protection scope of the application.

Claims

1. A method for preparing a high-aspect-ratio, high-temperature heat pipe with a sintered liquid-absorbing core, characterized in that: The steps include: (1) Wrapping the wire mesh around a metal rod and fixing it to make a wire mesh main channel mold; (2) Insert the magnetic sleeve into the outer wall of the shell at intervals, then place the wire mesh main channel mold into the shell and adhere it to the inner wall of the shell under the action of magnetic force; (3) placing a core rod in a tension spring to make a core rod mold, then placing the core rod mold in the center of the tube shell, filling the metal powder into the gap between the tube shell and the tension spring, and then sintering; (4) After sintering is completed, the tension spring is pulled out, and then the end caps are welded at both ends of the tube shell, and finally the liquid metal working medium is filled to obtain a high-temperature heat pipe with a large aspect ratio and a dry channel sintered liquid absorption core; In the step (2), the magnetic sleeve has a positioning hole and a magnet embedding hole, wherein the positioning hole is used to place the positioning rod, and the magnet embedding hole is used to place the magnet; the magnet can magnetically attract the wire mesh main channel mold to the inner wall of the tube shell, and the positions of the magnet and the wire mesh main channel mold correspond one to one; The large aspect ratio trunk sintered liquid wick high temperature heat pipe comprises a tube shell, an end cover, a porous liquid wick, a wire mesh trunk and a liquid metal working medium; the porous liquid wick, the tube shell and the wire mesh trunk are integrally sintered and formed.

2. The method for preparing a high-aspect-ratio main channel sintered liquid wick high-temperature heat pipe according to claim 1, characterized in that: The end covers are located at both ends of the tube shell; and the porous liquid-absorbing core is attached to the inner wall of the tube shell.

3. The method for preparing a high-aspect-ratio main channel sintered liquid wick high-temperature heat pipe according to claim 1 or 2, characterized in that: The porosity of the porous liquid-absorbing core is 40-80%.

4. The method for preparing a high-aspect-ratio main channel sintered liquid wick high-temperature heat pipe according to claim 3, characterized in that: The aperture of the wire mesh in the wire mesh main channel is 200-800 meshes, and the number of layers of the wire mesh is 2-4 layers.

5. The method for preparing a high-temperature heat pipe with a large aspect ratio, a main channel sintered liquid wick, according to claim 1, 2 or 4, characterized in that: The wire mesh trunk is located inside the porous liquid-absorbing core.

6. The method for preparing a high-aspect-ratio main channel sintered liquid wick high-temperature heat pipe according to claim 5, characterized in that: In the step (1), the diameter of the metal rod is 0.5-3 mm.

7. The method for preparing a high-aspect-ratio main channel sintered liquid wick high-temperature heat pipe according to claim 4 or 6, characterized in that: In the step (3), a plug is inserted into the bottom of the tension spring; the core rod mold is placed in the center of the tube shell, and a plug is inserted into the top of the tube shell, and a through hole is provided on the plug.

8. The method for preparing a high-aspect-ratio main channel sintered liquid wick high-temperature heat pipe according to claim 7, characterized in that: In the step (4), the sintering temperature is 1150-1200° C., and the sintering time is 1-3 hours.

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