A loop heat pipe with a combination of multiple materials

Abstract

The present application relates to a loop heat pipe of a multi-material combination, which is applied to the field of thermal management technology. The loop heat pipe comprises: a disc-shaped evaporator, a gas phase pipeline, a condensation pipeline and a liquid phase pipeline, which are connected by two-way joints to form a loop heat pipe; the disc-shaped evaporator comprises: an evaporator end cover, an evaporator shell and an evaporator buckle cover, which are all made of stainless steel; the disc-shaped evaporator is equipped with a capillary wick and a heat-absorbing sheet made of copper, which is connected to the evaporator buckle cover and fits the heat source; the evaporator shell is designed with a middle rib plate, and the cavity formed by the combination of the middle rib plate and the evaporator end cover is a liquid storage cavity. The present application can improve the heat exchange efficiency and realize long-distance heat transfer.

Description

Technical Field

[0001] The present application relates to the field of thermal management technology, and in particular to a loop heat pipe composed of multiple materials. Background Art

[0002] With the rapid development of the Internet and cloud computing in various fields, the demand for large-scale data computing has increased dramatically, and data centers are the carriers of large-scale data computing. However, with the substantial increase in the demand for data centers, the heat flux density during operation continues to increase, and energy consumption is becoming increasingly intense. The loop heat pipe technology adopts the principle of phase change heat transfer and does not require external power. It has the characteristics of low thermal resistance, low energy consumption, good isothermal performance, high heat dissipation efficiency, and long heat transfer distance. The evaporation section of the loop heat pipe needs to be installed inside the cabinet of the data center, and the condensation section is installed outside the data center. Therefore, higher requirements are placed on the heat transfer distance of the loop heat pipe.

[0003] In the related art, loop heat pipes are mostly manufactured using welding processes, so only a single material can be used. The use of materials with low thermal conductivity such as stainless steel results in poor heat transfer performance, and the use of materials with high thermal conductivity such as aluminum alloy and copper results in serious heat leakage in the liquid storage device, which easily leads to loop heat pipe failure. In addition, the transmission distance of existing loop heat pipes is relatively short. On the one hand, to achieve self-driven operation of the loop heat pipe, the capillary driving force provided by the capillary core must be greater than the sum of the resistances of all parts of the loop heat pipe. The gas phase pipeline and liquid phase pipeline of the long-distance loop heat pipe are relatively long, and the capillary suction force is difficult to overcome the pipeline pressure drop, which limits the transmission distance of the loop heat pipe; on the other hand, if the gas phase pipeline is long, it is easy to leak heat at the gas phase pipeline, and the working fluid has been liquefied before reaching the condensation end, which limits the circulation of the loop heat pipe. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a loop heat pipe with a multi-material combination.

[0005] The embodiment of the present application provides a loop heat pipe of a multi-material combination, comprising: a disc-shaped evaporator, a gas phase pipeline, a condensation pipeline and a liquid phase pipeline, wherein the disc-shaped evaporator, the gas phase pipeline, the condensation pipeline and the liquid phase pipeline are connected by a two-way joint to form a loop heat pipe; the length of the gas phase pipeline is greater than a preset length;

[0006] The disc-shaped evaporator comprises: an evaporator end cover, an evaporator shell and an evaporator buckle cover, wherein the evaporator end cover, the evaporator shell and the evaporator buckle cover are all made of stainless steel; a capillary wick and a copper heat-absorbing sheet are installed inside the disc-shaped evaporator, the heat-absorbing sheet is connected to the evaporator buckle cover, and the heat-absorbing sheet is attached to the heat source;

[0007] The evaporator shell is designed with a middle rib, and the cavity formed by the combination of the middle rib and the evaporator end cover is the liquid storage cavity.

[0008] Optionally, the condensation pipeline includes: multiple sections of condensation pipeline, and the multiple sections of condensation pipeline are connected by two-way joints.

[0009] Optionally, the evaporator end cover, the evaporator shell and the evaporator buckle cover are connected by tight threads;

[0010] The heat absorbing sheet and the evaporator buckle cover are connected by a stepped bayonet.

[0011] Optionally, the capillary core is assembled between the middle rib and the evaporator buckle cover by using an interference fit.

[0012] Optionally, a steam channel is engraved on the bottom of the capillary core, and the steam channel is in direct contact with the heat absorption sheet.

[0013] Optionally, the cavity formed by the capillary wick and the evaporator shell is a steam cavity; the steam cavity is on one side of the capillary wick, and a capillary wick liquid surface is provided on the other side of the capillary wick, and the capillary wick liquid surface is a surface of the liquid reservoir cavity.

[0014] Optionally, the capillary core is a novel nickel-based capillary core, which is made of nickel powder as a metal material, calcium chloride and polymethyl methacrylate (PMMA) as a mixed composite pore-forming agent, and is manufactured by a metal sintering method.

[0015] Optionally, the gas phase pipeline and the liquid phase pipeline are both made of stainless steel.

[0016] Optionally, the condensation pipeline is made of aluminum alloy.

[0017] Optionally, the gas phase pipeline, the liquid phase pipeline and the condensation pipeline adopt a pipe bending process.

[0018] Compared with the prior art, the technical solution provided by the embodiments of the present application has the following advantages:

[0019] The evaporator adopts a disc-shaped design, including: evaporator shell, evaporator buckle cover and evaporator end cover. The evaporator shell, evaporator buckle cover and evaporator end cover are all designed with stainless steel. Stainless steel has a low thermal conductivity, which effectively reduces heat leakage from the liquid reservoir and reduces temperature fluctuations in the evaporator. The copper heat-absorbing surface is directly bonded to the heat source, which can reduce thermal resistance and improve heat absorption efficiency. Combining stainless steel with copper can improve heat absorption efficiency while improving the stability of the loop heat pipe operation. A longer gas phase pipeline is helpful to prevent the working fluid from leaking heat to the environment before reaching the condenser, which can increase the heat transfer distance of the loop heat pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 A schematic diagram of the structure of a loop heat pipe in an embodiment of the present application;

[0023] Figure 2 A schematic diagram of the structure of a disc-shaped evaporator in an embodiment of the present application;

[0024] Figure 3 This is an exploded schematic diagram of a disc-shaped evaporator in an embodiment of the present application;

[0025] Figure 4 It is a front cross-sectional view of a disc-shaped evaporator in an embodiment of the present application;

[0026] Figure 5 It is a side cross-sectional view of a disc-shaped evaporator in an embodiment of the present application;

[0027] Figure 6 A schematic diagram of the structure of the evaporator shell in the embodiment of the present application;

[0028] Figure 7 A schematic diagram of the structure of the evaporator buckle cover in the embodiment of the present application;

[0029] Figure 8 This is an exploded schematic diagram of the condensation pipeline in the embodiment of the present application;

[0030] Fig. 9 This is a schematic diagram of the structure of the evaporator end cover in the embodiment of the present application;

[0031] Fig.10 A schematic diagram of the structure of the capillary core in the embodiment of the present application;

[0032] Fig.11 It is a schematic diagram of the bottom surface of the capillary core in the embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the scheme of the present application will be further described below. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only part of the embodiments of the present application, rather than all of the embodiments.

[0035] The loop heat pipe technology, due to its excellent heat dissipation efficiency, flexible and convenient installation characteristics, anti-gravity and energy-saving advantages, provides people with a new idea for radiator design using the phase change heat dissipation principle, and gets rid of the traditional heat dissipation method that relies on high-power motor-driven air cooling and liquid cooling. It has the advantages of high heat dissipation capacity, long transmission distance, excellent temperature control characteristics, etc., and has a very broad market prospect.

[0036] The loop heat pipe mainly includes the evaporation section, the condensation section, the gas phase pipeline and the liquid phase pipeline. Its working principle is: after the liquid phase working medium absorbs the heat from the heat source at the evaporation end, it vaporizes into the gas phase working medium on the surface of the capillary wick in the evaporation end. The gas phase working medium overflows from the gas phase pipeline to the condensation end, transfers the heat to the heat sink at the condensation end, and releases heat to liquefy into the liquid phase working medium. Finally, the supercooled liquid flows back to the evaporator through the liquid phase pipeline. The liquid reservoir is used to store the working medium and supply liquid to the capillary wick in the evaporator to prevent the capillary wick from drying out.

[0037] The embodiment of the present application provides a loop heat pipe with a multi-material combination, which improves the traditional loop heat pipe structure and designs the evaporator in a way that combines stainless steel and copper. While reducing thermal resistance and improving heat transfer efficiency, it also reduces heat leakage in the liquid reservoir, solving the defect of the traditional loop heat pipe evaporator being made of a single material. A two-way connector is used to connect the disc-shaped evaporator, gas phase pipeline, liquid phase pipeline and condenser pipeline, and different condensers can be replaced according to different heat dissipation scenarios. The gas phase pipeline and the liquid phase pipeline can be made of stainless steel, and the condenser pipeline can be made of aluminum alloy. Combining stainless steel and aluminum alloy and optimizing the structural design can reduce heat leakage in the gas phase pipeline, achieve long-distance transmission, and make up for the defect of the short heat transfer distance of the traditional loop heat pipe.

[0038] See also Figure 1 , Figure 1 This is a structural schematic diagram of a loop heat pipe in an embodiment of the present application, including: a disc-shaped evaporator 1, a gas phase pipeline 2, a condensation pipeline 3 and a liquid phase pipeline 4, and the disc-shaped evaporator 1, the gas phase pipeline 2, the condensation pipeline 3 and the liquid phase pipeline 4 are connected by a two-way joint to form a loop heat pipe. The two-way joint connection can be convenient for disassembly and assembly, and the loop heat pipe can be flexibly arranged. The length of the gas phase pipeline 2 is greater than the preset length, that is, the length of the gas phase pipeline 2 is longer, which is conducive to preventing the working fluid from leaking heat to the environment before reaching the condenser, and improving the heat transfer distance of the loop heat pipe.

[0039] See also Figure 2The disc-shaped evaporator 1 includes: an evaporator end cover 1-1, an evaporator shell 1-2 and an evaporator buckle cover 1-5. The evaporator end cover 1-1, the evaporator shell 1-2 and the evaporator buckle cover 1-5 are all made of stainless steel. The disc-shaped evaporator is equipped with a capillary wick and a copper heat-absorbing sheet. The heat-absorbing sheet is connected to the evaporator buckle cover, and the heat-absorbing sheet is bonded to the heat source. Copper has a high thermal conductivity. Direct bonding of the copper heat-absorbing sheet to the heat source can reduce thermal resistance and improve heat absorption efficiency. See Figure 3 The disc-shaped evaporator 1 is internally equipped with a capillary core 1-3 and a heat absorbing sheet 1-4 made of copper.

[0040] The evaporator shell is designed with a middle rib, and the cavity formed by the middle rib and the evaporator end cover is the liquid reservoir cavity. Figure 4 and Figure 5 The liquid storage chamber 1-6 is between the evaporator end cover 1-1 and the evaporator shell 1-2. Figure 6 The evaporator shell 1-2 is designed with a middle rib 1-2-1, an upper side tight thread 1-2-2, a lower side tight thread 1-2-3, a liquid medium inlet 1-2-4, a steam outlet 1-2-5 and a capillary wick liquid absorption cavity 1-2-6. Figure 7 The evaporator buckle cover 1-5 is designed with a buckle cover dense thread 1-5-1 and a buckle cover stepped bayonet 1-5-2. The middle rib between the capillary core 1-3 and the liquid reservoir cavity 1-6 can effectively reduce the heat leakage from the evaporator to the liquid reservoir cavity, reduce the occurrence of loop heat pipe failure, and improve the stability of the loop heat pipe operation.

[0041] Optionally, the condensing line 3 may include: multiple sections of condensing lines, which are connected by two-way joints. In this way, the condensing line can be flexibly disassembled, and condensing lines of different lengths can be assembled according to heat dissipation requirements, with flexible layout and convenient assembly and disassembly. Figure 8 The condensation line 3 includes: a first section condensation line 3-2 and a second section condensation line 3-4; the first section condensation line 3-2 and the second section condensation line 3-4 are connected by a two-way connector 3-3, the two-way connector 3-3 can be a 6mm two-way connector, and the two-way connector 3-1 and the two-way connector 3-5 can be 6mm to 1 / 4 inch two-way connectors.

[0042] Optionally, the evaporator end cover, the evaporator shell and the evaporator buckle cover are connected by tight threads, which are easy to assemble and have good airtightness. Fig. 9The evaporator end cover 1-1 is provided with an end cover thread 1-1-1 and a filling port 1-1-2, and the middle rib plate and the evaporator end cover 1-1 are combined to form a liquid storage cavity 1-6. The heat absorbing sheet and the evaporator buckle cover are connected by a stepped bayonet, so that the stainless steel and copper materials are combined, and the bottom copper heat absorbing sheet is directly attached to the heat source. The combination of stainless steel and copper improves the heat absorption efficiency while improving the stability of the loop heat pipe operation.

[0043] Optionally, the capillary core is assembled between the middle rib and the evaporator buckle cover with an interference fit. The bottom of the capillary core is engraved with a steam channel, which can increase the heat exchange specific surface area. The steam channel is in direct contact with the heat absorber, which can increase the nucleation rate of the working fluid in the steam channel and improve the heat transfer efficiency. The liquid reservoir cavity is located on the upper side of the evaporator, and the steam channel is located on the lower side of the evaporator, which can reduce the heat leakage from the evaporator to the liquid reservoir cavity and make the capillary core easier to infiltrate.

[0044] Optionally, the cavity formed by the capillary wick and the evaporator shell is a steam cavity, and the steam cavity is on one side of the capillary wick, so that the steam in the steam channel is collected to optimize the capillary path. The other side of the capillary wick is provided with a capillary wick absorption liquid surface, so that the working medium fully infiltrates the capillary wick, and the capillary wick absorption liquid surface is a surface of the liquid reservoir cavity.

[0045] See also Fig.10 and Fig.11 The capillary wick 1-3 is provided with a capillary wick liquid absorption surface 1-3-2 and a steam channel 1-3-3. The capillary wick 1-3 and the evaporator shell 1-2 form a steam chamber 1-3-1.

[0046] Optionally, the capillary core is a new nickel-based capillary core, which is made of nickel powder as a metal material, calcium chloride and polymethyl methacrylate PMMA as a mixed composite pore-forming agent, and a metal sintering method. The ratio of Ni:CaCl:PMMA can be 16:3:1, so that the capillary core produces more nano-scale voids, improves the porosity, increases the capillary suction area and heat exchange area, and reduces the weight of the capillary core.

[0047] Optionally, both the gas phase pipeline and the liquid phase pipeline are made of stainless steel. Stainless steel has a low thermal conductivity, which can effectively prevent the gas phase pipeline from leaking heat to the environment and prevent the working fluid from being liquefied before reaching the condenser.

[0048] Optionally, the condensing pipeline is made of aluminum alloy, which has high thermal conductivity and can achieve efficient heat exchange between the condensing end and the heat sink. For example, the condensing pipeline can be made of a seventh series aluminum alloy.

[0049] Optionally, the gas phase pipeline, the liquid phase pipeline and the condensation pipeline adopt a pipe bending process, which is easy to process.

[0050] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0051] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A loop heat pipe composed of multiple materials, characterized in that: include: A disc-shaped evaporator, a gas phase pipeline, a condensation pipeline and a liquid phase pipeline, wherein the disc-shaped evaporator, the gas phase pipeline, the condensation pipeline and the liquid phase pipeline are connected by two-way joints to form a loop heat pipe; the length of the gas phase pipeline is greater than a preset length; The disc-shaped evaporator comprises: an evaporator end cover, an evaporator shell and an evaporator buckle cover, wherein the evaporator end cover, the evaporator shell and the evaporator buckle cover are all made of stainless steel; a capillary wick and a copper heat-absorbing sheet are installed inside the disc-shaped evaporator, the heat-absorbing sheet is connected to the evaporator buckle cover, and the heat-absorbing sheet is attached to the heat source; The evaporator shell is designed with a middle rib, and the capillary wick is assembled between the middle rib and the evaporator buckle cover by interference fit; the cavity formed by the combination of the middle rib and the evaporator end cover is the liquid reservoir cavity; the cavity formed by the capillary wick and the evaporator shell is a steam cavity; the steam cavity is on one side of the capillary wick, and a capillary wick liquid absorption surface is provided on the other side of the capillary wick, and the capillary wick liquid absorption surface is a surface of the liquid reservoir cavity and is in a stepped shape.

2. The loop heat pipe according to claim 1, characterized in that: The condensation pipeline comprises: multiple sections of condensation pipeline, and the multiple sections of condensation pipeline are connected by two-way joints.

3. The loop heat pipe according to claim 1, characterized in that: The evaporator end cover, the evaporator shell and the evaporator buckle cover are connected by tight threads; The heat absorbing sheet and the evaporator buckle cover are connected by a stepped bayonet.

4. The loop heat pipe according to claim 1, characterized in that: A steam channel is engraved on the bottom of the capillary core, and the steam channel is in direct contact with the heat absorption sheet.

5. The loop heat pipe according to claim 1, characterized in that: The capillary core is a novel nickel-based capillary core, which is made of nickel powder as metal material, calcium chloride and polymethyl methacrylate (PMMA) as mixed composite pore-forming agents, and is manufactured by a metal sintering method.

6. The loop heat pipe according to claim 1, characterized in that: The gas phase pipeline and the liquid phase pipeline are both made of stainless steel.

7. The loop heat pipe according to claim 1, characterized in that: The condensation pipeline is made of aluminum alloy.

8. The loop heat pipe according to claim 1, characterized in that: The gas phase pipeline, the liquid phase pipeline and the condensation pipeline adopt a pipe bending process.

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