External pipeline loop heat pipe

Abstract

The invention provides an external pipeline loop heat pipe which comprises an evaporator and a cover plate, the cover plate and the evaporator are packaged together, the cover plate is provided with an inlet and an outlet of the evaporator, and the external pipeline loop heat pipe is characterized by further comprising an external pipeline, an external pipeline is connected to a bonding body of the silica gel cover plate and the evaporator through a connector to form the loop heat pipe. The loop pipeline is a PTFE pipeline which is different from the design of all silicon crystals of a traditional silicon-based loop heat pipe and can be bent, formed and the like, design and arrangement of the loop pipeline are facilitated, and adaptability to different devices is improved.

Description

Technical Field

[0001] The present invention relates to the field of heat exchange, and particularly to a loop heat pipe. Background Art

[0002] Heat pipe technology was invented in 1963 by George Grover of Los Alamos, USA, National Laboratory a heat transfer device called a "heat pipe", which makes full use of the principle of heat conduction and the rapid heat transfer property of the phase change medium. Through the heat pipe, the heat of the heat-generating object is quickly transferred outside the heat source, and its heat conduction ability exceeds that of any known metal. Component Heat pipe technology utilizes the heat transfer theory and the rapid heat transfer property of the phase change medium to quickly transfer the heat of the heating source outside the heat source through the heat pipe, and its heat conduction ability exceeds that of any known metal. Therefore, since the advent of heat pipe technology, it has become a research hotspot among many scholars at home and abroad in recent decades.

[0003] Heat pipe technology was previously widely used in industries such as aerospace and military. Since it was introduced into the radiator manufacturing industry, it has changed people's traditional radiator design ideas, getting rid of the single heat dissipation mode that solely relies on high-air volume motors to obtain better heat dissipation effects. Using heat pipe technology enables radiators to achieve satisfactory heat exchange effects, opening up a new world in the heat dissipation industry. Currently, heat pipes are widely used in various heat exchange devices, including the nuclear power field and the computer field, such as the waste heat utilization of nuclear power.

[0004] A loop heat pipe is an expansion of traditional heat pipe technology and is an efficient two-phase heat transfer device. The evaporator and the condenser are connected into a loop through the vapor pipeline and the liquid pipeline, and only the capillary force provided by the capillary wick is used to drive the circulation of the working fluid inside the pipe, without additional energy consumption, and the heat is transferred by the phase change of the working fluid. The structural characteristics of the loop heat pipe are: the vapor pipeline and the liquid pipeline are separated, and the evaporator and the compensator are integrated. Due to the compact structure, the gas-liquid carrying resistance is small, the start-up is fast and flexible, and it has good heat transfer ability, convenient installation, long-distance heat transfer, etc., and is widely used in many fields such as military, aerospace, and electronic equipment.

[0005] A loop heat pipe is a thermal management technology gradually developed based on the separated heat pipe technology, including an evaporator, a condenser, and vapor and liquid pipelines. The evaporator of the loop heat pipe includes a compensation chamber and a vapor chamber. The compensation chamber and the vapor chamber are connected by a capillary wick, and the capillary force provided by the capillary wick is used to drive the circulation of the working fluid. Compared with traditional heat pipes, the more reasonable capillary structure arrangement and design in the LHP and the separated gas-liquid pipelines greatly improve its heat transfer distance and system reliability, reduce the circulation resistance of the working fluid inside the system and the volume size of the system, and can realize the thermal management work in complex spaces.

[0006] Current heat pipes generally use silicon as the substrate, and the internal structure of the heat pipe is etched on the silicon substrate. The etching process is complex. For each manufactured silicon-based ultra-thin heat pipe, high-precision and repetitive etching is required, resulting in a relatively high manufacturing cost, which brings great challenges to its popularization and commercial use. The present invention provides a new type of loop heat pipe with a simplified internal structure, which can reduce the complexity of high-precision processing and etching of silicon-based materials. Therefore, the manufacturing cost of silicon-based ultra-thin loop heat pipes is greatly reduced. At the same time, the new heat pipe can be directly bonded to the heat dissipation source and can be used for heat dissipation in narrow spaces. Moreover, the working medium in the new heat pipe can be directly in contact with the outside of the device through an external pipeline, having a high heat transfer efficiency. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies. The present invention provides a low-cost, small-sized and highly efficient external pipeline loop heat pipe system to promote the popularization and commercial application of heat dissipation for heat sources. To achieve the above object, the technical solution of the present invention is as follows:

[0008] An external pipeline loop heat pipe, the loop heat pipe includes an evaporator and a cover plate. The cover plate and the evaporator are encapsulated together. An inlet and an outlet of the evaporator are provided on the cover plate. It is characterized in that it further includes an external pipeline, and the external pipeline is connected to the bonded body of the silicone cover plate and the evaporator by a joint to form a loop heat pipe.

[0009] The external pipeline extends to the outside of the evaporator through a PTFE pipeline.

[0010] The external pipeline is not directly connected to the evaporator, but is connected to the evaporator through the cooperation of the silicone cover plate female joint and the Luer joint.

[0011] The external pipeline is designed as a flexible PTFE pipeline, and the position of the pipeline can be arranged as needed.

[0012] The external pipeline is partially composed of a Luer joint, a PTFE connecting pipe and a PTFE outer pipe. The various parts are encapsulated through interference fit to achieve the required sealing performance.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1) The loop pipeline selects a PTFE pipeline, which is different from the all-silicon crystal design of traditional silicon-based loop heat pipes. It can be bent, formed, etc., which is convenient for the design and layout of the loop pipeline and improves the adaptability to different devices.

[0015] 2) By using an external pipeline to replace the condenser and the accumulator in the original structure, the present invention can reduce the complexity of high-precision processing and etching of silicon-based materials. Therefore, the manufacturing cost of silicon-based loop heat pipes is greatly reduced.

[0016] 3) The present invention uses silicon crystal material as the raw material of the evaporator, which can achieve the etching of high-precision capillary microchannels, and the selection of silicon crystal material can realize the direct integration with the heat dissipation component.

[0017] 4) The internal structure of the evaporator of the present invention is made of PMMA material. When the input heat load of the evaporator is higher, with the characteristics of thermal expansion and contraction of the material, the higher the heat load, the smaller the gap of the microchannels of the evaporator, and the greater the capillary suction force generated. When the heat is lower, the gap gradually increases, forming the self-adaptive ability of the evaporator to the heat load.

[0018] 5) The evaporator in the present invention is similar in size to the evaporator in the original silicon-based ultra-thin loop heat pipe. Through multiple tests, the original-sized silicon-based ultra-thin loop heat pipe has a high heat dissipation capacity, and the present invention adds pipelines for external heat exchange, further enhancing its heat dissipation capacity, thus proving the heat dissipation effect of this new type of heat pipe. Description of the Drawings

[0019] Figure 1 is the exploded view and assembly view of the new loop heat pipe with external pipelines of the present invention after being combined with the chip;

[0020] Figure 2 is the schematic diagram of the cooperation between the silica gel cover plate of the evaporator of the present invention and the chip

[0021] Figure 3 is the schematic diagram of the silica gel cover plate of the new loop heat pipe with external pipelines of the present invention;

[0022] Figure 4 is the cross-sectional view of the through hole of the silica gel cover plate of the new loop heat pipe with external pipelines of the present invention;

[0023] Figure 5 is the overall schematic diagram of the evaporator of the new loop heat pipe with external pipelines of the present invention;

[0024] Figure 6 is the partial schematic diagram of the evaporator of the new loop heat pipe with external pipelines of the present invention;

[0025] Figure 7 is the schematic diagram of the connection between the Luer connector and the pipeline of the new loop heat pipe with external pipelines of the present invention;

[0026] The reference numerals are as follows: 1 evaporator, 2 silica gel cover plate, 3 Luer connector, 4 PTFE connecting pipe, 5 PTFE external connecting pipe, 6 chip 2-1 female connector, 2-2 evaporator inlet, 2-3 evaporator outlet, 1-1 liquid phase region, 1-2 gas phase region, 1-3 internal microchannels of the evaporation chamber Detailed Embodiments

[0027] The following will give a detailed description of the specific embodiments of the present invention with reference to the drawings.

[0028] The specific implementation method of the present invention will be further described below in conjunction with the accompanying drawings.

[0029] Figures 1-7 Disclosed is an external pipeline loop heat pipe applied to a chip. As Figure 1 shown, an external pipeline loop heat pipe includes an evaporator 1, a silica gel cover plate 2, and an external pipeline part 3-5. The evaporator 1 and the silica gel cover plate 2 are encapsulated together. The silica gel cover plate includes a female joint 2-1, an evaporator inlet 2-2, and an evaporator outlet 2-3. The evaporator includes an internal microchannel 1-3 in the evaporation chamber, a liquid phase region 1-1, and a gas phase region 1-2. The external pipeline includes a Luer joint 3, a PTFE connecting pipe 4, and a PTFE outer pipe 5. The external pipeline part not only plays the role of connecting the inlet and outlet of the evaporator, but also plays the role of the condensation chamber and the liquid storage chamber in the traditional ultra-thin silicon-based loop heat pipe.

[0030] The present invention uses silicon crystal material as the raw material of the evaporator, which can achieve the etching of high-precision capillary microchannels, and the selection of silicon crystal material can realize the direct integration with heat dissipation components, such as chips.

[0031] The present invention uses silica gel material for the cover plate, which has the same properties as the silicon crystal material of the evaporator, can be better encapsulated, and can achieve a better integration effect.

[0032] The loop pipeline of the present invention selects PTFE pipeline, which is different from the all-silicon crystal design of the traditional silicon-based loop heat pipe, can be bent, formed, etc., is convenient for the design and layout of the loop pipeline, and improves the adaptability to different devices.

[0033] As an improvement, the PTFE connecting pipe 4 and the PTFE outer pipe 5 are of an integrated structure and are integrally manufactured.

[0034] By using an external pipeline to replace the condenser and the liquid reservoir in the original structure, the present invention can reduce the complexity of high-precision processing and etching of silicon-based materials, and therefore, greatly reduce the manufacturing cost of the silicon-based loop heat pipe.

[0035] Preferably, the external pipeline 3 is designed as a flexible PTFE pipeline, and the position of the pipeline can be arranged as needed.

[0036] As an improvement, microchannels are etched inside the evaporator by an etching method. The internal microchannel structure of the evaporator of the present invention is filled with a capillary material made of PMMA. When the input heat load of the evaporator is higher, with the characteristics of thermal expansion and contraction of the material, the higher the heat load, the smaller the gap of the evaporator microchannel, and the greater the capillary suction force generated. When the heat is lower, the gap gradually increases, forming the self-adaptive ability of the evaporator to the heat load.

[0037] In the present invention, a microchannel made of silicon crystal material is combined with PMMA material. Compared with a single PMMA material, it can fully realize capillary action and at the same time produce good heat absorption and capillary effects.

[0038] As an improvement, from the liquid phase region 1-1 to the gas phase region 1-2, the mass percentage content of the PMMA material filled in the capillary material is getting higher and higher. Due to the increasing PMMA material, the capillary force gradually increases under the condition of high heat from the liquid phase region 1-1 to the gas phase region 1-2, enabling more liquid to be quickly drained to the gas phase region 1-2 for heat evaporation, thereby improving the evaporation efficiency.

[0039] As an improvement, from the liquid phase region 1-1 to the gas phase region 1-2, the increasing amplitude of the mass percentage content of the PMMA material filled in the capillary material gradually increases. Preferably, it is 100% close to the position of the liquid phase region 1-1. Due to the continuous increase in the increasing amplitude of the PMMA material, the increasing amplitude of the capillary force gradually becomes larger under the condition of high heat from the liquid phase region 1-1 to the gas phase region 1-2, enabling more liquid to be accelerated and drained to the gas phase region 1-2 for heat evaporation, thereby improving the evaporation efficiency. The above amplitude change is also obtained through a large number of numerical simulations and experiments, and it is not common knowledge in the art.

[0040] In the present invention, the evaporator is similar in size to the evaporator in the original silicon-based ultra-thin loop heat pipe. Through multiple tests, the original-sized silicon-based ultra-thin loop heat pipe has a high heat dissipation capacity, and the present invention adds pipelines for external heat exchange, further enhancing its heat dissipation capacity, thus proving the heat dissipation effect of this new type of heat pipe.

[0041] Preferably, the evaporator 1 is directly bonded to the silica gel cover plate 2, and the silica gel cover plate serves as the evaporator cover plate.

[0042] The external pipeline serves as a condenser and adopts a bent loop design, and is connected to the heat dissipation component through a heat conduction material, increasing the effective heat exchange area.

[0043] Preferably, the evaporator includes a microchannel 1-3, a liquid phase region 1-1, and a gas phase region 1-2. The microchannel is connected to the external pipeline through the liquid phase pipeline and the gas phase pipeline inlets and outlets.

[0044] Preferably, the external pipeline 3 is not directly connected to the evaporator 1, but is connected to the evaporator through the cooperation of the silica gel cover plate female joint 2-1 and the Luer joint 3.

[0045] Preferably, the silica gel cover plate 2 is provided with holes corresponding to the working medium inlets and outlets of the evaporator, and the inlets and outlets of the external pipeline are connected to the evaporator through the holes 2-2 and 2-3 of the silica gel cover plate.

[0046] Preferably, the holes 2-2 and 2-3 of the silica gel cover plate and the silica gel cover plate female joint 2-1 are concentric circles.

[0047] Preferably, the silicon-based microchannel 1-3 is a capillary structure. In the present invention, the silicon-based microchannel is provided on the silicon substrate. On the one hand, it realizes the integration with the chip. On the other hand, it enables the coolant to quickly return to the evaporation chamber for heat dissipation, improving the heat dissipation efficiency.

[0048] As Figure 6 shown, the internal microchannels of the external loop heat pipe evaporator adopt the form of a rectangular parallel microchannel array, with an overall size of 20mm×20mm, a microchannel width of 90μm, a depth of 180μm, and a septum width between channels of 90μm. Since the microchannel structure is made of PMMA material, when the input heat load of the evaporator is higher, with the characteristics of thermal expansion and contraction of the material, the higher the heat load, the smaller the gap of the evaporator microchannels, and the greater the capillary suction force generated. When the heating is lower, the gap gradually increases, forming the self-adaptive ability of the evaporator to the heat load.

[0049] As Figure 7 shown, the external pipeline part consists of a Luer joint 3, a PTFE connecting pipe 4, and a PTFE outer connecting pipe 5. The various parts are encapsulated through interference fit to achieve the required sealing performance.

[0050] As Figure 1 shown, the evaporator 1 and the silica gel cover plate 2 are in direct contact. 1 and 2 are combined by a pressing process. The evaporator and the silica gel cover plate are hermetically combined. The pressing of the two provides a sealed space inside the evaporator. The Luer joint 3 and the silica gel cover plate female joint 2-1 are mechanically fitted, thus forming a complete radiator structure.

[0051] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

[0052] Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope defined by the claims.

Claims

1. An externally connected pipeline loop heat pipe, the loop heat pipe comprising an evaporator and a cover plate, the cover plate and the evaporator being encapsulated together, and an inlet and an outlet of the evaporator being provided on the cover plate, characterized in that, It further includes an external pipeline, and the external pipeline is connected to the bonded body of the silica gel cover plate and the evaporator by a joint to form a loop heat pipe.

2. The loop heat pipe according to claim 1, wherein The external pipeline extends to the outside of the evaporator through a PTFE pipeline.

3. The loop heat pipe according to claim 1, characterized in that, The external pipeline is not directly connected to the evaporator, but is communicated with the evaporator through the cooperation of the female joint of the silica gel cover plate and the Luer joint.

4. The loop heat pipe according to claim 1, wherein The external pipeline is designed as a flexible PTFE pipeline, and the position of the pipeline can be arranged as needed.

5. The loop heat pipe according to claim 1, characterized in that, The external pipeline part is composed of a Luer joint, a PTFE connecting pipe and a PTFE outer connecting pipe, and the encapsulation is realized through interference fit between the parts to achieve the required sealing performance.

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