Multi-channel loop heat pipe and radiator

Abstract

The multi-channel loop heat pipe comprises a heat pipe main body and a heat pipe cover plate, and the heat pipe cover plate is arranged on the open side of a cavity of the heat pipe main body; the heat pipe body is provided with an evaporation cavity and a plurality of condensation cavities, the condensation cavities are evenly distributed on the peripheral side of the evaporation cavity, each condensation cavity is communicated with the evaporation cavity through a corresponding steam channel and a corresponding liquid channel so as to form a multi-circulation heat dissipation structure, and a liquid storage cavity is formed between each condensation cavity and each liquid channel. According to the novel loop heat pipe, the multiple condensation cavities share one evaporation cavity, the overall structure is compact, the occupied space is small, the heat dissipation effect can be improved by 3-4 times compared with a single loop, and the heat dissipation capacity is greatly improved; and the device can adapt to different orientations in a gravity field and an acceleration field, and can be applied to heat dissipation of a high-power-consumption computing power module and heat dissipation in the aerospace field.

Description

Technical Field

[0001] The present invention relates to the technical field of radiators, and more particularly to a multi-channel loop heat pipe and a radiator. Background Art

[0002] With the development of the Internet of Things, edge computing, and 5G applications, data AI has driven the global computing power into a period of rapid growth. As the TDP of the new generation of servers has been raised to a level close to the limit of air cooling, the thermal power consumption of domestically produced independent controllable chips is relatively large. For example, the thermal power consumption of the entire board of Huawei Kunpeng 9206U VPX module can reach 280W. The high heat flux density AI chips of GPU, NPU and other Xpu (when the board design power is higher than 300W) have high power consumption and high heat dissipation requirements. A server needs to be composed of multiple Xpu board modules, as well as power modules, switching modules, etc., resulting in a huge increase in the heat flux density of the entire server. At the same time, in actual applications, the server is required to be small in size, limited in space, and compact in structure, so a new thermal management design must be carried out.

[0003] At present, high-computing chips and servers generally use fan forced air cooling, ordinary heat pipes, ordinary heat pipes + fans and other cooling methods. ① Air cooling uses air as a medium, through intermediate materials such as thermal interface materials, heat spreaders (VC) or heat pipes, and heat is dissipated by heat sinks or fans and air convection. Under natural cooling, the power that a 6U VPX board module can dissipate is 50-60W; under forced air cooling, the maximum power of the board is 200-300W, which has reached the limit. ② Ordinary heat pipes are generally a common heat dissipation method, which is low-cost and has mature processing technology. Traditional loop heat pipes are generally composed of four parts: evaporator, condenser, gas pipeline and liquid pipeline. The evaporator and condenser are connected by steam pipeline and liquid pipeline to form a closed loop. When the evaporator is heated, the liquid working medium evaporates on the outer surface of the capillary core, and the generated steam flows out from the gas pipeline. Under the action of density difference, it enters the condenser and is condensed into liquid. The condensate flows back into the evaporator through the liquid pipeline under the drive of the capillary pressure generated by the capillary core to evaporate again. In this way, heat exchange and transportation are circulated. During the whole process, the capillary core in the evaporator is an important power source and core component of the entire system cycle.

[0004] However, traditional loop heat pipes still have some defects, and there are two main disadvantages: one is that the steam flow is obstructed; the other is "burning dry". The obstruction of steam flow generally occurs when the loop heat pipe is started. When the loop heat pipe is started, the evaporator is heated to generate steam, and at the same time, new liquid working fluid needs to be added from the liquid pipeline under the action of the capillary core suction force. However, when the steam flow is obstructed, the gas working fluid cannot flow out of the evaporator, but is pressed back into the capillary core. At this time, the phenomenon of steam "backflow" occurs. The backflow steam blocks the capillary structure and hinders the reflux of the liquid working fluid, resulting in the inability of the working fluid to circulate smoothly. In addition, if the operating conditions of the traditional loop heat pipe suddenly change during operation, such as a sudden increase in heating power, it will also cause the "backflow" phenomenon, causing the heat pipe to stop working. "Burn-out" usually occurs during operation. When the loop heat pipe is running, as the heating power increases, the insufficient suction force of the capillary wick or the system filling rate is too low, causing the liquid working fluid in the capillary wick to decrease and dry up. At this time, the "burn-out" phenomenon occurs, causing the temperature of the inner wall of the evaporator to rise sharply, and the traditional loop heat pipe cannot work normally or may even be damaged.

[0005] In addition, the traditional loop heat pipe is only a single loop, and its heat dissipation efficiency is not high. In addition, when the traditional loop heat pipe is used in scenarios where the gravity field and acceleration field change, the steam pipeline or liquid pipeline is in different orientations, and the steam and liquid in the pipe body are affected by gravity and cannot quickly enter the condenser and evaporator respectively, thereby affecting the heat dissipation efficiency, making the traditional single circulation pipeline not suitable for gravity fields and acceleration fields, such as in the aerospace field.

[0006] Therefore, how to provide a multi-channel loop heat pipe and radiator that not only has good heat dissipation effect but can also be used for heat dissipation of high-computing power chips and heat dissipation in the aerospace field, overcome the gravity field and acceleration field, and thereby improve the applicability of the heat pipe; and enable the capillary wick of the evaporator to have sufficient liquid reserve and supply, reduce the "burn-dry" phenomenon of the evaporator and ensure the smooth circulation of the working fluid is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0007] In view of this, the present invention provides a multi-channel loop heat pipe and radiator that not only has good heat dissipation effect, but can also be used for heat dissipation of high-computing power chips and heat dissipation in the aerospace field, overcome the gravity field and acceleration field, and thus improve the applicability of the heat pipe; and can ensure that the capillary wick of the evaporator has sufficient liquid reserve and supply, reduce the "burn-dry" phenomenon of the evaporator and ensure the smooth circulation of the working medium.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] A multi-channel loop heat pipe comprises: a heat pipe body and a heat pipe cover plate, wherein the heat pipe cover plate is arranged on an open side of a cavity of the heat pipe body;

[0010] The heat pipe body has an evaporation chamber and a plurality of condensation chambers, the plurality of condensation chambers are evenly distributed on the outer periphery of the evaporation chamber, and each of the condensation chambers is connected to the evaporation chamber through a corresponding steam channel and a liquid channel to form a multi-cycle heat dissipation structure.

[0011] Wherein, a liquid storage cavity is provided between each of the condensation cavities and each of the liquid channels.

[0012] It can be seen from the above technical scheme that compared with the prior art, the present invention discloses a multi-channel loop heat pipe, which adopts a new type of loop heat pipe in which multiple condensation chambers share one evaporation chamber. Not only is the overall structure compact and occupies a small space, but the heat dissipation effect can be increased by 3-4 times compared with a single loop, thereby greatly improving the heat dissipation capacity; in addition, the multiple condensation chambers are evenly and symmetrically arranged, and can adapt to different orientations in the gravity field and acceleration field, overcoming the defect that the traditional heat pipe adopts a single loop, so that the steam and liquid in the steam pipeline or the liquid pipeline are easily affected by gravity and cannot quickly enter the condensation chamber and the evaporation chamber respectively, thereby affecting the heat dissipation efficiency. Therefore, the multi-channel loop heat pipe can be used in the heat dissipation of high-computing power chips and the heat dissipation field in the aerospace field, and has a wide range of applications. In addition, the built-in liquid storage chamber ensures that the capillary core in the evaporation chamber has sufficient liquid reserves and supply, reduces the "burning dry" phenomenon in the evaporation chamber, ensures that the gas and liquid circulate normally along the predetermined path, and at the same time reduces the gas reflux or the presence of non-condensable gas in the evaporation chamber, prevents gas plugging in the liquid channel and hinders the liquid supply of the capillary core in the evaporation chamber, solves the problems of unstable startup, and the work adaptability problem under the condition of too high temperature when working at high temperature. At present, the invention has been successfully applied to high-computing power servers and has passed the high-temperature test (60°C) and is running stably and reliably.

[0013] Furthermore, a plurality of fins are provided in the evaporation chamber and the condensation chamber.

[0014] The beneficial effects of the above technical solution are: the fins can increase the heat exchange area during evaporation and condensation, increase the evaporation and condensation speed, and make the heat dissipation effect of the loop heat pipe better. In addition, the fins can increase the overlap area of ​​the heat pipe body and the heat pipe cover, which is helpful for welding the two, and has the purpose of less welding deformation and high yield rate.

[0015] Furthermore, the heat pipe body and the heat pipe cover plate are both flat plate structures.

[0016] The beneficial effects of adopting the above technical solution are: increasing the heat exchange area of ​​the evaporation chamber, the condensation chamber, the steam channel and the liquid channel, and improving the high heat absorption and high heat dissipation of the loop heat pipe.

[0017] Furthermore, the width of the condensation chamber is greater than the width of the steam channel and the liquid channel.

[0018] The beneficial effects of adopting the above technical solution are: increasing the heat exchange area of ​​the condensation chamber and improving the condensation capacity.

[0019] Furthermore, the liquid storage chamber is located at the end of the condensation chamber.

[0020] The beneficial effect of adopting the above technical solution is that after the steam is converted into liquid through the condensation chamber, it is continuously accumulated and buffered in the liquid storage chamber, ensuring that the capillary wick in the evaporation chamber has sufficient liquid supply, avoiding the "burning dry" phenomenon in the evaporation chamber, which in turn causes the temperature of the inner wall of the evaporator to rise sharply, and the traditional loop heat pipe cannot work normally or even is damaged.

[0021] The present invention provides a radiator, comprising a radiator body and the multi-channel loop heat pipe, wherein the heat pipe body and the radiator body are fixed together by welding or bonding with thermal conductive silicone to ensure full contact between the multi-channel loop heat pipe and the radiator body, thereby increasing the efficient heat transfer effect between the two.

[0022] Furthermore, the material of the radiator body is an oxidized aluminum alloy, and the material of the heat pipe body is a copper material that is electroplated with nickel and tin, and the two are welded at low temperature.

[0023] The beneficial effect of adopting the above technical solution is that through the above treatment, the heat sink body and the heat pipe body with different melting points can be welded, and the problem of galvanic corrosion easily caused by the potential difference caused by direct contact between the two can be effectively avoided.

[0024] Furthermore, the radiator body is provided with a pull-out aid and a wedge-shaped locking strip.

[0025] The high-efficiency multi-channel loop heat pipe of the present invention solves the technical problems of high heat flux density, limited space, and high thermal power consumption in high-computing power servers in the era of intelligent computing. It can also be used in high heat flux density AI chips such as GPU, NPU and other Xpu (when the board design power is higher than 300W). It has broad market prospects and huge potential for economic benefits. At the same time, multiple condensation chambers are symmetrically designed, which can adapt to different orientations in the gravity field or acceleration field, and can also be used in the aerospace field. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention 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, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0027] Figure 1A schematic structural diagram of a multi-channel loop heat pipe provided by the present invention.

[0028] Figure 2 Schematic diagram of the structure of the heat pipe body.

[0029] Figure 3 This is a schematic diagram of a multi-channel loop heat pipe installed on a radiator body.

[0030] Figure 4 It is a schematic diagram of the structure of the explosion of the multi-channel loop heat pipe and the radiator body.

[0031] Figure 5 This is a schematic diagram of a radiator body provided with a pull-out aid and a wedge-shaped locking strip.

[0032] Figure 6 This is a schematic diagram of the radiator assembly from the first perspective.

[0033] Figure 7 This is a schematic diagram of the radiator assembly from the second perspective. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0035] like Figure 1-Figure 2 As shown, the embodiment of the present invention discloses a multi-channel loop heat pipe, comprising: a heat pipe body 1 and a heat pipe cover plate 2, wherein the heat pipe cover plate 2 is arranged on the open side of the cavity of the heat pipe body 1;

[0036] The heat pipe body 1 has an evaporation chamber 11 and a plurality of condensation chambers 12. The plurality of condensation chambers 12 are evenly distributed on the outer periphery of the evaporation chamber 11. Each condensation chamber 12 is connected to the evaporation chamber 11 through a corresponding steam channel 13 and a liquid channel 14 to form a multi-circulation heat dissipation structure.

[0037] A liquid storage chamber 15 is provided between each condensation chamber 12 and each liquid channel 14 .

[0038] A plurality of fins 16 are disposed in the evaporation chamber 11 and the condensation chamber 12 .

[0039] The heat pipe body 1 and the heat pipe cover plate 2 are both flat plate structures.

[0040] The width of the condensation chamber 12 is greater than the widths of the steam channel 13 and the liquid channel 14 .

[0041] The liquid storage chamber 15 is located at the end of the condensation chamber 12 .

[0042] like Figure 3-Figure 5 As shown, a heat sink of the present invention comprises a heat sink body 3 and a multi-channel loop heat pipe, and the heat pipe body 1 and the heat sink body 3 are fixed by welding or bonding with thermal conductive silicone.

[0043] The radiator body 3 is made of oxidized aluminum alloy, and the heat pipe body 1 is made of copper plated with nickel and tin. The edges of the two are welded at low temperature, and finally the holes for degassing, pressure reduction, and filling of working fluid are processed. After the vacuum is evacuated and the working fluid is filled, the glue is sealed and inspected.

[0044] The heat sink body 3 calculates the surface area of ​​the heat sink fins according to the temperature difference between the heat sink fins entering and exiting the heat sink fins, the convection heat transfer coefficient, the ventilation volume, the specific heat of the air, and the total heat generated by the chip, thereby ensuring that the heat generated by each thermal power device in the module can be discharged to the heat sink in a timely and reliable manner under forced air cooling. In addition, the heat sink body 3 is provided with an ejector 4 and a wedge-shaped locking strip 5.

[0045] The working principle of the multi-channel loop heat pipe of the present invention is: after the cooling medium is heated and evaporated into gas in the evaporation chamber, under the action of the capillary wick, the cooling medium flows to the condensation chamber through the steam channel in the form of vapor. After being cooled, the cooling medium becomes liquid and flows to the liquid storage chamber, and passes through the liquid channel to the evaporation chamber in the form of liquid, completing a cycle. The cooling medium can circulate repeatedly in each channel loop heat pipe, thereby achieving an efficient heat dissipation and cooling effect.

[0046] The multi-channel loop heat pipe of the present invention can adopt a four-channel loop heat pipe that is symmetrical in top and bottom and left and right. It is mainly used for heat dissipation of high-power computing power modules. It is mainly composed of a computing power module radiator body and a four-channel loop heat pipe. The working principle is that the four-channel loop heat pipe absorbs the heat generated by the thermal power device in the computing power module and quickly conducts it to the module radiator body. The heat can be dissipated to the heat sink through the forced fan of the module installation box or penetrating liquid cooling and other heat dissipation methods, thereby ensuring that the thermal power devices in the computing power module can work stably and reliably.

[0047] In addition, the four condensing chambers of the present invention share one evaporation chamber and present a left-right symmetrical and up-down symmetrical heat dissipation structure. This innovation not only expands the evaporator area and increases the number of circuits of the heat dissipation capillary core (4), but also makes the overall structure more compact. The heat dissipation effect is increased by 3 to 4 times compared with a single loop. It can adapt to different orientations in the gravity field and acceleration field, overcome the gravity influence of steam in a single orientation, and can be used in the aerospace field.

[0048] At the same time, a liquid storage chamber is designed in the condensing chamber of each loop to store liquid, ensuring sufficient liquid reserve and supply to the capillary wick in the evaporation chamber, ensuring that the vapor and liquid flow along the predetermined path, and at the same time can reduce the gas reflux or the presence of non-condensable gas in the evaporation chamber, prevent gas plugging in the liquid channel from hindering the liquid supply to the capillary wick of the evaporation chamber, and solve problems such as unstable startup and work adaptability problems under high temperature conditions during high-temperature operation.

[0049] The present invention provides capillary cores in the evaporation chamber, the condensation chamber, the steam channel and the liquid channel, thereby increasing the circulation capacity of the multi-channel loop.

[0050] Selection and proportioning of the cooling medium of the present invention: First, a suitable medium should be selected according to the operating temperature range of the loop heat pipe radiator. Within the operating temperature range, the medium must be able to exist in a gas-liquid two-phase state, that is, the lowest operating temperature of the loop heat pipe radiator should be higher than the solidification point of the medium, and the highest operating temperature should be lower than the critical temperature of the medium. Otherwise, the medium will freeze in the loop or fail to undergo a phase change, and the loop heat pipe radiator will not be able to operate normally. The present invention innovates the traditional ammonia medium. According to the melting point of ammonia at room temperature and pressure is -77.75°C, the boiling point is -33.5°C, and some coolant needs to be appropriately added (such as No. 65 coolant condensation, the solidification point of No. 65 coolant is -65°C). The cooling medium of the present invention uses ammonia and No. 65 coolant in a ratio of 55:45, ensuring that the new proportion of the coolant does not solidify at -65°C, and can be vaporized at about 55 degrees, thereby improving the heat absorption capacity and heat dissipation speed of the cooling medium, and achieving stable, reliable, and efficient heat conduction results.

[0051] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0052] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-channel loop heat pipe, characterized in that: include: A heat pipe body (1) and a heat pipe cover plate (2), wherein the heat pipe cover plate (2) is arranged on the open side of the cavity of the heat pipe body (1); The heat pipe body (1) is provided with an evaporation chamber (11) and a plurality of condensation chambers (12), the plurality of condensation chambers (12) being evenly distributed on the outer periphery of the evaporation chamber (11), and each of the condensation chambers (12) being connected to the evaporation chamber (11) via a corresponding steam channel (13) and a liquid channel (14), so as to form a multi-circulation heat dissipation structure. Wherein, a liquid storage chamber (15) is provided between each of the condensation chambers (12) and each of the liquid channels (14).

2. A multi-channel loop heat pipe according to claim 1, characterized in that: A plurality of fins (16) are provided in the evaporation chamber (11) and the condensation chamber (12).

3. A multi-channel loop heat pipe according to claim 1, characterized in that: The heat pipe body (1) and the heat pipe cover plate (2) are both flat plate structures.

4. The multi-channel loop heat pipe according to claim 1, characterized in that: The width of the condensation chamber (12) is greater than the widths of the steam channel (13) and the liquid channel (14).

5. The multi-channel loop heat pipe according to claim 1, characterized in that: The liquid storage chamber (15) is located at the end of the condensation chamber (12).

6. A radiator, characterized in that: It comprises a radiator body (3) and the multi-channel loop heat pipe according to any one of claims 1 to 5, wherein the heat pipe body (1) and the radiator body (3) are fixed by welding or bonding with thermal conductive silicone.

7. A radiator according to claim 6, characterized in that: The material of the radiator body (3) is an oxidized aluminum alloy, and the material of the heat pipe body (1) is a copper material that has been electroplated with nickel and tin, and the two are welded at low temperature.

8. The radiator according to claim 6, characterized in that: The radiator body (3) is provided with a pull-out aid (4) and a wedge-shaped locking strip (5).

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