Cooling device

Abstract

The embodiment of the present invention discloses a cooling device including a housing with a cooling chamber therein, a foaming device, and a circulation device. The cooling chamber contains a cooling liquid for cooling a heat-generating object, a part of the structure of the foaming device is immersed in the cooling liquid and can generate bubbles that can rise in the cooling liquid until they are attached to the surface of the heat-generating object to be cooled, and the circulation device is connected to the housing and is used to collect the evaporated cooling liquid, condense it, and then transport it back into the cooling chamber. The foaming device is installed to generate a group of bubbles for flushing the surface of the heating element, and the bubbles can replace the evaporation core, accelerate the evaporation of the liquid near the heating element, and reduce the superheating degree of the surface of the heating element. In addition, the group of bubbles can assist the detachment of the evaporation core from the surface of the heating element, increase the upper limit of the heat exchange capacity, prevent or delay the occurrence of film boiling, and increase the critical heat flow density, thereby increasing the phase transition heat exchange cooling capacity of the equipment and meeting the high heat dissipation needs.

Description

[Technical field]

[0001] The present invention relates to the field of enhanced heat transfer technology, and in particular to cooling devices. [Background technology]

[0002] In fields such as chip cooling, communication equipment heat dissipation, battery heat management, and data center heat dissipation, the rapid development of high frequency, high speed and integrated circuit technology in electronic devices has led to the increasingly obvious problem of narrow physical dimensions and ever-increasing total power density. As a result, the heat flow density of electronic devices is also increasing one after another. The high temperatures caused by the high heat flow density not only affect the performance of electronic devices, but also cause the entire device to burn out in severe cases.

[0003] In the related art, the immersion type liquid evaporation phase transition cooling technology is used to cool the heat generating elements inside the electronic device, and a large amount of latent heat is absorbed in the liquid evaporation phase transition process, which has a high cooling capacity and is favorable for the heat transfer of high heat flow density in a small space. However, the related art requires further improvement of the cooling capacity of the immersion type liquid evaporation phase transition cooling technology, and the high heat dissipation capacity is somewhat insufficient. Summary of the Invention [Problem to be solved by the invention]

[0004] In order to solve the above problem, a cooling device that enhances the cooling heat exchange capacity is provided. [Means for solving the problem]

[0005] 1. A cooling device comprising: The cooling device includes a housing, a foaming device, and a circulation device, the inside of the housing has a sealable cooling chamber for storing a cooling liquid, and the heat-generating object can be placed in the cooling chamber containing the cooling liquid to be cooled; A part of the structure of the foaming device is immersed in the cooling liquid, and can generate bubbles in the cooling liquid, and can make the bubbles rise in the cooling liquid until they adhere to the surface of the heat generating object to be cooled; The circulation device is connected to the housing and is used to collect and condense the evaporated cooling liquid, and then transport it back into the cooling chamber.

[0006] In some embodiments of the cooling device, the foaming device includes an air pump for providing a non-condensable gas and a bubble generator connected to the air pump, the bubble generator being disposed within the cooling chamber and positioned below the position of the heat-generating object when cooled, so that the gas generated by the air pump can rise and impact the heat-generating object after being discharged through the bubble generator.

[0007] In some embodiments of the cooling device, the bubble generator includes a sintered metal or ceramic based air stone or a showerhead having a number of holes, and the bubble generator is capable of generating more than 5 bubbles per cubic millimeter.

[0008] In some embodiments of the cooling device, the cooling device further comprises a detection feedback device, the detection feedback device including a temperature detector for detecting the surface temperature of a heat-generating object, and a feedback controller signal-connected to the temperature detector, the feedback controller signal-connected to the foaming device and capable of controlling the number of foams generated by the foaming device based on the temperature detected by the temperature detector.

[0009] In some embodiments of the cooling device, the circulation device includes a steam outlet having one end connected to the cooling chamber, a gas-liquid separator, and a reflux inlet having one end connected to the cooling chamber, the steam outlet and the reflux inlet are both connected to the gas-liquid separator via a pipe, the reflux inlet is located above or below the liquid level of the cooling liquid in the cooling chamber, and a first check valve is provided between the gas-liquid separator and the reflux inlet.

[0010] In some embodiments of the cooling device, the pipe for communicating with the gas-liquid separator at the vapor outlet is further provided with a condensing member through which cooling water passes, and the condensing member is used to liquefy the cooling liquid after evaporation.

[0011] In some embodiments of the cooling device, the gas-liquid separator is further provided with a pressure regulating device for regulating the internal pressure thereof.

[0012] In some embodiments of the cooling system, the pressure regulating device includes a second check valve connected to the liquid / gas separator and a pressure regulator connected to the second check valve.

[0013] In some embodiments of the cooling device, water, an organic solvent or a mixed liquid is selected as the cooling liquid depending on the operating temperature of the heat generating object.

[0014] In some embodiments of the cooling device, a side wall of the housing is provided with an observation plate for observing the internal state of the housing, and the observation plate is made of transparent quartz, acrylic or PC material. Effect of the Invention

[0015] The practice of the embodiments of the present invention has the following beneficial effects. As can be seen from the above, by providing a foaming device capable of generating bubbles in the cooling liquid, the bubbles can be used to flush the surface of the heating element, and the bubbles can replace the vaporization core, accelerate the evaporation of the liquid near the heating element, and reduce the superheat of the surface of the heating element; in the operating condition of low heat flow density, the heating element can enter a pseudo-boiling phenomenon with a surface superheat degree less than zero; in the operating condition of high heat flow density, the bubbles can assist the vaporization core to detach from the heating element surface, increase the upper limit of the heat exchange capacity, prevent or delay the occurrence of film boiling, increase the critical heat flow density, and further increase the phase transition heat exchange cooling capacity of the equipment, so as to meet the high heat dissipation needs. In addition, the cooling device provided by the embodiment of the present invention has a simple structure, a more compact volume, and reduces the cost of filling the working liquid. In order to more clearly describe the embodiments of the present invention or the prior art, the following briefly introduces drawings necessary for describing the embodiments or the prior art. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can also obtain other drawings based on these drawings without creative efforts. [Brief description of the drawings]

[0016] [Figure 1] 1 is a structural schematic diagram showing a cooling device according to an embodiment of the present invention. [Diagram 2] 1 is a structural schematic diagram showing a housing of a cooling device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The following clearly and completely describes the invention in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention, obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are included in the protection scope of the present invention.

[0018] An embodiment of the present invention provides a cooling device for cooling a heat-generating object, particularly a cooling device used for cooling a heat-generating element of an electronic device. In one embodiment, referring to FIG. 1, the cooling device includes a housing 1, a foaming device 2, and a circulation device 3, where the inside of the housing 1 has a sealable cooling chamber 11 for containing a cooling liquid, and the broken line in the figure indicates the liquid level of the cooling liquid. The cooling chamber 11 needs to be sealed sufficiently to prevent liquid leakage and pressure leakage, and the heat-generating element can be placed in the chamber 11 containing the cooling liquid and cooled by utilizing the heat absorption by evaporation of the cooling liquid. Note that water, an organic solvent, or a mixed liquid can be selected as the cooling liquid, and in practical applications, a non-flammable liquid with an appropriate boiling point, such as FC-72 fluorinated liquid, can be selected as the cooling liquid according to the operating temperature of the heat-generating element.

[0019] In addition, the material for manufacturing the housing 1 can be selected according to the specific application, and generally, a metal material or a polymer plate is used to manufacture the housing 1. As shown in Fig. 2, in order to clearly observe the internal state of the housing 1, an observation plate 12 for observing the internal state of the housing 1 may be installed at an appropriate position on the side wall of the housing 1, and the observation plate 12 may be embedded in the side wall of the housing 1 or adhered to the side wall of the housing 1, and the observation plate 12 may be made of transparent quartz, acrylic, PC material, etc.

[0020] The foaming device 2 includes a foaming section, which can be disposed in a cooling chamber 11 having a cooling liquid, and can generate bubbles in the cooling liquid to impact on the surface of the heating element to be cooled (hereinafter, simply referred to as the "cooling surface"). This requires that the position of the foaming section in the cooling chamber 11 is below the heating element, so that the bubbles generated by the foaming section can adhere to the cooling surface while rising in the cooling liquid. In the embodiment of the present invention, the heating element needs to be immersed in the cooling liquid when cooled, and in order for the bubbles generated by the foaming section to easily detach from the cooling surface when they adhere to the cooling surface and take away the temperature of the cooling surface, the cooling surface of the heating element (the surface to which the bubbles adhere) needs to be inclined at a certain angle with respect to a plane perpendicular to the direction in which the bubbles rise, and this angle is 15° or more. In general, the housing 1 is disposed on a horizontal plane, and the rising direction of the bubbles in the cooling liquid is perpendicular to the horizontal plane, so it can be said that the cooling surface needs to be inclined at an angle of 15° or more with respect to the horizontal plane. By inclining the cooling surface at a certain angle, air bubbles on the cooling surface can easily roll along the cooling surface and be detached, thereby enabling heat to be dissipated normally.

[0021] The circulation device 3 is installed in the housing 1, and serves to recover and utilize the cooling liquid, so that the evaporated cooling liquid can be collected and condensed, and then transported back into the cooling chamber 11.

[0022] The cooling device according to the embodiment of the present invention can be applied to cooling devices in various fields such as chip cooling, communication device heat dissipation, battery heat management, and data center heat dissipation. In the embodiment of the present invention, the cooling of a heat generating element of an electronic device is taken as an example. In the related art, a cooling process is performed on a heat generating element by using an immersion type liquid evaporation phase transition cooling technology, that is, the heat generating element is immersed in a cooling liquid, and the heat of the heat generating element is taken away by the evaporation heat absorption of the cooling liquid. Since a large amount of latent heat is absorbed during the evaporation phase transition process, the cooling capacity is much higher than that of the liquid cooling plate or immersion type single-phase liquid cooling in the prior art, and is more advantageous for heat transfer of high heat flow density in a small space. Moreover, the heat generating element is in direct contact with the cooling liquid, and the thermal resistance is reduced by adding a thermal conductive material (e.g., a thermal conductive paste, a thermal conductive sheet) in the indirect cooling system. In the evaporation phase transition system, the cooling liquid realizes cooling heat exchange by the occurrence of pool boiling, and there is no need to generate extra work in a device such as a pump to circulate the cooling liquid in the immersion type single-phase liquid cooling system, thereby reducing the energy consumption of the system.

[0023] The main influencing factors that affect the evaporation efficiency of the cooling liquid in the evaporation phase change system are as follows: (1) Surface superheat of the heating element (i.e., the surface temperature is higher than the boiling point of the cooling liquid) If the surface of the heating element does not reach a certain degree of superheat, the vaporization core cannot be triggered to form on the surface. The vaporization core here refers to the bubbles generated when the cooling liquid near the heating element is heated by the heat in the heating element. The lower the surface superheat of the ideal heating element, the better, thus avoiding the temperature of the heating element from being too high. (2) Frequency of detachment of vapor cores and average particle size of detached bubbles The start of the formation of an evaporation core on the surface of the heating element and the detachment of the evaporation core from the surface of the heating element are the main methods of cooling using the boiling of the cooling liquid (abbreviated as "boiling phase transition cooling"). The higher the frequency of the detachment of the evaporation core, the smaller the average particle diameter of the detached bubbles will be, and the higher the number of effective evaporation cores formed and the phase interface density (i.e., the contact area between the evaporation core and the surface of the heating element) will be, which will increase the heat exchange efficiency of the evaporation phase transition, and more heat will be removed from the heating element, resulting in a better cooling effect. (3) Critical heat flow density When the surface temperature of the heating element is too high and exceeds the critical heat flow density, the boiling mode will change, and a continuous gas film will form on the surface of the heating element, causing film boiling, which will hinder the heat exchange between the surface of the heating element and the liquid, causing the temperature of the heating element to increase rapidly, and the higher the critical heat flow density, the more favorable it is for boiling phase transition cooling. The key to developing the next generation of boiling phase transition cooling technology is how to rapidly generate a vaporization core to trigger boiling when the surface of the heating element is at a low superheat, increase the frequency of vaporization core detachment, and reduce the average particle size of the detached bubbles, so as to increase the effective vaporization core and phase interface density, increase the critical heat flow density, and prevent the occurrence of film boiling. The existing methods for promoting the generation of vaporization cores, increasing phase interface density, and preventing film boiling are electrolysis, surface modification, etc., and their disadvantages are poor reinforcement effect and continuity, complex structure, and high cost, making it difficult to commercialize on a large scale.

[0024] Compared with the conventional phase-change liquid cooling, the cooling device according to the embodiment of the present invention is provided with a foaming device 2 capable of generating bubbles, and the bubbles can be used to flush the surface of the heating element, and the bubbles can replace the vaporization core, so that the effective vaporization core and the working density of the phase interface of the cooling surface are greatly increased, the vaporization speed of the cooling liquid is greatly accelerated, and the heat exchange efficiency is increased. Specifically, when the heating element is operated with low power and the surface temperature is lower than the boiling point of the cooling liquid, the bubbles generated by the foaming device 2 impact the surface of the heating element to be cooled, and then the working liquid near the surface of the heating element enters a pseudo-boiling state, replacing the vaporization core generated when the cooling liquid boils. After the bubbles attach to the surface of the heating element, the liquid in the vicinity thereof vaporizes to absorb a large amount of heat in the heating element, and the vapor generated after the vaporization is stored in the bubbles, which accelerates the evaporation of the cooling liquid near the heating element, and improves the phase-change heat exchange cooling capacity, and the bubbles can detach from the heating element along the surface of the heating element and take away the heat of the heating element, thereby reducing the surface superheat required for boiling to begin.

[0025] When the heating element is operated at high power and the surface temperature is higher than the boiling point of the cooling liquid, the cooling liquid will generate a vapor core on the surface of the heating element due to the high temperature of the heating element, and the bubbles generated by the foaming device 2 will flash the surface of the heating element, merge with the vapor core due to the cooling liquid being higher than the boiling point on the surface of the heating element, and then detach from the cooling surface, which further assists the vapor core to detach from the surface of the heating element, and increases the frequency of the vapor core detachment. The assistance of the bubbles advances the timing of the vapor core detachment from the heating element, reducing the average particle size at the time of detachment, increasing the effective vapor core and phase interface density, thereby preventing or delaying the occurrence of film boiling, increasing the critical heat flow density, accelerating the evaporation of the liquid near the heating element, and the latent heat of vaporization absorbs a large amount of heat, reducing the surface temperature of the heating element, and meeting the high heat dissipation needs.

[0026] As can be seen from the above, by providing a foaming device 2 capable of generating bubbles in the cooling liquid, the bubbles can be used to flush the surface of the heating element, and the bubbles can replace the vaporization core, accelerate the evaporation of the liquid near the heating element, and reduce the superheat of the surface of the heating element. In the operating condition of low heat flow density, the heating element can enter a pseudo-boiling phenomenon in which the surface superheat is less than zero. In the operating condition of high heat flow density, the bubbles can assist the vaporization core to detach from the surface of the heating element, increase the upper limit of the heat exchange capacity, prevent or delay the occurrence of film boiling, and increase the critical heat flow density, so as to improve the phase transition heat exchange cooling capacity of the equipment and meet the high heat dissipation needs. In addition, the cooling device provided by the embodiment of the present invention has a simple structure, a more compact volume, reduces the filling of the working liquid, and reduces costs.

[0027] In one specific embodiment, referring to FIG. 1, the foaming device 2 includes an air pump 21 and a bubble generator 22 connected to the air pump 21. The air pump 21 is connected to the bubble generator 22 through an air supply pipe to supply gas to the bubble generator 22, and the bubble generator 22 is a foaming part of the foaming device 2 that can discharge gas. The gas provided by the air pump 21 is a non-condensable gas. For example, the air pump 21 can provide a non-condensable gas such as air, nitrogen gas or argon gas, and the flow rate of the gas can be controlled by an air valve inside the air pump 21, or by providing a flow rate control valve in the air supply pipe. The bubble generator 22 is provided in the cooling chamber 11, and is located below the position of the heat-generating object when it is cooled, so that the gas generated by the air pump 21 can rise and impact on the heat-generating object after being discharged through the bubble generator 22. The bubble generator 22 may be located directly below the heat-generating object or at a certain angle, as long as the generated bubbles can reach the surface of the heat-generating object.

[0028] The bubble generator 22 is an air stone made of sintered metal or ceramics, or a shower head with a few holes. Regardless of whether it is an air stone or a shower head, the holes for discharging air are all of a pore structure, and the pore diameter of these pore structures is 1 to 50 μm. By controlling the exhaust flow rate of the air pump 21, the pore diameter of the bubbles can be controlled so that the particle diameter when contacting the cooling surface of the heating element is 0.1 to 200 μm, and the density of the bubbles can be controlled so that 5 or more bubbles are generated per cubic millimeter. By providing a pore diameter of micropores, a large number of microbubbles can be generated in the cooling liquid, the frequency of detachment of the vaporization core can be increased, and the average particle diameter of the detached bubbles can be reduced, the effective phase interface density can be increased, and the critical heat flow density can be increased, thereby preventing or delaying the occurrence of film boiling.

[0029] In one embodiment, referring to FIG. 1, the cooling device further includes a detection feedback device 4 including a temperature detector 41 for detecting the surface temperature of the heat-generating object and a feedback controller 42 signally connected to the temperature detector 41, and the detection end of the temperature detector 41 can be inserted into the cooling chamber 11 and connected to the heat-generating element so as to detect the temperature of the surface of the heat-generating element. The feedback controller 42 can also be signally connected to the foaming device 2, specifically, to the air pump 21, and can adjust the power or gas flow rate of the air pump 21 according to the temperature range detected by the temperature detector 41, so as to realize the optimal matching between the number of bubbles and the surface temperature of the heat-generating element, and reduce unnecessary consumption.

[0030] 1, in one embodiment, the circulation device 3 includes a vapor outlet 31, one end of which is connected to the cooling chamber 11, a gas-liquid separator 32, and a reflux inlet 33, one end of which is connected to the cooling chamber 11, and the vapor outlet 31 and the reflux inlet 33 are all connected to the gas-liquid separator 32 through a pipeline. The cooling liquid vaporized by heat in the cooling chamber 11 can be output from the vapor outlet 31 and enter the gas-liquid separator 32 along the pipeline, and the vaporized cooling liquid can be liquefied again during transportation and stored in the separator 32, and then enter the cooling chamber 11 again through the reflux inlet 33, thereby realizing the circulation of the cooling liquid and reducing costs. The reflux inlet 33 may be located above or below the liquid level of the cooling liquid in the cooling chamber 11, and a first check valve 53 is provided between the gas-liquid separator 32 and the reflux inlet 33 to prevent the liquid cooling liquid or vaporized cooling liquid in the cooling chamber 11 from flowing from the reflux inlet 33 to the gas-liquid separator 32.

[0031] In addition, a condensing member 34, through which the cooling water passes, is further provided along the path of the pipeline on the outer wall of the pipeline for communicating with the gas-liquid separator 32 of the steam outlet 31. When the vaporized cooling liquid flows through the pipeline, the cooling water that has passed through the condensing member 34 can be more sufficiently liquefied.

[0032] In addition, the gas-liquid separator 32 is further provided with a pressure regulator 5 for regulating its internal pressure, and the pressure regulator 5 includes a second check valve 51 connected to the gas-liquid separator 32 and a pressure regulator 52 connected to the second check valve 51, the second check valve 51 can prevent the air pressure in the gas-liquid separator 32 from leaking to the outside, and the pressure regulator 52 is used to regulate the pressure in the gas-liquid separator 32. The pressure in the cooling chamber 11 may be controlled by the second check valve 51 and the pressure regulator 52, and generally, the pressure in the cooling chamber 11 can be set slightly higher than the external environmental pressure, or can be flexibly adjusted according to the needs of the work.

[0033] Each of the technical features of the above-mentioned embodiments can be combined in any combination. For the sake of brevity, not all possible combinations of each of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, any of them should be considered to be within the scope described in this specification.

[0034] The above examples merely illustrate some embodiments of the present invention, and although the description is specific and detailed, it should not be understood as limiting the scope of the claims. It should be understood that those skilled in the art to which the present invention pertains can make some modifications and improvements without departing from the concept of the present invention, and all of these are within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of the attached claims.

Claims

1. A cooling device for cooling a heat generating object, The cooling device includes a housing, a foaming device, and a circulation device. The inside of the housing has a sealable cooling chamber for containing a cooling liquid, and the heat-generating object can be placed in the cooling chamber containing the cooling liquid to be cooled; A part of the structure of the foaming device is immersed in the cooling liquid, and can generate bubbles in the cooling liquid, and can make the bubbles rise in the cooling liquid until they adhere to the surface of the heat generating object to be cooled; A cooling device, characterized in that the circulating device is connected to the housing and is used to collect and condense the evaporated cooling liquid, and then transport it back into the cooling chamber.

2. 2. The cooling device according to claim 1, wherein the foaming device includes an air pump for providing a non-condensable gas and a bubble generator connected to the air pump, the bubble generator being provided in the cooling chamber and positioned below a position of the heat-generating object when cooled so that the gas generated by the air pump can rise and impact the heat-generating object after being discharged through the bubble generator.

3. 3. The cooling apparatus of claim 2, wherein the bubble generator comprises a sintered metal, a ceramic-based air stone, or a showerhead with a few holes, and the bubble generator is capable of generating 5 or more bubbles per cubic millimeter.

4. 2. The cooling device of claim 1, further comprising a detection feedback device, the detection feedback device including a temperature detector for detecting a surface temperature of a heat-generating object, and a feedback controller signal-connected to the temperature detector, the feedback controller signal-connected to the foaming device, and capable of controlling the number of foams generated by the foaming device based on the temperature detected by the temperature detector.

5. 2. The cooling device according to claim 1, wherein the circulation device includes a steam outlet, one end of which communicates with the cooling chamber, a gas-liquid separator, and a reflux inlet, one end of which communicates with the cooling chamber, the steam outlet and the reflux inlet are both connected to the gas-liquid separator via pipes, the reflux inlet is located above or below the liquid level of the cooling liquid in the cooling chamber, and a first check valve is provided between the gas-liquid separator and the reflux inlet.

6. 6. The cooling device according to claim 5, wherein a condensing member through which cooling water passes is further provided in a pipe for communicating with the gas-liquid separator at the steam outlet, and the condensing member is used to liquefy the cooling liquid after evaporation.

7. 6. The cooling device according to claim 5, wherein the gas-liquid separator is further provided with a pressure adjusting device for adjusting an internal pressure thereof.

8. 8. The cooling system of claim 7, wherein the pressure regulating device includes a second check valve connected to the gas-liquid separator, and a pressure regulator connected to the second check valve.

9. 2. The cooling device according to claim 1, wherein water, an organic solvent or a mixed liquid is selected as the cooling liquid according to an operating temperature of a heat generating object.

10. 2. The cooling device according to claim 1, wherein an observation panel for observing the internal condition of the housing is provided on a side wall of the housing, and the observation panel is made of transparent quartz, acrylic or PC material.

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