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 increasingly obvious problems of narrow physical dimensions and ever-increasing total power density. As a result, the heat flow density of electronic devices is also increasing. The high temperatures caused by high heat flow density not only affect the performance of electronic devices, but can also burn out the entire device in severe cases.

[0003] In related art, immersion-type liquid-evaporative phase transition cooling technology is used to cool heat-generating elements inside electronic devices, and a large amount of latent heat is absorbed during the liquid-evaporative phase transition process, resulting in high cooling capacity and favorable heat transfer for high heat flow density in a small space. However, the cooling capacity of immersion-type liquid-evaporative phase transition cooling technology in related art is still required to be further improved, and its high heat dissipation capacity is somewhat insufficient. Summary of the Invention [Problem to be solved by the invention]

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

[0005] 1. A cooling device comprising: the cooling device comprises a housing, a foaming device, and a circulation device, the housing having a sealable cooling chamber for accommodating a cooling liquid therein, and the heat-generating object can be cooled by being placed in the cooling chamber containing the cooling liquid; A part 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 with a number of holes, and the bubble generator is capable of generating 5 or more bubbles per cubic millimeter.

[0008] In some embodiments of the cooling device, the cooling device further comprises a detection feedback device, which includes a temperature detector for detecting the surface temperature of a heat-generating object and a feedback controller signal-connected to the temperature detector, and the feedback controller signal-connected to the foaming device and is 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 vapor 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 vapor 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.

[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 element through which cooling water passes, and the condensing element 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 regulator 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 gas-liquid 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. [Effects of the Invention]

[0015] The implementation of the present invention has the following beneficial effects.

[0013] As can be seen from the above, by providing a bubble generating 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 vaporizing core, accelerating the evaporation of the liquid near the heating element and reducing the superheat of the surface of the heating element. Under low heat flow density conditions, the heating element can experience a pseudo-boiling phenomenon in which the surface superheat is less than zero. Under high heat flow density conditions, the bubbles can assist the vaporizing core in detaching from the surface of the heating element, increasing the upper limit of the heat exchange capacity, preventing or delaying the occurrence of film boiling, increasing the critical heat flow density, and further improving the phase change heat exchange cooling capacity of the equipment, thereby meeting the high heat dissipation needs. Furthermore, the cooling device provided by the embodiments of the present invention has a simple structure, a more compact volume, and reduces the filling cost of the working liquid. In order to more clearly explain the embodiments of the present invention or the prior art invention, 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 any creative efforts. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a structural schematic diagram showing a cooling device according to an embodiment of the present invention; [Figure 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 INVENTION

[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, and 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 to cool a heat-generating element of an electronic device. In one embodiment, referring to FIG. 1 , the cooling device includes a housing 1, a bubbling device 2, and a circulation device 3. The housing 1 has a sealable cooling chamber 11 for containing a cooling liquid, and the dashed line in the figure indicates the liquid level of the cooling liquid. The cooling chamber 11 must be sufficiently sealed to prevent liquid and pressure leakage. The heat-generating element can be placed in the chamber 11 containing the cooling liquid and cooled using the heat absorption by evaporation of the cooling liquid. The cooling liquid can be water, an organic solvent, or a mixed liquid. 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 depending on the operating temperature of the heating element.

[0019] 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 Figure 2, in order to clearly observe the internal condition of the housing 1, an observation plate 12 for observing the internal condition of the housing 1 can be installed at an appropriate position on the side wall of the housing 1, and the observation plate 12 can be embedded in or glued to the side wall of the housing 1, and the observation plate 12 can be made of transparent quartz, acrylic, PC material, etc.

[0020] The foaming device 2 includes a foaming unit, which can be disposed within a cooling chamber 11 containing a cooling liquid and can generate bubbles within the cooling liquid to impact the cooled surface of the heating element (hereinafter simply referred to as the "cooling surface"). This requires the foaming unit to be positioned below the heating element within the cooling chamber 11, allowing the bubbles generated by the foaming unit to rise through the cooling liquid and attach to the cooling surface. In this embodiment of the present invention, the heating element must be immersed in the cooling liquid when cooled, and the bubbles generated by the foaming unit must be easily detached from the cooling surface when they attach to the cooling surface, thereby reducing the temperature of the cooling surface. Therefore, the cooling surface of the heating element (the surface to which the bubbles attach) must be inclined at a certain angle with respect to a plane perpendicular to the direction in which the bubbles rise, with this angle being 15° or more. Generally, since 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, it can be said that the cooling surface must be inclined at an angle of 15° or more with respect to the horizontal plane. By inclining the cooling surface at a certain angle, bubbles on the cooling surface can roll along the cooling surface and be easily detached, allowing 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, collecting and condensing the evaporated cooling liquid, which can then be 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 equipment heat dissipation, battery thermal management, and data center heat dissipation. In the embodiment of the present invention, cooling of heat-generating elements in electronic devices is described as an example. Related technologies use immersion liquid evaporative phase change cooling technology to cool heat-generating elements. That is, the heat-generating element is immersed in a cooling liquid, and the cooling liquid absorbs heat by evaporating and absorbing heat. Because a large amount of latent heat is absorbed during the evaporative phase change process, the cooling capacity is far greater than that of conventional liquid-cooled plates or immersion single-phase liquid cooling, which is more advantageous for high-density heat transfer in a small space. Furthermore, the heat-generating element is in direct contact with the cooling liquid, reducing the thermal resistance required for indirect cooling systems by adding a thermal conductive material (e.g., thermal conductive paste or thermal conductive sheet). In an evaporative phase change system, the cooling liquid achieves cooling heat exchange through pool boiling. This eliminates the need for devices such as pumps to circulate the cooling liquid in an immersion 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) The degree of surface superheat of the heating element (i.e., the value at which 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 superheat, it cannot trigger the formation of an evaporation core on the surface. The evaporation core here refers to the bubbles generated when the cooling liquid near the heating element is heated by the heat of the heating element. The lower the surface superheat of the ideal heating element, the better, so as to avoid the temperature of the heating element becoming too high. (2) Frequency of detachment of vaporization cores and average particle size of detached bubbles The formation of a vaporization core on the surface of the heating element and its detachment 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 vaporization core detachment, the smaller the average particle diameter of the detached bubbles, and the higher the number of effective vaporization cores formed and the phase interface density (i.e., the contact area between the vaporization core and the surface of the heating element), which increases the heat exchange efficiency of the evaporation phase transition, the more heat is removed from the heating element, and the better the 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 changes, forming a continuous vapor film on the surface of the heating element, causing film boiling. This prevents heat exchange between the surface of the heating element and the liquid, resulting in a rapid increase in the temperature of the heating element. The higher the critical heat flow density, the more favorable the boiling phase transition cooling. The key to developing next-generation boiling phase transition cooling technology is to determine how to rapidly generate a vapor core at low superheat levels to trigger boiling, increase the frequency of vapor core detachment, and reduce the average particle size of detached bubbles, thereby increasing the effective vapor core and phase interface density, thereby preventing film boiling. Existing methods for promoting vapor core generation, increasing phase interface density, and preventing film boiling, such as electrolysis and surface modification, have drawbacks such as poor reinforcement and continuity, complex structure, and high cost, making large-scale commercialization difficult.

[0024] Compared with conventional phase-change liquid cooling, the cooling device of the present invention employs a bubble-generating device (2) that generates bubbles to flush the surface of the heating element. The bubbles can act as an evaporation core, significantly increasing the effective evaporation core and working density of the phase interface on the cooling surface, significantly accelerating the evaporation rate of the cooling liquid and improving heat exchange efficiency. Specifically, when the heating element is operating at low power and the surface temperature is lower than the boiling point of the cooling liquid, bubbles generated by the bubble-generating device (2) impinge on the surface of the heating element to be cooled. This replaces the evaporation core generated when the cooling liquid boils, causing the working liquid near the surface of the heating element to enter a pseudo-boiling state. After the bubbles attach to the surface of the heating element, the liquid in the vicinity vaporizes, absorbing a large amount of heat from the heating element. The vapor generated after evaporation is stored in the bubbles, accelerating the evaporation of the cooling liquid near the heating element and improving the phase-change heat exchange cooling capacity. The bubbles detach from the heating element along the surface of the heating element, absorbing heat from the heating element and reducing the surface superheat required for boiling to begin.

[0025] When the heating element is operating at high power and its surface temperature is higher than the boiling point of the cooling liquid, the high temperature of the heating element causes the cooling liquid to form a vapor core on the surface of the heating element. The bubbles generated by the bubble generator 2 flash over the surface of the heating element, merge with the vapor core formed by the cooling liquid on the surface of the heating element due to its temperature being higher than the boiling point, and then detach from the cooling surface, further assisting the vapor core to detach from the surface of the heating element and increasing the frequency of vapor core detachment. The assistance of the bubbles accelerates the timing of vapor core detachment from the heating element, reducing the average particle size at detachment and increasing the effective vapor core and phase interface density, thereby preventing or delaying 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, lowering 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 bubble generating 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 vaporizing core, accelerating the evaporation of the liquid near the heating element and reducing the superheat of the heating element surface. Under low heat flow density operating conditions, the heating element can experience a pseudo-boiling phenomenon in which the surface superheat is less than zero. Under high heat flow density operating conditions, the bubbles can assist the vaporizing core in detaching from the heating element surface, increasing the upper limit of heat exchange capacity, preventing or delaying the occurrence of film boiling, and increasing the critical heat flow density, thereby improving the phase change heat exchange cooling capacity of the equipment and meeting high heat dissipation needs. Furthermore, the cooling device provided by the embodiments of the present invention has a simple structure, a more compact volume, reducing the amount of working liquid required, and reducing 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 via an air supply pipe to supply gas to the bubble generator 22, which is the foaming part of the foaming device 2 that can discharge gas. The gas provided by the air pump 21 is a non-condensable gas, such as air, nitrogen gas, or argon gas. The gas flow rate can be controlled by an air valve inside the air pump 21 or by providing a flow control valve on the air supply pipe. The bubble generator 22 is installed in the cooling chamber 11 and is positioned below the position of the heat-generating object when cooled so that the gas generated by the air pump 21 can rise and impact the heat-generating object after being discharged through the bubble generator 22. The bubble generator 22 may be positioned 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 a sintered metal or ceramic air stone or a showerhead with a small number of holes. Regardless of whether it is an air stone or a showerhead, the holes for discharging air are all micropores with a pore size of 1 to 50 μm. By controlling the exhaust flow rate of the air pump 21, the pore size of the bubbles can be controlled so that the particle size upon contact with the cooling surface of the heating element is 0.1 to 200 μm, and the bubble density can be controlled so that five or more bubbles are generated per cubic millimeter. By providing micropores, a large number of microbubbles can be generated in the cooling liquid, increasing the frequency of detachment of the vaporization core, reducing the average particle size of the detached bubbles, increasing the effective phase interface density, and increasing the critical heat flow density, thereby preventing or delaying the occurrence of film boiling.

[0029] 1, in one embodiment, 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 signal-connected to the temperature detector 41. The detection end of the temperature detector 41 can be inserted into the cooling chamber 11 and connected to the heat-generating element to detect the temperature of the surface of the heat-generating element. The feedback controller 42 is also signal-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 based on the temperature range detected by the temperature detector 41, thereby achieving an optimal match between the number of bubbles and the surface temperature of the heat-generating element and reducing unnecessary consumption.

[0030] 1, in one embodiment, the circulation device 3 includes a vapor outlet 31 connected to the cooling chamber 11 at one end, a gas-liquid separator 32, and a reflux inlet 33 connected to the cooling chamber 11 at one end, and the vapor outlet 31 and the reflux inlet 33 are all connected to the gas-liquid separator 32 via a pipeline. The cooling liquid vaporized by heat in the cooling chamber 11 is output from the vapor outlet 31 and can enter the gas-liquid separator 32 along the pipeline. The vaporized cooling liquid can be liquefied again during transportation and stored in the separator 32, and then re-enter the cooling chamber 11 via 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] A condenser 34, through which cooling water passes, is further provided along the path of the pipe on the outer wall of the pipe that connects the steam outlet 31 to the gas-liquid separator 32. When the vaporized cooling liquid flows through the pipe, the cooling water that has passed through the condenser 34 can be more fully liquefied.

[0032] 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 adjuster 52 connected to the second check valve 51. The second check valve 51 prevents the air pressure in the gas-liquid separator 32 from leaking to the outside, and the pressure adjuster 52 is used to adjust 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 adjuster 52. In general, the pressure in the cooling chamber 11 can be set slightly higher than the external environmental pressure, or can be flexibly adjusted according to work needs.

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

[0034] The above examples merely illustrate some embodiments of the present invention, and although the descriptions are specific and detailed, they 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 fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined based on the scope of the appended claims.

Claims

1. In a cooling device for cooling a heat-generating object, the cooling device includes a housing, a foaming device, and a circulation device; The interior of the housing has a sealable cooling chamber for containing a cooling liquid, and the heat-generating object can be cooled by being placed in the cooling chamber containing the cooling liquid; A part of the foaming device is immersed in the cooling liquid, and can generate bubbles in the cooling liquid, and can cause the bubbles to 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; 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 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; A cooling device characterized in that the surface of the heat-generating object to be cooled and a plane perpendicular to the direction in which the bubbles rise are inclined, and the surface of the heat-generating object to be cooled is inclined at an angle of 15° or more with respect to the plane perpendicular to the direction in which the bubbles rise, thereby improving the frequency of detachment of the evaporation core.

2. 10. The cooling device of claim 1, wherein the bubble generator comprises a sintered metal, a ceramic-based air stone, or a showerhead with a number of holes, and the bubble generator is capable of generating five or more bubbles per cubic millimeter.

3. 2. The cooling device of claim 1, further comprising 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.

4. 2. The cooling device of claim 1, wherein the circulation device includes a vapor 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 vapor outlet and the reflux inlet both communicating with the gas-liquid separator via pipes, the reflux inlet being located above or below the liquid level of the cooling liquid in the cooling chamber, and a first check valve being provided between the gas-liquid separator and the reflux inlet.

5. 5. The cooling device according to claim 4, wherein a condensing member through which cooling water passes is further provided in a pipe for communicating with the gas-liquid separator at the vapor outlet, and the condensing member is used to liquefy the cooling liquid after evaporation.

6. 5. The cooling device according to claim 4, wherein the gas-liquid separator is further provided with a pressure adjusting device for adjusting the internal pressure thereof.

7. 7. The cooling system according to claim 6, 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.

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

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

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