Microchannel Phase Change Heat Transfer System

Abstract

The present invention discloses a microchannel phase change heat transfer system, which includes a heat dissipation body; the heat dissipation body has a microchannel unit, and a bubbling structure is provided in the microchannel unit; the heat dissipation body also has a jet unit for adding a jet into the microchannel unit. Since the bubbling structure is provided in the microchannel unit, the refrigerant in the microchannel unit can be kept in the boiling heat transfer stage, so that the heat exchange mode of the phase change heat transfer system is phase change heat transfer, which improves the heat transfer coefficient of the phase change heat transfer system and reduces the pressure drop loss; moreover, since the jet unit capable of adding a jet into the microchannel unit is provided, the turbulence degree of the fluid in the microchannel unit can also be increased, and the degree of uniform mixing of the gas-liquid two-phase flow is improved, and the temperature equalization effect is good, which effectively solves the problem of unstable flow boiling in the traditional microchannel heat exchanger during the phase change heat transfer process.

Description

Technical Field

[0001] The invention relates to a heat exchange device, in particular to a microchannel phase change heat exchange system. Background Art

[0002] With the rapid development of the microelectronics industry, the integration of microelectronic devices continues to increase, the size of microelectronic devices is getting smaller and smaller, while the heat generation power is getting larger and larger, which leads to the continuous increase in the heat flux density of the microelectronic devices themselves. If the heat generated by the microelectronic devices cannot be released to the environment in time, the accumulated heat will cause the temperature of the electronic devices to continue to rise. Higher temperatures will not only affect the normal performance of electronic devices, but in serious cases, they will also burn electronic devices and even cause safety accidents such as fires. Therefore, high heat flux density electronic devices are in urgent need of an efficient cooling device to ensure their safe and stable operation.

[0003] Microchannel heat sinks are considered to be one of the most effective heat dissipation methods for microelectronic devices due to their compact structure and large heat dissipation area. At the same time, compared with single-phase convection heat transfer, phase change heat transfer has a higher heat transfer coefficient. Therefore, keeping the refrigerant in the microchannel heat sink in the boiling heat transfer stage is of great significance for improving the system's heat transfer performance and reducing pressure drop losses.

[0004] However, when traditional microchannel heat sinks perform phase change heat transfer, there will be phenomena such as uneven distribution of gas-liquid two-phase flow, gas phase blockage in the flow channel, and rapid growth of bubbles causing two-phase flow reflux. These phenomena lead to unstable flow boiling in the first microchannel, which seriously affects the cooling and temperature equalization performance of traditional microchannel heat sinks. Therefore, how to enhance the flow boiling stability of microchannel heat sinks during phase change heat transfer, enhance heat transfer performance, and meet the cooling and temperature equalization requirements of high heat flux density electronic devices is still a technical problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve at least one of the aforementioned problems, according to one aspect of the present invention, a microchannel phase change heat transfer system is provided.

[0006] The microchannel phase-change heat dissipation system comprises a heat dissipation body; the heat dissipation body comprises a microchannel unit, in which a bubbling structure is arranged; the heat dissipation body also comprises a jet unit for adding a jet into the microchannel unit.

[0007] Since a bubbling structure is provided in the microchannel unit, the refrigerant in the microchannel unit can be kept in the nucleate boiling heat transfer stage, so that the heat exchange mode of the phase change heat exchange system is phase change heat transfer, which improves the heat transfer coefficient of the phase change heat exchange system and reduces the pressure drop loss; moreover, the present invention couples the jet unit with the microchannel unit with the bubbling structure, so that the turbulence of the fluid in the microchannel unit can be increased by adding a jet to the microchannel unit through the jet unit, thereby improving the degree of uniform mixing of the gas-liquid two-phase flow, and achieving a good temperature equalization effect, thereby effectively solving the problem of unstable flow boiling in the traditional microchannel heat exchanger during the phase change heat transfer process.

[0008] In some embodiments, the microchannel unit includes at least two first microchannels arranged in parallel; the bubble structure is a recessed structure arranged on the wall of the first microchannel; exemplarily, the recessed structure is a cavity or a groove; the wall of the first microchannel includes a first bottom wall located at the bottom of the first microchannel and a first side wall and a second side wall located on the side of the first microchannel and oppositely arranged; the recessed structures on the first bottom wall, the first side wall and the second side wall of the same first microchannel are arranged alternately along the length direction of the first microchannel.

[0009] Since the recesses and grooves can serve as the vaporization core during boiling heat transfer, the wall superheat at the starting point of boiling of the microchannel heat sink can be reduced; when recessed structures are provided on the first side wall, the second side wall and the first bottom wall, the number of recessed structures can be greatly increased, which can not only greatly increase the number of bubbles generated, but also improve the uniformity of bubble generation; moreover, the positions of bubbles generated in the first microchannel can be staggered by the staggered arrangement of the recessed structures, which can not only prevent the bubbles from growing, but also make it easier to induce oscillation of the fluid in the first microchannel.

[0010] In some embodiments, the recessed structures on at least one of the first bottom wall, the first side wall and the second side wall are evenly spaced, so that the boiling of the fluid in the first microchannel can occur more evenly, so as to further improve the flow boiling stability of the phase change heat transfer system. In particular, the spacing between two adjacent recessed structures arranged on the first side wall and the second side wall is twice the spacing between two adjacent recessed structures arranged on the first bottom wall, so that the recessed structures adjacent to the recessed structures on each first bottom wall are recessed structures on different side walls, that is, the recessed structures adjacent to one side of the recessed structures on each first bottom wall along the length direction of the first microchannel are recessed structures on the first side wall, and the recessed structures adjacent to the other side are recessed structures on the second side wall, so that when the fluid in the first microchannel flows along the length direction of the first microchannel, it will alternately encounter the recessed structures on the first side wall, the recessed structures on the first bottom wall and the recessed structures on the second side wall to generate bubbles, so as to further induce the oscillation of the fluid in the first microchannel. Furthermore, the distance between the recessed structures arranged on the first side wall and the second side wall is equal to the distance between two adjacent recessed structures arranged on the first bottom wall, so that the distance between all the recessed structures along the length direction of the first microchannel is equal, further ensuring the uniformity of boiling of the fluid in the first microchannel.

[0011] In some embodiments, the jet unit includes perforations arranged along the length direction of the first microchannel. Thus, the fluid can be supplemented with fresh fluid during the flow along the length direction of the first microchannel, thereby effectively suppressing the temperature rise effect of the fluid itself, causing the gas inside the bubbles in the fluid to condense, and then causing the bubble volume to cool down and shrink, so as to enhance the nucleate boiling state of the phase change heat transfer system, improve the uniformity of gas-liquid two-phase flow distribution, avoid gas phase blockage in the flow channel, rapid restricted growth of bubbles causing two-phase flow reflux, and further improve the temperature uniformity of the phase change heat transfer system.

[0012] In some embodiments, the perforations are located above the first microchannel; and the perforations are staggered with the recessed structures on the first bottom wall, and / or the perforations and the recessed structures on the first sidewall and the second sidewall are correspondingly arranged along the length direction of the first microchannel.

[0013] Therefore, when the perforations and the recessed structures on the first bottom wall are arranged in an alternating manner, it is possible to avoid interference of the jet impact on the bubble generation process on the recessed structures on the first bottom wall; when the perforations and the recessed structures on the first side wall and the second side wall are arranged correspondingly along the length direction of the first microchannel, the perforations can be located directly above the recessed structures on the first side wall and the second side wall, or can be a certain distance away from the recessed structures on the first side wall and the second side wall, as long as there is a recessed structure on the first side wall or the second side wall on the same length of the first microchannel as the perforations in the length direction of the first microchannel, so that the bubbles generated on the recessed decoupling strands on the first side wall and the second side wall can cause the jet beam at that location to deviate, and when the bubbles at that location disappear, the jet beam at that location can return to its original position, so that the jet beam can spontaneously oscillate perpendicular to the mainstream direction in the first microchannel, so as to further enhance the turbulence of the fluid, break up larger bubbles in the first microchannel, thereby improving the uniformity of mixing of the gas-liquid two-phase flow, and further improving the stability of flow boiling.

[0014] In some embodiments, the recessed structures provided on the first side wall and the second side wall are grooves, and the grooves are arranged along the vertical direction; and the recessed structures provided on the first bottom wall are holes.

[0015] Therefore, by increasing the number and volume of bubbles generated in the recess in the vertical direction, the ability of the bubbles there to cause the jet beam to deviate can be improved, thereby increasing the oscillation of the jet beam, thereby enhancing the turbulence of the fluid and improving the uniformity of the mixing of the gas-liquid two-phase flow; and, since the recessed structure arranged on the first bottom wall is a recess with a smaller cross-sectional area than the groove, the first microchannel can be prevented from being blocked due to the generation of larger bubbles in the recess.

[0016] In some embodiments, the heat dissipation body further has a fluid distribution cavity for evenly distributing the refrigerant to each first microchannel, so that the refrigerant can be evenly distributed to each first microchannel, thereby avoiding failure to achieve the optimal heat dissipation effect due to uneven distribution of the refrigerant.

[0017] In some embodiments, the heat dissipation body also has a first inlet connecting the fluid distribution cavity with the outside; the fluid distribution cavity for evenly distributing the refrigerant to each first microchannel is realized as follows: the heat dissipation body also has a second microchannel surrounded by guide ribs and a second bottom wall, corresponding one to one with the first microchannel, the second microchannel is connected to the first microchannel through a perforation provided on the second bottom wall, the first inlet is provided on one of the outermost guide ribs, and the height of the guide rib increases with the increase of the distance between it and the first inlet.

[0018] Thus, the refrigerant introduced through the first inlet can be evenly distributed to each second microchannel.

[0019] In some embodiments, at least a portion of the surface of the recessed structure is configured as a super-hydrophobic surface; and at least a portion of the surface of the inner surface of the first microfluidic channel other than the recessed structure is configured as a super-hydrophilic surface.

[0020] Therefore, by rationally combining hydrophilic and hydrophobic surfaces on the wall of the first microchannel, that is, utilizing the bubbling-prone property of the hydrophobic surface of the vaporization core, the system can enter the boiling state earlier at a lower heat flux density and reduce the wall superheat; the hydrophilic surface on the periphery can timely hinder the growth of bubbles at the hydrophobic points, effectively avoiding the formation of an air film near the wall, and improving the critical heat flux density of the system.

[0021] In some embodiments, the heat dissipation body further has a fluid collection cavity, and the first microchannel is connected to the outside through the fluid collection cavity; preferably, the fluid collection cavity is arranged at both ends of the first microchannel in the length direction.

[0022] Thus, the refrigerant injected into the microchannel unit through the jet unit can first play a role in the microchannel unit, and then be discharged to the outside of the phase change heat exchange system through the fluid collection chamber; moreover, when the fluid collection chamber is set to the end of the length direction of the first microchannel, the mainstream direction of the fluid in the first microchannel flows along the length direction of the first microchannel, and because the concave structure as the vaporization core is set on the wall surface of the first microchannel, the movement direction of the bubbles formed on the concave structure is perpendicular to the mainstream direction of the fluid, which will disturb the flow of the fluid in the first microchannel, causing the fluid in the first microchannel to oscillate, thereby further improving the uniformity of the mixing of the gas-liquid two-phase in the first microchannel, enhancing the stability of the boiling flow in the first microchannel, strengthening the boiling heat exchange, and avoiding the occurrence of uneven distribution of the gas-liquid two-phase, gas phase blockage in the flow channel, and rapid restricted growth of bubbles causing two-phase flow reflux. When the fluid collection chamber is set at both ends of the length direction of the first microchannel, the uniformity of the mixing of the gas-liquid two-phase in the first microchannel can be further improved.

[0023] In some embodiments, the heat dissipation body includes a detachably connected jet plate and a microchannel heat exchange plate; the microchannel unit is arranged on the microchannel heat exchange plate; and the jet unit is arranged on the jet plate, so as to facilitate the processing of the microchannel unit and the jet unit.

[0024] In some embodiments, the heat dissipation body also includes a cover plate detachably connected to the jet plate; the cover plate, the jet plate and the microchannel heat exchange plate are arranged in sequence from top to bottom; the fluid collection chamber includes a first collection chamber provided on the microchannel heat exchange plate, and a second collection chamber provided on the jet plate and connected to the first collection chamber; the second collection chamber is connected to the outside through a first outlet provided on the cover plate.

[0025] When in use, the refrigerant first enters the fluid distribution cavity from the first inlet on the wall of one side of the jet plate, and then, under the action of the guide ribs, the refrigerant is evenly distributed to each second microchannel. Under the action of pressure, the refrigerant entering the second microchannel of the jet plate passes through the perforations in the form of jet impact and enters the first microchannel on the microchannel heat exchange plate below for flow boiling heat exchange. On the microchannel heat exchange plate, in each first microchannel, the fluid after heat exchange flows along the length of the first microchannel to the two ends of the first microchannel, and respectively converges in the first collection cavities at the two ends of the first microchannel; the fluid in the first collection cavities at the two ends of the microchannel heat exchange plate flows upward under the action of pressure, passes through the second collection cavities at the two ends of the jet plate, and finally discharges the system from the first outlet on the cover plate, realizing the heat exchange of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of a microchannel phase change heat transfer system according to one embodiment of the present invention;

[0027] Figure 2 for Figure 1 A schematic cross-sectional structure diagram of the microchannel phase change heat transfer system along the AA direction;

[0028] Figure 3 for Figure 1 A schematic cross-sectional structure diagram of the microchannel phase change heat transfer system in another direction;

[0029] Figure 4 for Figure 1 Schematic diagram of the microchannel phase change heat transfer system in disassembled state;

[0030] Figure 5 for Figure 4 A schematic diagram of the structure of a microchannel heat exchange plate of a microchannel phase change heat exchange system shown;

[0031] Figure 6 for Figure 5 A schematic structural diagram of a longitudinal section of a microchannel heat exchange plate shown;

[0032] Figure 7 for Figure 5 A schematic cross-sectional structure diagram of the microchannel heat exchange plate in use;

[0033] Figure 8 for Figure 4 A schematic diagram of the structure of a jet plate of a microchannel phase change heat transfer system shown;

[0034] Fig. 9 for Figure 8 A schematic diagram of the cross-sectional structure of the jet plate along the BB direction;

[0035] Figure numerals: 20, heat dissipation body; 21, cover plate; 211, first outlet; 22, jet plate; 220, second microchannel; 221, perforation; 222, first inlet; 223, guide rib; 224, second bottom wall; 225, second collecting chamber; 226, second outer plate; 227, first inner plate; 23, microchannel heat exchange plate; 230, microchannel unit; 231, first microchannel; 232, recess; 233, first side wall; 234, first bottom wall; 235, first collecting chamber; 236, first outer plate; 237, groove; 238, second side wall. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0037] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include" and "comprise" include not only those elements, but also other elements that are not explicitly listed, or also include elements inherent to such processes, methods, articles or equipment. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the existence of other identical elements in the process, method, article or equipment that includes the elements. The terms used in this article are generally commonly used terms by those skilled in the art. If they are inconsistent with commonly used terms, the terms in this article shall prevail.

[0038] In this article, the term "self-oscillation" is also called self-sustained oscillation, self-excited oscillation or self-vibration, which refers to a stable periodic motion with a fixed frequency and amplitude generated in the system when there is no external periodic changing signal.

[0039] In this article, the term "microchannel" is also called a microchannel heat exchanger, which is a heat exchanger with a channel equivalent diameter of 10-1000μm. This type of heat exchanger has dozens of fine first micro channels in the flat tube, which are connected to the circular header at both ends of the flat tube. The baffle is set in the header to divide the heat exchanger flow channel into several processes.

[0040] In this article, the term "coupling" refers to the phenomenon that two or more systems or two forms of motion influence each other and even combine through interaction.

[0041] In this article, the term "jet" refers to a flow of fluid that is ejected from a nozzle, orifice, slit, or is mechanically propelled and mixed with the surrounding fluid.

[0042] In this article, the term "heat flux density" is also called heat flux, generally represented by q, and is defined as: the amount of heat passing through a unit cross-sectional area of ​​an object per unit time.

[0043] In this article, the term "heat sink" refers to an object whose temperature does not change with the amount of heat energy transferred to it, and it can be the atmosphere, the earth, or other objects used to dissipate heat.

[0044] In this article, the term "flow instability" refers to the phenomenon of flow oscillation, drift or reversal. Flow oscillation has many causes, which may be caused by bubble generation or unreasonable mechanical resistance caused by design or processing.

[0045] As used herein, the term "superheat" refers to the difference between the superheat temperature and the saturation temperature of a refrigerant at the same evaporation pressure in a refrigeration cycle.

[0046] In this context, the term "superhydrophobic" refers to a new type of material that can clean itself wherever it needs to be cleaned and can also be placed on metal surfaces to prevent corrosion from the outside world.

[0047] In this article, the term "staggered" means that the two are not arranged correspondingly or facing each other, that is, the two are staggered.

[0048] As used herein, the term "bubble structure" refers to a structure capable of causing bubbles to be generated in the fluid in the microchannel unit, such as a recess on the wall of the microchannel unit.

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0050] Figures 1 to 9 A microchannel phase change heat transfer system according to an embodiment of the present invention is schematically shown.

[0051] like Figures 2 to 4 As shown, the microchannel phase change heat transfer system includes a heat dissipation body 20; the heat dissipation body 20 has a microchannel unit 230, and a bubbling structure is provided in the microchannel unit 230. The bubbling structure is used to make the fluid flowing through the microchannel unit 230 preferentially form bubbles at the location of the bubbling structure; the heat dissipation body 20 also has a jet unit for adding a jet into the microchannel unit 230.

[0052] As one embodiment of the microchannel unit 230, Figure 4and Figure 5 As shown in Figure 5 , the microchannel unit 230 includes at least two first microchannels 231 arranged in parallel. For example, it includes two, four, five, seven, eight, etc. first microchannels 231 arranged in parallel side by side in sequence; the bubbling structure is a recessed structure integrally formed or processed on the wall surface of the first microchannel 231, such as a recess 232 or a groove 237. In this article, the wall surface of the first microchannel 231 refers to the inner surface of the solid structure that encloses the first microchannel 231. Exemplarily, the wall surface of the first microchannel 231 includes a first bottom wall 234 located at the bottom of the first microchannel 231, and the wall surface of the first microchannel 231 also includes a first side wall 233 and a second side wall 238 that are located on the side of the first microchannel 231 and are oppositely arranged. So that when the fluid flows through the first microchannel 231, bubbles can be preferentially formed on the surface of the recess 232 or the groove 237, shortening the bubble generation time and reducing the wall superheat at the boiling onset point of the microchannel heat sink. Exemplarily, the shape of the recess 232 or the groove 237 can be selected as needed. For example, the recess 232 or the groove 237 is an arc-shaped groove with a semicircular cross-section (as shown in Figure 6 and Figure 7 ), a rectangular groove with a "匚"-shaped cross-section, or a groove with a "V"-shaped cross-section, or it can also be a recessed structure of any other shape as long as there is a recessed part on the recess 232 or the groove 237. In the present invention, the setting method of the first microchannel 231 can refer to the setting method of the microchannel in the prior art, and the present invention does not limit the specific setting method of the first microchannel 231. Figure 6 and Figure 7 shown), a rectangular groove with a "匚"-shaped cross-section, or a groove with a "V"-shaped cross-section, or it can also be a recessed structure of any other shape as long as there is a recessed part on the recess 232 or the groove 237. In the present invention, the setting method of the first microchannel 231 can refer to the setting method of the microchannel in the prior art, and the present invention does not limit the specific setting method of the first microchannel 231.

[0053] The microchannel phase change heat exchange system of the present invention solves the problem of unstable flow boiling in the phase change heat transfer process of the traditional microchannel heat exchanger by setting a bubbling structure in the microchannel unit 230. At the same time, the microchannel unit 230 with the bubbling structure is coupled with a jet unit that can inject jets into the microchannel unit 230, so that the refrigerant in the microchannel unit 230 can be maintained in the nucleate boiling heat transfer stage. While the heat exchange method of this phase change heat exchange system is phase change heat transfer, the turbulence degree of the fluid in the microchannel unit 230 can be increased by jets, and the degree of uniform mixing of the gas-liquid two-phase flow can be improved.

[0054] As one of the preferred embodiments of the recessed structure, as shown in Figure 2 and Figures 4 to 7 Figure 2 and Figures 4 to 7As shown, at least two recessed structures are provided in each first microchannel 231, and the recessed structures (cavities 232 and / or grooves 237) in the same first microchannel 231 are arranged along the length direction of the first microchannel 231, so that when the fluid in the first microchannel 231 flows in the first microchannel 231, bubbles can be continuously generated on the recessed structures to ensure the boiling heat transfer effect. Further, the recessed structures in the same first microchannel 231 are arranged in a staggered manner along the length direction of the first microchannel 231, that is, the recessed structures on different wall surfaces of the first microchannel 231 are arranged at different positions along the length direction of the first microchannel 231, so that the positions where bubbles are generated in the first microchannel 231 are staggered, thereby making it easier to induce oscillation of the fluid in the first microchannel 231.

[0055] As another preferred embodiment of the recessed structure, Figure 2 and Figures 4 to 7As shown, the recessed structures (cavities 232 and / or grooves 237) on any wall surface of each first microchannel 231 are arranged at equal intervals. The recessed structures on any one of the first bottom wall 234, the first side wall 233 and the second side wall 238 may be arranged at equal intervals, or the recessed structures on any two of the first bottom wall 234, the first side wall 233 and the second side wall 238 may be arranged at equal intervals, or the recessed structures on the first bottom wall 234, the first side wall 233 and the second side wall 238 may be arranged at equal intervals. For example, the recessed structures may be arranged in at least one of the following ways: the recessed structures are arranged at equal intervals along the length direction of the first microchannel 231, or are arranged at equal intervals along the width direction of the first microchannel 231, or are arranged at equal intervals along the height direction of the first microchannel 231. This allows the boiling of the fluid in the first microchannel 231 to occur more evenly, so as to further improve the flow boiling stability of the phase change heat transfer system. Preferably, the spacing between two adjacent recessed structures on the first side wall 233 is twice the spacing between two adjacent recessed structures on the first bottom wall 234, and the spacing between two adjacent recessed structures on the second side wall 238 is twice the spacing between two adjacent recessed structures on the first bottom wall 234, so that the recessed structures adjacent to each recessed structure on the first bottom wall 234 are recessed structures on different side walls. Thus, when the fluid in the first microchannel 231 flows along the length direction of the first microchannel 231, it will alternately encounter the recessed structures on the first side wall 233, the recessed structures on the first bottom wall 234, and the recessed structures on the second side wall 238, generating bubbles, thereby further inducing oscillation of the fluid in the first microchannel 231. Furthermore, the distance between the recessed structure arranged on the first side wall 233 and the adjacent two recessed structures arranged on the first bottom wall 234 is equal, and the distance between the recessed structure arranged on the second side wall 238 and the adjacent two recessed structures arranged on the first bottom wall 234 is equal, so that the distances between all the recessed structures along the length direction of the first microchannel 231 are equal, further ensuring the uniformity of boiling of the fluid in the first microchannel 231 and the uniformity of mixing of gas-liquid two phases.

[0056] As another preferred embodiment of the recessed structure, at least the surface of the recessed structure is set to a super-hydrophobic surface. For example, a coating of a super-hydrophobic material is coated on the surface of the recessed structure to further increase the speed at which bubbles are formed on the surface of the recessed structure. The super-hydrophobic material can be any super-hydrophobic material commonly used in the prior art, and the present invention does not limit the specific material of the super-hydrophobic material.

[0057] As one of the embodiments of the first microchannel 231, at least part of the surface of the wall of the first microchannel 231 except the recessed structure is set as a super hydrophilic surface. For example, at least part of the surface of the wall of the first microchannel 231 except the recessed structure is coated with a coating of a super hydrophilic material to ensure that the phase change heat transfer system has a higher critical heat flux density, wherein the super hydrophilic material can be the super hydrophilic material commonly used in the prior art, and the present invention does not limit the specific material of the super hydrophilic material.

[0058] As another embodiment of the first microchannel 231, at least the surface of the concave structure is set as a super hydrophobic surface, and at least part of the surface of the wall of the first microchannel 231 except the concave structure is set as a super hydrophilic surface. The present invention has the effect of strengthening boiling heat transfer by setting a bubbling structure on the wall of the microchannel and setting a hydrophilic and hydrophobic combined surface; moreover, the set super hydrophilic surface can also timely hinder the growth of bubbles at the super hydrophobic surface, and can effectively avoid the formation of an air film near the wall, thereby improving the critical heat flux density of the phase change heat transfer system.

[0059] As another embodiment of the first microchannel 231, Figure 4 and Figure 5 As shown, the first microchannel 231 is a groove-shaped structure surrounded by the first side wall 233, the second side wall 238 and the first bottom wall 234. Specifically, the first microchannel 231 is surrounded by the partition and the first bottom side plate. The first side wall 233 is one of the side surfaces of the partition, the second side wall 238 is the side surface of the partition opposite to the first side wall 233, and the first bottom wall 234 is one of the surfaces of the first bottom side plate. The wall surface of the first microchannel 231 includes the first side wall 233, the second side wall 238 and the first bottom wall 234; the recessed structure is arranged on at least one of the first side wall 233, the second side wall 238 and the first bottom wall 234. When the recessed structure is arranged on the first side wall 233, the second side wall 238 and the first bottom wall 234, the number of recessed structures can be greatly increased, which can not only greatly increase the number of bubbles generated, but also improve the uniformity of bubble generation. When the recessed structures are arranged along the length direction of the first microchannel 231, since the mainstream direction of the fluid in the first microchannel 231 flows along the length direction of the first microchannel 231, the movement direction of the bubbles formed on the recessed structures is perpendicular to the mainstream direction of the fluid, which will disturb the flow of the fluid in the first microchannel 231, causing the fluid in the first microchannel 231 to oscillate, thereby further improving the uniformity of the mixing of the gas-liquid two-phase in the first microchannel 231, enhancing the stability of the flow boiling in the first microchannel 231, strengthening the boiling heat exchange, and avoiding the occurrence of uneven distribution of the gas-liquid two-phase, gas phase blockage in the flow channel, and rapid restricted growth of bubbles causing two-phase flow reflux (such as Figure 7As shown). Preferably, the recessed structure provided on the first side wall 233 and the second side wall 238 penetrates the top of the first side wall 233 along the height direction of the first side wall 233 and the second side wall 238, that is, the recessed structure on the first side wall 233 and the second side wall 238 is a vertically arranged groove 237, so as to increase the number and size of bubbles generated by increasing the cross-sectional area of ​​the recessed structure, and improve the ability of the bubbles there to cause the jet beam to deviate, so as to increase the oscillation of the jet beam, thereby enhancing the turbulence of the fluid and improving the uniformity of the mixing of the gas-liquid two-phase flow; moreover, the recessed structure on the first side wall 233 and the second side wall 238 is arranged as a vertically arranged groove 238 that penetrates the top of the first side wall 233 and the second side wall 238, so that the processing of the groove 238 can be more convenient and quick.

[0060] In some preferred embodiments, Figure 2 and Figure 4 As shown, the heat dissipation body 20 also has a fluid collection chamber, and the first microchannel 231 is connected to the outside through the fluid collection chamber. Preferably, the fluid collection chamber is at least arranged at at least one end in the length direction of the first microchannel 231. Thus, the refrigerant injected into the microchannel unit 230 through the jet unit can first act in the microchannel unit 230, and then be discharged to the outside of the phase change heat dissipation system through the fluid collection chamber; moreover, when the fluid collection chamber is arranged at the end in the length direction of the first microchannel 231, the mainstream direction of the fluid in the first microchannel 231 flows along the length direction of the first microchannel 231, and since the concave structure as the vaporization core is arranged on the wall surface of the first microchannel 231, the movement direction of the bubbles formed on the concave structure is perpendicular to the mainstream direction of the fluid, which will disturb the flow of the fluid in the first microchannel 231, causing the fluid in the first microchannel 231 to oscillate. More preferably, the fluid collecting chambers are arranged at both ends of the first microchannel 231 in the length direction to further improve the uniformity of mixing of the gas-liquid two-phase in the first microchannel 231 .

[0061] As one of the preferred embodiments of the jet unit, Figure 2 and Figure 4As shown, the jet unit includes perforations 221 arranged along the length direction of the first microchannel 231. In this way, the fluid can be supplemented with fresh cold fluid during the flow along the first microchannel 231, thereby effectively suppressing the temperature rise effect of the fluid itself, causing the gas inside the bubbles in the fluid to condense, and then causing the bubble volume to cool down and shrink, so as to enhance the nucleate boiling state of the phase change heat transfer system, improve the uniformity of the gas-liquid two-phase flow distribution, avoid the gas phase blockage in the flow channel, the rapid growth of bubbles to limit the occurrence of two-phase flow reflux and the like, and further improve the temperature uniformity of the phase change heat transfer system. Furthermore, the perforation 221 is located above the first microchannel 231, that is, the perforation 221 is located on the side of the first microchannel 231 away from the first bottom wall 234, so that the refrigerant injected by the perforation 221 can flow along the injection direction perpendicular to the perforation 221 (the length direction of the first microchannel 231) to increase the probability of the refrigerant contacting the recessed structure provided in the first microchannel 231, thereby enhancing the nucleate boiling state of the refrigerant; moreover, the jet is injected into the first microchannel 231 from top to bottom, so that the refrigerant injected into the first microchannel 231 through the perforation 221 can maintain a good jet effect under the action of its own gravity. Furthermore, the perforations 221 and the recessed structures on the first bottom wall 234 are arranged in an alternating manner, and / or the perforations 221 and the recessed structures on the first side wall 233 and / or the second side wall 238 are arranged correspondingly along the length direction of the first microchannel 231; wherein, the staggered arrangement is similar to the aforementioned staggered distribution specific implementation method, which will not be repeated here; the perforations 221 and the recessed structures on the first side wall 233 and the second side wall 238 are arranged correspondingly along the length direction of the first microchannel 231, and the two may be aligned in the vertical direction or staggered in the vertical direction, as long as the two are at the same length position of the first microchannel 231.Thus, when the perforations 221 and the recessed structures on the first bottom wall 234 are staggered, it is possible to avoid interference of the jet impact on the process of generating bubbles on the recessed structures of the first bottom wall 234. Exemplarily, the recessed structures on the first bottom wall 234 are recessed holes 232 or grooves extending in a direction perpendicular to the length direction of the first microchannel 231. Preferably, the recessed structures on the first bottom wall 234 are recessed holes 232 with a smaller cross-section, so as to avoid large bubbles generated due to the larger size of the recessed structures, thereby causing the first microchannel 231 to be blocked by large bubbles. When the perforations 221 and the recessed structures on the first side wall 233 or the second side wall 238 are correspondingly arranged along the length direction of the first microchannel 231, the bubbles generated on the recessed structures on the first side wall 233 or the second side wall 238 may cause the jet beam thereto to deviate. When the bubble at that place disappears, the jet beam at that place can return to its original position, so that the jet beam can spontaneously oscillate perpendicular to the mainstream direction in the first microchannel 231, so as to further enhance the turbulence of the fluid, break the larger bubbles in the first microchannel 231, thereby improving the uniformity of the mixing of the gas-liquid two-phase flow, and further improving the stability of the flow boiling; preferably, the recessed structure on the first side wall 233 and the second side wall 238 is a groove 237 with a larger cross-section than the recess 232, so as to increase the volume of the bubbles generated by the recessed structure on the first side wall 233 and the second side wall 238, thereby enhancing the ability of the bubbles at that place to cause the jet beam to deviate and improving the oscillation of the jet beam; further, the groove 237 is arranged in the vertical direction, so that the bubbles generated on the groove 237 can continuously act on the jet beam.

[0062] In some embodiments, the heat dissipation body 20 further has a fluid distribution cavity for evenly distributing the coolant to each first microchannel 231. Figure 3 , Figure 4 , Figure 8 and Fig. 9As shown, the heat dissipation body 20 also has a first inlet 222 that connects the fluid distribution chamber with the outside; the fluid distribution chamber that evenly distributes the refrigerant to each first microchannel 231 is realized as follows: the heat dissipation body 20 also has a second microchannel 220 surrounded by guide ribs 223 and a second bottom wall 224, which corresponds one to one with the first microchannel 231, and the second microchannel 220 is connected with the first microchannel 231 through a perforation 221 provided on the second bottom wall 224, and the first inlet 222 is provided on one of the outermost guide ribs 223, and the height of the guide rib 223 increases with the increase of the distance between it and the first inlet 222. Specifically, the perforation 221 arranged on the second bottom wall 224 is a through hole that connects the second microchannel 220 with the first microchannel 231, so as to be used as a nozzle for jet impact. The shape of the through hole can be selected as needed, for example, a through hole with a circular, square or triangular cross-section. Preferably, the cross-section of the through hole is circular to reduce the resistance of the through hole to the refrigerant and reduce the residue of the refrigerant on the through hole.

[0063] As one of the preferred embodiments of the heat dissipation body 20, Figures 1 to 4 As shown, the heat dissipation body 20 includes a detachably connected jet plate 22 and a microchannel heat exchange plate 23; the microchannel unit 230 is arranged on the microchannel heat exchange plate 23; and the jet unit is arranged on the jet plate 22. This facilitates the processing of the microchannel unit 230 and the jet unit. Specifically, as Figures 2 to 6 As shown, the microchannel heat exchange plate 23 is a box-shaped structure formed by the first outer plate 236 and the first bottom side plate, and has a first accommodating cavity and an upper opening connecting the first accommodating cavity with the outside. The first side wall 233 or the second side wall 238 of the first microchannel 231 located on the outermost side constitutes at least a part of the first outer plate 236, and the first bottom wall 234 constitutes at least a part of the first bottom side plate. The microchannel unit 230 is arranged in the first accommodating cavity of the microchannel heat exchange plate 23, and the partition arranged in the first accommodating cavity divides the first accommodating cavity into a plurality of first microchannels 231. When the microchannel heat exchange plate 23 also has a fluid collection cavity, at least one end of at least a part of the partition constituting the microchannel unit 230 is not connected to at least one side wall of the microchannel heat exchange plate 23, so that at least a part of the fluid collection cavity connected to the microchannel unit 230 is enclosed at least one end of the microchannel unit 230 by the first outer plate 236, the first bottom side plate and the partition of the microchannel heat exchange plate 23. As shown Figure 2 , Figure 3 , Figure 4 , Figure 8 and Fig. 9As shown, the jet plate 22 is a boxed structure formed by the second outer plate 226 and the second bottom plate, which has a second accommodating cavity and an upper opening that connects the second accommodating cavity to the outside. The guide rib 223 of the second microchannel 220 located at the outermost side constitutes at least a part of the second outer plate 226, and the second bottom wall 224 constitutes at least a part of the second bottom plate. The second microchannel 220 is arranged in the second accommodating cavity of the jet plate 22. Exemplarily, several second microchannels 220 are separated in the second accommodating cavity by the guide rib 223 arranged in the second accommodating cavity. When the jet plate 22 also has a partial fluid collection cavity, a first inner plate 227 is also arranged inside the second accommodating cavity of the jet plate 22 to separate the guide rib 223 forming the second microchannel 220 from the second outer plate 226 located at the end of the guide rib 223, so as to enclose the part of the fluid collection cavity by the first inner plate 227 and the second outer plate 226.

[0064] Preferably, Figures 1 to 4 As shown, the heat dissipation body 20 also includes a cover plate 21 detachably connected to the jet plate 22; the cover plate 21, the jet plate 22 and the microchannel heat exchange plate 23 are arranged in sequence from top to bottom; the fluid collection chamber includes a first collection chamber 235 provided on the microchannel heat exchange plate 23, and a second collection chamber 225 provided on the jet plate 22 and connected to the first collection chamber 235, the first collection chamber 235 is a part of the fluid collection chamber in the aforementioned microchannel heat exchange plate 23, and the second collection chamber 225 is a part of the fluid collection chamber in the aforementioned jet plate 22, which will not be repeated here; the second collection chamber 225 is connected to the outside through a first outlet 211 provided on the cover plate 21. When the heat dissipation body 20 is used, the refrigerant is injected into the second microchannel 220 from the first inlet 222, and the refrigerant in the second microchannel 220 is injected into the first microchannel 231 through the perforation 221; then, the refrigerant in the first microchannel 231 flows through the first collection cavity 235 and the second collection cavity 225 in sequence, and then flows out of the heat dissipation body 20 from the first outlet 211, completing the heat exchange process. The present invention achieves the purpose of fully utilizing the refrigerant by arranging the first collection cavity 235 at the lower part of the second collection cavity 225 and the second collection cavity 225 at the lower part of the first outlet 211, thereby increasing the time for the refrigerant to flow out of the system.

[0065] In the present invention, connection or installation is a fixed connection unless otherwise specified. Fixed connection can be implemented as a detachable connection or a non-detachable connection commonly used in the prior art. The detachable connection can be implemented by the prior art, such as threaded connection or key connection. The non-detachable connection can also be implemented by the prior art, such as welding or gluing.

[0066] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. Microchannel phase change heat transfer system, characterized in that: It includes a heat dissipation body (20); The heat dissipation body (20) has a microchannel unit (230), wherein a bubbling structure is provided in the microchannel unit (230), wherein the microchannel unit (230) comprises at least two first microchannels (231) arranged in parallel, and wherein the bubbling structure is a recessed structure provided on a wall surface of the first microchannel (231); The recessed structure is a cavity (232) or a groove (237). The wall surface of the first microfluidic channel (231) comprises a first bottom wall (234) located at the bottom of the first microfluidic channel (231) and a first side wall (233) and a second side wall (238) located at the side of the first microfluidic channel (231) and arranged opposite to each other; the recessed structures on the first bottom wall (234), the first side wall (233) and the second side wall (238) of the same first microfluidic channel (231) are arranged alternately along the length direction of the first microfluidic channel; The heat dissipation body (20) further comprises a jet unit for adding a jet into the microchannel unit (230), wherein the jet unit comprises perforations (221) arranged along the length direction of the first microchannel (231); The heat dissipation body (20) also has a fluid distribution cavity for evenly distributing the cooling medium into each first micro-channel (231); The heat dissipation body (20) also has a first inlet (222) for connecting the fluid distribution chamber with the outside; The fluid distribution chamber for uniformly distributing the refrigerant to each first microchannel (231) is implemented as follows: the heat dissipation body (20) also has a second microchannel (220) surrounded by a guide rib (223) and a second bottom wall (224), which corresponds one-to-one to the first microchannel (231); the second microchannel (220) is connected to the first microchannel (231) via a perforation (221) provided on the second bottom wall (224); the first inlet (222) is provided on one of the outermost guide ribs (223); and the height of the guide rib (223) increases as the distance between the guide rib and the first inlet (222) increases.

2. The microchannel phase change heat transfer system according to claim 1, characterized in that: The recessed structures on at least one of the first bottom wall (234), the first side wall (233) and the second side wall (238) are distributed at equal intervals.

3. The microchannel phase change heat transfer system according to claim 2, characterized in that: The distance between two adjacent recessed structures arranged on the first side wall (233) and the second side wall (238) is twice the distance between two adjacent recessed structures arranged on the first bottom wall (234).

4. The microchannel phase change heat transfer system according to claim 3, characterized in that: The distance between the recessed structures arranged on the first side wall (233) and the second side wall (238) is equal to the distance between two adjacent recessed structures arranged on the first bottom wall (234).

5. The microchannel phase change heat transfer system according to claim 1, characterized in that: The perforation (221) is located above the first microchannel (231); Furthermore, the perforations (221) and the recessed structures on the first bottom wall (234) are arranged in an alternating manner, and / or the perforations (221) and the recessed structures on the first side wall (233) and the second side wall (238) are arranged correspondingly along the length direction of the first microchannel (231).

6. The microchannel phase change heat transfer system according to claim 5, characterized in that: The recessed structure provided on the first side wall (233) and the second side wall (238) is a groove (237), and the groove (237) is arranged along the vertical direction; the recessed structure provided on the first bottom wall (234) is a cavity (232).

7. The microchannel phase change heat transfer system according to any one of claims 1 to 6, characterized in that: At least a portion of the surface of the recessed structure is configured as a super-hydrophobic surface; At least part of the inner surface of the first microchannel (231) other than the recessed structure is configured as a super-hydrophilic surface.

8. The microchannel phase change heat transfer system according to any one of claims 1 to 6, characterized in that: The heat dissipation body (20) also has a fluid collection cavity, and the first microchannel (231) is connected to the outside through the fluid collection cavity.

9. The microchannel phase change heat transfer system according to claim 8, characterized in that: The fluid collection chamber is arranged at both ends of the first microchannel (231) in the length direction.

10. The microchannel phase change heat transfer system according to claim 7, characterized in that: The heat dissipation body (20) also has a fluid collection cavity, and the first microchannel (231) is connected to the outside through the fluid collection cavity.

11. The microchannel phase change heat transfer system according to claim 10, characterized in that: The fluid collection chamber is arranged at both ends of the first microchannel (231) in the length direction.

12. The microchannel phase change heat transfer system according to any one of claims 1 to 6, characterized in that: The heat dissipation body (20) comprises a detachably connected jet plate (22) and a microchannel heat exchange plate (23); The microchannel unit (230) is arranged on the microchannel heat exchange plate (23); The jet unit is arranged on the jet plate (22).

13. The microchannel phase change heat transfer system according to claim 7, characterized in that: The heat dissipation body (20) comprises a detachably connected jet plate (22) and a microchannel heat exchange plate (23); The microchannel unit (230) is arranged on the microchannel heat exchange plate (23); The jet unit is arranged on the jet plate (22).

14. The microchannel phase change heat transfer system according to claim 8, characterized in that: The heat dissipation body (20) comprises a detachably connected jet plate (22) and a microchannel heat exchange plate (23); The microchannel unit (230) is arranged on the microchannel heat exchange plate (23); The jet unit is arranged on the jet plate (22).

15. The microchannel phase change heat transfer system according to claim 9, characterized in that: The heat dissipation body (20) comprises a detachably connected jet plate (22) and a microchannel heat exchange plate (23); The microchannel unit (230) is arranged on the microchannel heat exchange plate (23); The jet unit is arranged on the jet plate (22).

16. The microchannel phase change heat transfer system according to claim 10, characterized in that: The heat dissipation body (20) comprises a detachably connected jet plate (22) and a microchannel heat exchange plate (23); The microchannel unit (230) is arranged on the microchannel heat exchange plate (23); The jet unit is arranged on the jet plate (22).

17. The microchannel phase change heat transfer system according to claim 11, characterized in that: The heat dissipation body (20) comprises a detachably connected jet plate (22) and a microchannel heat exchange plate (23); The microchannel unit (230) is arranged on the microchannel heat exchange plate (23); The jet unit is arranged on the jet plate (22).

18. The microchannel phase change heat transfer system according to claim 14, characterized in that: The heat dissipation body (20) further comprises a cover plate (21) detachably connected to the jet plate (22); The cover plate (21), the jet plate (22) and the microchannel heat exchange plate (23) are arranged in sequence from top to bottom; The fluid collecting chamber comprises a first collecting chamber (235) provided on the microchannel heat exchange plate (23), and a second collecting chamber (225) provided on the jet plate (22) and communicating with the first collecting chamber (235); The second collecting chamber (225) is in communication with the outside via a first outlet (211) provided on the cover plate (21).

19. The microchannel phase change heat transfer system according to claim 15, characterized in that: The heat dissipation body (20) further comprises a cover plate (21) detachably connected to the jet plate (22); The cover plate (21), the jet plate (22) and the microchannel heat exchange plate (23) are arranged in sequence from top to bottom; The fluid collecting chamber comprises a first collecting chamber (235) provided on the microchannel heat exchange plate (23), and a second collecting chamber (225) provided on the jet plate (22) and communicating with the first collecting chamber (235); The second collecting chamber (225) is in communication with the outside via a first outlet (211) provided on the cover plate (21).

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