CN212253778U - Vapor chamber - Google Patents
Vapor chamber Download PDFInfo
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- CN212253778U CN212253778U CN202020460212.9U CN202020460212U CN212253778U CN 212253778 U CN212253778 U CN 212253778U CN 202020460212 U CN202020460212 U CN 202020460212U CN 212253778 U CN212253778 U CN 212253778U
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Abstract
The utility model discloses a vapor chamber. The thermal cycle efficiency of the existing vacuum soaking plate needs to be improved. The utility model comprises a cover plate and a bottom plate which are fixed together, and a sealed vacuum cavity is formed between the bottom plate and the cover plate; a phase change heat transfer working medium is arranged in the vacuum cavity; the inner surface of the cover plate is provided with an array type curved surface groove, and the inner surface of the cover plate is provided with a super-hydrophobic coating; the inner surface of the bottom plate is provided with a porous water absorbing medium; the array type curved surface groove comprises a plurality of notches which are arranged in an array manner; the side wall of the notch is an inclined plane or a curved surface, and the cross sectional area of the bottom of the notch is smaller than that of the top. The utility model discloses utilize working medium liquid at the induced self-propelled modal motion of the merge on super hydrophobic coating surface and its polymerization at the action of gravity on array curved surface slot surface, the steam condensation on super hydrophobic coating surface assembles the process with higher speed, has improved the whole heat transfer efficiency of vacuum cavity soaking plate.
Description
Technical Field
The utility model relates to an electronic product heat dissipation technology especially relates to a novel vacuum cavity soaking plate.
Background
With the rapid development of modern electronic technology, various electronic components are developed towards high efficiency and miniaturization, the internal space of electronic equipment is smaller and smaller, and the distribution is denser and denser, so that internal heating is concentrated, and the heat flux density is too high. The high heat generation amount can cause the performance of the electronic element to be reduced, and even the failure of the element can occur when the temperature exceeds a certain range. The high-density heat flow can form hot spots on the surface of the component, the performance of the component is influenced, the reliability of the whole system is further influenced, data show that when the working temperature of a CPU exceeds the rated working temperature by 10 ℃, the reliability of the CPU is reduced by 50%, and the thermal stress generated by high temperature is more likely to cause the damage of the component structure. Therefore, the improvement of the heat dissipation capacity in the electrical components has great promotion effect on the progress of the electronic technology.
The usual way of heat dissipation is to transport the concentrated heat flow to a larger plane and then transfer the heat to air (air cooling) or liquid (water cooling) by means of forced convection heat transfer. At present, phase change heat transfer is taken as efficient convection heat transfer (the heat transfer coefficient reaches 5000W/(m)2K) ordinary convective heat transfer coefficient of less than 1000W/(m)2K)), the advantages are significant. The heat pipe is the most typical phase change heat transfer element, becomes the mainstream scheme of heat dissipation of high-performance electronic components, and is widely applied to the fields of electronic information, aerospace and the like.
When the heat pipe works, heat flow of a heat source is transferred from the evaporation end to the condensation end, then from the condensation end to the heat sink with a large area in a heat conduction mode, and finally the heat is taken away in a heat convection mode. Due to the shape limitation of the heat pipe, the heat pipe mainly realizes the one-dimensional heat transfer from a heat source to a heat sink. In most electronic components, heat transfer in two-dimensional and three-dimensional planes is common, and vacuum vapor chambers are produced accordingly. The vacuum soaking plate can rapidly transfer and diffuse heat flow gathered on the surface of a heat source to a large-area condensation surface, so that heat dissipation is promoted, the heat flow density on the surface of a component is reduced, and reliable work of the component is guaranteed.
The traditional vacuum cavity vapor chamber is usually arranged between an electronic component and a radiator, the bottom of the vapor chamber is a heated layer which is adhered to the surface of the component, and the phase change of working media inside the vapor chamber and the auxiliary action of gravity are utilized to realize the rapid heat transfer. When the soaking plate works, heat on the surface of a heat source is transferred to the evaporation end through heat conduction, the working medium in the soaking plate absorbs latent heat and evaporates, the whole vacuum cavity is filled with working medium steam, the working medium steam moves to the condensation end to release the latent heat and is condensed into liquid, the condensed liquid passes through the liquid absorption core and finally returns to the bottom evaporation end under the action of capillary pressure and gravity, and liquid circulation is added again. However, the current vacuum vapor chamber needs to be provided with a water storage layer, porous materials of the water storage layer mainly adopt sintered copper powder, the working medium only depends on the action of a liquid suction core in a backflow mode, the circulation mode is single, and the capillary limit and the boiling limit range of heat exchange are small.
Therefore, a novel vapor chamber is needed to be provided, so that the reflux speed of condensed liquid drops is accelerated, the heat circulation efficiency in the vacuum chamber is improved, and the heat dissipation effect of the vapor chamber is enhanced.
Disclosure of Invention
In order to overcome the technical defect, the utility model aims to provide a novel vacuum cavity soaking plate promotes the inside thermal cycle of vacuum cavity soaking plate to flow and accelerate, strengthens its condensation and the recovery ability to the working medium, improves the inside heat transfer efficiency of soaking plate, increases the soaking plate heat transfer limit.
The utility model adopts the technical scheme as follows:
the utility model comprises a cover plate and a bottom plate which are fixed together, and a sealed vacuum cavity is formed between the bottom plate and the cover plate; a phase change heat transfer working medium is arranged in the vacuum cavity; the inner surface of the cover plate is provided with an array type curved surface groove, and the inner surface of the cover plate is provided with a super-hydrophobic coating; the inner surface of the bottom plate is provided with a porous water absorbing medium; the array type curved surface groove comprises a plurality of notches which are arranged in an array manner; the side wall of the notch is an inclined plane or a curved surface, and the cross sectional area of the bottom of the notch is smaller than that of the top.
Further, the height of the vacuum cavity is 2-4 mm.
Furthermore, the thickness of the cover plate and the bottom plate is 0.5-1 mm.
Further, the liquid filling rate of the phase-change heat transfer medium in the vacuum cavity is 40-60%.
Furthermore, the notch is in a regular quadrangular frustum pyramid shape, a regular triangular pyramid shape, a hemisphere shape or a cone shape.
Furthermore, the micro-nano structure of the super-hydrophobic coating on the inner surface of the cover plate is a secondary structure, and the characteristic dimension is 0.1-10 mu m.
Further, an apparent static contact angle of a liquid droplet formed at the superhydrophobic coating with the superhydrophobic coating is greater than or equal to 120 °.
Further, the porous water absorbing medium is formed by sintering copper powder, and the average grain diameter of the copper powder is less than 60 mu m.
Furthermore, the cover plate and the bottom plate are made of copper.
Furthermore, the phase-change heat transfer working medium is a unitary fluid or a multi-component fluid. The unitary fluid is deionized water, acetone, methanol or ethanol, and the multi-component fluid is a mixed solution of deionized water and ethanol, a mixed solution of deionized water and propylene glycol or a mixed solution of deionized water, ethylene glycol and octanol; the multi-component fluid has different contents of each component.
The utility model has the advantages that:
1. the utility model discloses utilize working medium liquid at the induced self-propelled modal motion of the merge on super hydrophobic coating surface and its polymerization at the action of gravity on array curved surface slot surface, the steam condensation on super hydrophobic coating surface assembles the process with higher speed, has improved the whole heat transfer efficiency of vacuum cavity soaking plate. The liquid drops are condensed on the surface of the super-hydrophobic coating, and then approach and contact with surrounding liquid drops to be merged into one liquid drop, extra surface energy is released due to the fact that the whole surface area of the merged liquid drop is reduced, and a part of surface energy is converted into kinetic energy of the merged liquid drop, so that the liquid drop generates self-propulsion bouncing movement without the help of external force and is accelerated to return to the water storage layer, the liquid drop is accelerated to return to the heated layer from the condensation layer, heat transfer is enhanced, and the temperature of the heated layer is reduced. In addition, the liquid drops after evaporation and condensation can be converged to corresponding convergence points along the inclined plane or the curved side wall of the array type curved groove by means of self gravity to form larger liquid drops, and the array type curved groove accelerates the merging process of the liquid drops and induces bouncing and backflow, so that the process of returning the liquid drops to the water storage layer is accelerated, the phase change circulation in the vacuum cavity is enhanced, and the heat transfer efficiency is improved. If no array type curved surface groove is arranged, when the surface heat flow of the condensation end is large, the formation and combination process of the condensed liquid drops is hindered to a certain extent, and the self-propulsion bouncing and the return of the liquid drops to the heated area are further influenced.
2. The utility model discloses super hydrophobic coating's micro-nano structure is secondary structure (Two-tier), can utilize micro-nano structure's geometry (plane or hilly form) nature and distribution (position or sparse degree) characteristic change to control super hydrophobic coating surface heat transfer performance height, the circulation flow rate of reinforcing liquid drop.
Drawings
FIG. 1 is a sectional view of the vapor chamber of the present invention;
FIG. 2 is a schematic view of a superhydrophobic coating and droplets on the surface thereof according to the present invention;
fig. 3(a), fig. 3(b), fig. 3(c) and fig. 3(d) are schematic structural diagrams of the cover plate when the notch is adopted to be the regular quadrangular frustum pyramid, the regular triangular pyramid, the hemisphere and the conical array-type curved groove, respectively.
Detailed Description
The present invention will be further explained with reference to the accompanying drawings.
As shown in fig. 1, a vapor chamber comprises a cover plate 1 and a bottom plate 3 fixed together, a sealed vacuum chamber 2 is formed between the bottom plate 3 and the cover plate 1; a phase change heat transfer working medium 11 is arranged in the vacuum cavity 2; the inner surface of the cover plate 1 is provided with an array type curved groove 4 (as shown in fig. 3(a), fig. 3(b), fig. 3(c) and fig. 3 (d)), and the inner surface of the cover plate is provided with a super-hydrophobic coating 5; the inner surface of the cover plate 1 is used as a condensation layer 10; the bottom plate 3 is adhered to the surface of the electronic component; the base plate 3 serves as a heat receiving layer 7; the inner surface of the bottom plate 3 is provided with a porous water-absorbing medium 6 which has higher hydrophilicity and forms a super-hydrophilic surface; the area where the porous water-absorbing medium 6 is located is used as a water storage layer 8; the space between the water storage layer 8 and the condensation layer 10 is an evaporation layer 9.
The super-hydrophobic coating on the inner surface of the cover plate 1 has a micro-nano structure, and the micro-nano structure is kept unchanged by means of solid particle consolidation. The micro-nano structure is a secondary structure (Two-tier), namely a structure of a carbon nano tube is also contained in the micro-column.
The porous water absorbing medium 6 is formed by sintering copper powder, and the average grain diameter of the copper powder is less than 60 mu m. The super-hydrophilic structure of the porous water-absorbing medium 6 can enhance the capillary force on the phase-change heat transfer working medium and improve the absorption rate on the backflow phase-change heat transfer working medium.
The cover plate 1 and the bottom plate 3 are made of copper.
The phase-change heat transfer working medium is a unitary fluid or a multi-component fluid. The monobasic fluid can be deionized water, acetone, methanol or ethanol, the polybasic fluid can be a mixed solution of deionized water and ethanol, a mixed solution of deionized water and propylene glycol or a mixed solution of deionized water, ethylene glycol and octanol, and the contents of all components in the polybasic fluid are different. The phase-change heat transfer working medium has a higher quality factor (Figure of merit) under most working conditions, and is beneficial to improving the performance of the soaking plate. The liquid filling rate of the phase change heat transfer medium in the vacuum cavity is 40-60%, and the vacuum cavity 2 can be kept in a state close to vacuum at normal temperature.
As shown in fig. 2, in the present embodiment, deionized water is used as the phase-change heat transfer working medium, and after the super-hydrophobic coating 5 is processed on the inner surface of the cover plate, the apparent static contact angle between the deionized water droplet formed at the super-hydrophobic coating 5 and the super-hydrophobic coating is about 120 °, which is because the diameter of the deionized water droplet formed at the super-hydrophobic coating 5 in the present embodiment is about 100 μm, the volume is relatively large, and the contact angle is small due to the influence of gravity; when the phase-change heat transfer working medium adopts other unitary fluid or multi-component fluid, the size of a condensed liquid drop formed at the super-hydrophobic coating 5 after evaporation is smaller than that in the embodiment (the variation range is generally 10-102 mu m) in a stable state in the actual working process of the vapor chamber, and correspondingly, the static contact angle between the condensed liquid drop and the super-hydrophobic coating is larger (the variation range is generally 150-180 degrees), so that the super-hydrophobic state can be fully achieved.
As shown in fig. 3(a), 3(b), 3(c) and 3(d), the array-type curved groove 4 includes a plurality of notches arranged in an array; the side wall of the notch is an inclined plane or a curved surface, and the cross sectional area of the bottom of the notch is smaller than that of the top; the notch is in a regular quadrangular frustum pyramid shape, a regular triangular pyramid shape, a hemisphere shape or a cone shape. The phase-change heat transfer working medium liquid drops are evaporated and condensed on the surface of the super-hydrophobic coating of the cover plate 1, and the plurality of liquid drops after evaporation and condensation are converged into the notch along the side wall of the notch under the action of gravity, so that merging induction of the liquid drops is realized, and self-bouncing behavior is completed.
The formation of the vacuum chamber between the base plate 3 and the cover plate 1 is as follows:
after two through holes are formed in two sides of the cover plate 1, the cover plate 1 and the bottom plate 3 are fixed; then, two through holes positioned on different sides are respectively communicated with two metal pipelines, one metal pipeline is connected with a vacuum pump through a connecting pipe, the other metal pipeline is connected with one port of a three-way control valve through a connecting pipe, and the other two ports of the three-way control valve are respectively connected with an injector and a vacuum pressure gauge through connecting pipes; the three-way control valve is firstly controlled to be communicated with the injector and a cavity between the bottom plate 3 and the cover plate 1, and liquid is injected into the cavity between the bottom plate 3 and the cover plate 1 through the injector. After the injection amount reaches the set phase change heat transfer working medium liquid filling rate, controlling a three-way control valve to communicate a vacuum pressure gauge and a cavity between the plate 3 and the cover plate 1; and then, starting a vacuum pump, starting to extract air in the cavity between the bottom plate 3 and the cover plate 1, closing the vacuum pump when the reading of a vacuum pressure gauge reaches-0.08 MPa, sealing the metal pipeline connected with the vacuum pump on the cover plate 1, and removing the vacuum pump. Then, the bottom plate 3 is heated through a heat source, and the bottom plate 3 is radiated by a radiator, so that the pressure in the cavity between the bottom plate 3 and the cover plate 1 is fed back and adjusted, when the pressure in the cavity between the bottom plate 3 and the cover plate 1 reaches the critical gas-liquid phase change pressure of the phase change heat transfer working medium, the heating is stopped, and at the moment, gas (such as nitrogen and the like) in the cavity between the bottom plate 3 and the cover plate 1 is extruded into a connecting pipe connecting a metal pipeline and a three-way control valve; finally, the metal pipeline connected with the three-way control valve on the cover plate 1 is sealed, then the three-way control valve, the vacuum pressure gauge and the injector are removed, and the unused gas extruded into the connecting pipe connected with the three-way control valve is discharged out of the cavity between the bottom plate 3 and the cover plate 1. At this time, the cavity between the base plate 3 and the cover plate 1 is regarded as being in a vacuum state, forming a vacuum chamber.
Different geometric properties and distribution characteristics of the super-hydrophobic coating can be arranged on the cover plates 1, then the cover plates and the bottom plate are fixed, and the bottom plate 3 is adhered to the electronic component for heat dissipation experiments; in the experimental process, the heat dissipation efficiency is obtained by measuring the surface temperature distribution condition of the bottom plate 3, and the geometric properties and the distribution characteristics of the super-hydrophobic coating of the vapor chamber with high heat dissipation efficiency are obtained; certainly, in order to further verify the enhanced heat transfer effect that adopts super hydrophobic coating and array curved surface slot, the vacuum cavity soaking plate that does not have super hydrophobic coating and array curved surface slot, the vacuum cavity soaking plate that has super hydrophobic coating and does not have array curved surface slot, the three contrast group of vacuum cavity soaking plate that does not have super hydrophobic coating and array curved surface slot is tested, three contrast group obtains the radiating efficiency through measuring bottom plate 3's surface temperature distribution condition equally, and heat source input power all with the utility model discloses heat source input power is unanimous during the vacuum cavity soaking plate experiment of three contrast group, just can obviously find out the enhanced heat transfer effect that adopts super hydrophobic coating and array curved surface slot from the contrast experiment.
The working principle of the vapor chamber is as follows:
adhering the base plate 3 to the surface of an electronic component (such as a CPU); when the electronic component generates heat, the bottom of the bottom plate is heated, the liquid phase-change heat transfer working medium in the porous water absorption medium 6 is heated and evaporated to reach the evaporation layer 9, the liquid phase-change heat transfer working medium rises to the top of the vacuum cavity 2 in the vacuum cavity 2 and reaches the condensation layer 10 of the cover plate 1, the surface of the condensation layer 10 is a super-hydrophobic coating, the phase-change heat transfer working medium steam is condensed into phase-change heat transfer working medium droplets in the super-hydrophobic coating, and each phase-change heat transfer working medium droplet is accelerated to polymerize with the surrounding phase-change heat transfer working medium droplets through the inclined surface or the curved surface side wall of the; after polymerization, the liquid drops with the gravity greater than the adhesion force are separated from the cover plate 1 and accelerated back to the porous water absorbing medium 6 under the action of gravity, so that the heat transfer cycle process is completed.
Claims (9)
1. A vapor chamber comprises a cover plate and a bottom plate which are fixed together, wherein a sealed vacuum chamber is formed between the bottom plate and the cover plate; a phase change heat transfer working medium is arranged in the vacuum cavity; the method is characterized in that: the inner surface of the cover plate is provided with an array type curved surface groove, and the inner surface of the cover plate is provided with a super-hydrophobic coating; the inner surface of the bottom plate is provided with a porous water absorbing medium; the array type curved surface groove comprises a plurality of notches which are arranged in an array manner; the side wall of the notch is an inclined plane or a curved surface, and the cross sectional area of the bottom of the notch is smaller than that of the top.
2. A vapor chamber in a vacuum chamber according to claim 1, wherein: the height of the vacuum cavity is 2-4 mm.
3. A vapor chamber in a vacuum chamber according to claim 1, wherein: the thickness of the cover plate and the bottom plate is 0.5-1 mm.
4. A vapor chamber in a vacuum chamber according to claim 1, wherein: the liquid filling rate of the phase-change heat transfer medium in the vacuum cavity is 40-60%.
5. A vapor chamber in a vacuum chamber according to claim 1, wherein: the notch is in a regular quadrangular frustum pyramid shape, a regular triangular pyramid shape, a hemisphere shape or a cone shape.
6. A vapor chamber in a vacuum chamber according to claim 1, wherein: the micro-nano structure of the super-hydrophobic coating on the inner surface of the cover plate is a secondary structure, and the characteristic dimension is 0.1-10 mu m.
7. A vapor chamber in a vacuum chamber according to claim 1, wherein: an apparent static contact angle of a liquid drop formed at the superhydrophobic coating with the superhydrophobic coating is greater than or equal to 120 °.
8. A vapor chamber in a vacuum chamber according to claim 1, wherein: the porous water absorbing medium is formed by sintering copper powder, and the average grain diameter of the copper powder is less than 60 mu m.
9. A vapor chamber in a vacuum chamber according to claim 1, wherein: the cover plate and the bottom plate are made of copper.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020460212.9U CN212253778U (en) | 2020-04-01 | 2020-04-01 | Vapor chamber |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020460212.9U CN212253778U (en) | 2020-04-01 | 2020-04-01 | Vapor chamber |
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| CN212253778U true CN212253778U (en) | 2020-12-29 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114234689A (en) * | 2021-11-25 | 2022-03-25 | 苏州浪潮智能科技有限公司 | Enhanced boiling heat exchange structure and temperature-equalizing plate |
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2020
- 2020-04-01 CN CN202020460212.9U patent/CN212253778U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114234689A (en) * | 2021-11-25 | 2022-03-25 | 苏州浪潮智能科技有限公司 | Enhanced boiling heat exchange structure and temperature-equalizing plate |
| CN114234689B (en) * | 2021-11-25 | 2023-09-01 | 苏州浪潮智能科技有限公司 | Enhanced boiling heat exchange structure and temperature equalization plate |
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