CN115348805A - Gradual-change type liquid absorption core flat micro heat pipe and preparation method thereof - Google Patents
Gradual-change type liquid absorption core flat micro heat pipe and preparation method thereof Download PDFInfo
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- CN115348805A CN115348805A CN202210982039.2A CN202210982039A CN115348805A CN 115348805 A CN115348805 A CN 115348805A CN 202210982039 A CN202210982039 A CN 202210982039A CN 115348805 A CN115348805 A CN 115348805A
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- 239000007788 liquid Substances 0.000 title claims abstract description 108
- 238000010521 absorption reaction Methods 0.000 title claims abstract description 75
- 238000002360 preparation method Methods 0.000 title abstract description 6
- 239000002245 particle Substances 0.000 claims abstract description 61
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 52
- 238000001704 evaporation Methods 0.000 claims abstract description 51
- 230000008020 evaporation Effects 0.000 claims abstract description 51
- 238000009833 condensation Methods 0.000 claims abstract description 41
- 230000005494 condensation Effects 0.000 claims abstract description 41
- 238000005245 sintering Methods 0.000 claims abstract description 33
- 238000013461 design Methods 0.000 claims abstract description 9
- 230000008595 infiltration Effects 0.000 claims abstract description 6
- 238000001764 infiltration Methods 0.000 claims abstract description 6
- 238000009736 wetting Methods 0.000 claims abstract description 5
- 238000003486 chemical etching Methods 0.000 claims abstract description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 27
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 22
- 238000009413 insulation Methods 0.000 claims description 20
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 18
- 239000000243 solution Substances 0.000 claims description 16
- 230000008859 change Effects 0.000 claims description 13
- 238000001035 drying Methods 0.000 claims description 11
- 229910001870 ammonium persulfate Inorganic materials 0.000 claims description 9
- 239000008367 deionised water Substances 0.000 claims description 8
- 229910021641 deionized water Inorganic materials 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 239000011521 glass Substances 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- 229910002804 graphite Inorganic materials 0.000 claims description 5
- 239000010439 graphite Substances 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 5
- 239000003292 glue Substances 0.000 claims description 4
- 238000005406 washing Methods 0.000 claims description 4
- 238000004140 cleaning Methods 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000011259 mixed solution Substances 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 3
- 238000005266 casting Methods 0.000 claims description 2
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 238000003825 pressing Methods 0.000 claims description 2
- 230000007423 decrease Effects 0.000 claims 1
- 238000012546 transfer Methods 0.000 abstract description 11
- 230000017525 heat dissipation Effects 0.000 abstract description 4
- 238000010992 reflux Methods 0.000 abstract description 4
- 235000019441 ethanol Nutrition 0.000 description 5
- 239000011148 porous material Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 239000011246 composite particle Substances 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000006210 lotion Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/2029—Modifications to facilitate cooling, ventilating, or heating using a liquid coolant with phase change in electronic enclosures
- H05K7/20336—Heat pipes, e.g. wicks or capillary pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
- F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
- F28D15/04—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure
- F28D15/046—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure characterised by the material or the construction of the capillary structure
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Cooling Or The Like Of Electrical Apparatus (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
The invention discloses a gradient type wick flat micro heat pipe and a preparation method thereof. The micro heat pipe is composed of an upper pipe shell, a lower pipe shell, a liquid absorption core and a liquid working medium, wherein the liquid absorption core is formed by sintering copper powder particles with different sizes in a layered and sectional manner and then performing chemical etching to form a surface with gradient infiltration. The thickness of the liquid absorption core is gradually reduced from the evaporation section to the condensation section, the width of the liquid absorption core is reduced in a trapezoidal shape, and the design increases the gas flowing space in the heat pipe. The liquid suction core is formed by sintering copper powder particles with different sizes in a layered mode, so that on one hand, liquid working medium permeation is facilitated, and on the other hand, the liquid reflux speed is increased. The liquid absorption core is in a gradient wetting surface after being chemically etched, and the acting force on the liquid working medium is increased, so that the flow velocity of the internal working medium is accelerated, and the evaporation section is not easy to burn out. The flat micro heat pipe has the advantages of simple structure, low thermal resistance, large heat transfer limit, good heat exchange performance and the like, and is suitable for heat dissipation of various electronic devices.
Description
Technical Field
The invention relates to the field of micro heat pipes, in particular to a gradient type liquid absorption core flat micro heat pipe and a preparation method thereof.
Background
Temperature is one of the important factors affecting the performance of electronic devices. The over-high temperature of the electronic equipment can cause the inherent characteristics of internal components to be completely changed and even burn out phenomenon occurs, thereby influencing the working state of the equipment. The traditional refrigeration mode has the problems of large volume, poor heat conduction performance, complex system structure and the like, and can not meet the heat dissipation requirements brought by high-speed development, high integration level and small size of electronic equipment. Therefore, the heat pipe with small shape and high heat dissipation rate can meet the requirement of long-time and high-power working environment of equipment.
The flat micro heat pipe is a component conducting heat based on the gas-liquid phase change principle. The liquid in the evaporation section in the heat pipe is heated and vaporized, the gaseous working medium is condensed into liquid in the condensation section to release heat, and the liquid working medium flows back to the heat source under the action of the capillary force of the capillary core. Therefore, ensuring smooth gas-liquid channels and increasing capillary force of the capillary core are key factors for improving the heat transfer performance of the flat micro heat pipe.
The heat pipe liquid absorption cores can be structurally divided into a groove type, a sintered wire mesh type, a sintered powder type and the like, wherein the copper powder sintered liquid absorption cores are widely applied to heat pipes due to good performance.
At present, copper powder sintered liquid absorption cores are mostly formed by sintering copper powder particles with single particle size or composite particle size. The pores of the liquid absorption core sintered by the copper powder particles with large particle size are relatively large, and the large pores can generate smaller friction resistance, so that the permeability is higher, and the effective capillary radius can be increased due to the high permeability, so that the capillary force is reduced, the capillary force is smaller, and the liquid cannot flow back to the vicinity of the evaporation section in time, so that the heat pipe is burnt dry. The effective capillary radius of the liquid absorption core sintered by the copper powder particles with the composite particle size is between the effective capillary radii of the liquid absorption cores sintered by the corresponding two copper powder particles with the single particle size, and the improvement on the overall heat transfer performance of the heat pipe is small.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a gradual change type liquid absorption core flat micro heat pipe and a preparation method thereof. The liquid absorption core structure provided by the invention ensures smooth circulation of a gas-liquid channel in the heat pipe, and the gradient infiltration structure provides larger capillary force, thereby effectively promoting the circulation speed of the liquid working medium. The technical problems that the existing copper powder type sintered liquid absorption core flat micro heat pipe is high in thermal resistance, slow in liquid backflow and blocked in a gas-liquid circulation channel are solved. The flat micro heat pipe has the advantages of simple structure, low thermal resistance, large heat transfer limit, good heat exchange performance and the like, and is suitable for heat dissipation of various electronic devices.
In order to solve the technical problem, the invention is realized by using the following technical scheme: the liquid absorption core is sequentially divided into an evaporation section, a heat insulation section and a condensation section, the width from the evaporation section to the condensation section is in a trapezoidal change, the surface area is gradually reduced, the thickness is gradually reduced, the volume of the evaporation section is larger than that of the heat insulation section and larger than that of the condensation section, and the liquid absorption core is formed by copper powder particles with different sizes through layered and segmented sintering and surface processing of forming gradient infiltration through chemical etching.
Preferably, the liquid absorption core is formed by layering, segmenting, tiling and sintering copper powder particles with different particle sizes, the evaporation segment is divided into two layers, the upper layer uses copper powder particles with the diameter of 180-200 micrometers, and the lower layer uses copper powder particles with the diameter of 120-140 micrometers; copper powder particles with the diameter of 160-180 microns are used for the heat insulation section; copper powder particles with a diameter of 170-190 microns are used in the condensation section.
Preferably, the thickness of the liquid absorption core is gradually reduced from 2-2.5mm of the top thickness of the evaporation section to 1-1.2mm of the tail end thickness of the condensation section; the width of the starting end of the evaporation section is 0.3-1.0mm longer than that of the tail end of the condensation section; the size lengths of the evaporation section, the heat insulation section and the condensation section of the heat pipe liquid absorption core are equal.
Preferably, the evaporation part of the liquid absorption core accounts for 45-50% of the volume of the evaporation section of the whole heat pipe; the heat insulation part of the liquid absorption core accounts for 30-35% of the volume of the heat insulation section of the whole heat pipe; the condensation part of the liquid absorption core accounts for 20-25% of the volume of the condensation section of the whole heat pipe.
Preferably, the surface of the liquid absorbing core is subjected to gradient wettability treatment, and the wetting angle of the surface of the liquid absorbing core is gradually increased from the evaporation section to the condensation section.
Preferably, the upper cover plate and the lower case are both made of copper.
On the other hand, the invention also provides a preparation method of the gradient type wick flat micro heat pipe, which comprises the following steps:
s1, taking out copper powder particles with different particle sizes, respectively placing the copper powder particles in ethanol for ultrasonic cleaning, then washing the copper powder particles with deionized water, sequentially paving the copper powder particles with the four different particle sizes in a graphite mold according to design requirements, and then placing the graphite mold into a vacuum sintering furnace for sintering;
s2, taking out the sintered and molded liquid absorption core, sequentially putting the liquid absorption core into an ethanol and deionized water solution for cleaning, and finally drying by using a drying oven;
s3, obliquely and vertically placing the liquid absorption core in a glass container to perform gradient infiltration treatment, placing the evaporation section of the liquid absorption core at the bottom of the container, gradually dropping the prepared mixed solution of sodium hydroxide and ammonium persulfate into the glass container in proportion, and completely immersing the solution in the upper edge of the condensation section of the liquid absorption core within 1 hour in the whole operation process;
s4, processing the designed upper cover plate and lower pipe shell by using a CNC (computerized numerical control) machine tool, then placing the processed upper cover plate and lower pipe shell into ethanol for ultrasonic cleaning, then washing by using deionized water, and finally placing in a drying box for drying;
s5, placing the liquid absorption core on the inner wall of the lower pipe shell, pressing the liquid absorption core by using a hot press, placing the liquid absorption core into a sintering furnace for integral sintering, then coating casting glue on the joint of the upper cover plate and the lower pipe shell, then clamping the liquid absorption core by using a clamp, after the glue is solidified, vacuumizing and injecting working medium from a small hole reserved in the upper cover plate, and finally sealing the small hole to obtain the flat micro heat pipe.
Preferably, the sintering temperature in S2 is 600-950 ℃, and the sintering time is 120-240 min.
Preferably, the concentration of sodium hydroxide in S3 is 0.8-1.2mol/L, and the concentration of ammonium persulfate in S3 is 0.08-0.12mol/L; the molar concentration ratio of the sodium hydroxide solution to the ammonium persulfate solution is 18-22:1.
compared with the prior art, the invention has the following beneficial effects: the width of the wick designed by the invention is gradually reduced from the evaporation section to the condensation section in a ladder shape, the surface area is gradually reduced, the thickness is gradually thinned, the wick evaporation section of the gradual change type structure has larger heat exchange area, a large amount of liquid working medium can be gathered at the evaporation section, the heat exchange limit of the heat pipe is improved, and the volume of the heat insulation section and the condensation section is gradually reduced, so that the airflow channel in the heat pipe is enlarged, and the gas flowing space in the heat pipe is increased.
The liquid absorption core designed by the invention is formed by sintering four copper powder particles with different particle sizes in a layered mode. The evaporation section is formed by sintering two layers of copper powder particles with different particle sizes, and the pore diameter of a liquid absorption core formed by sintering the upper layer of copper powder particles with large particle sizes is larger, so that the liquid working medium is favorably permeated; the effective radius of the liquid absorption core sintered by the lower layer of small-particle-size copper powder particles is small, so that larger capillary force is provided, and the liquid reflux speed is increased.
The invention forms gradient wettability on the surface of the liquid absorption core by a chemical etching method, the contact angle is gradually increased from the evaporation section to the condensation section of the heat pipe, and the acting force generated on the surface of the liquid absorption core is increased, thereby accelerating the reflux speed of the working medium liquid and improving the heat transfer performance of the heat pipe.
Drawings
FIG. 1 is a schematic view of a microthermal tube structure according to the present invention;
FIG. 2 is a schematic view of the position of the graded wick according to the present invention on the lower shell;
FIG. 3 is a schematic view of a graded wick according to the present invention;
FIG. 4 is a top view of a graded wick according to the present invention;
FIG. 5 is a side view of the profiled gradient imbibing fluid of the present invention;
FIG. 6 is a structural view of the shape of a lotion core in 4 different shapes;
FIG. 7 is a graph comparing thermal resistances of micro heat pipes with wicks of different shapes;
the labels in the figure are: 1-a gradual change type liquid absorption core, 2-an upper cover plate, 3-a lower pipe shell, 4-a condensation section, 5-a heat insulation section, 6-an upper evaporation section layer and 7-a lower evaporation section layer.
Detailed Description
The technical solutions of the present invention will be described in further detail with reference to the drawings and specific examples, but the present invention is not limited to the following technical solutions.
Example 1
As shown in fig. 1-5, the present embodiment provides a gradient wick flat micro heat pipe, which includes a gradient wick 1, an upper cover plate 2, a lower pipe shell 3 and a liquid working medium inside the heat pipe. The gradual-change type liquid absorption core 1 is formed by co-sintering copper powder particles in a condensation section 4, copper powder particles in a heat insulation section 5, copper powder particles in an upper layer 6 of an evaporation section and copper powder particles in a lower layer 7 of the evaporation section. The liquid absorption core 1 is placed in the middle of the lower pipe shell 3, the upper cover plate 2 and the lower pipe shell 3 are of a closed structure and made of copper, and liquid working media are injected into the lower pipe shell after the upper pipe shell is vacuumized and sealed.
The gradual change type liquid absorption core 1 is formed by sintering four copper powder particles with different sizes, the diameter of the copper powder particle in a condensation section 4 is 170-190 microns, preferably 180 microns, the diameter of the copper powder particle in a heat insulation section 5 is 160-180 microns, preferably 170 microns, the diameter of the copper powder particle in an upper layer 5 of an evaporation section is 180-200 microns, preferably 190 microns, and the diameter of the copper powder particle in a lower layer 7 of the evaporation section is 120-140 microns, preferably 130 microns; the layered design of the liquid absorption core meets the working requirements of all parts of the heat pipe, the pore diameter of the liquid absorption core section sintered by the copper powder particles with large particle size is larger, the liquid working medium is favorably permeated, the effective capillary radius of the liquid absorption core section sintered by the copper powder particles with small particle size is small, larger capillary force can be provided, the liquid reflux speed is improved, and therefore the heat transfer performance of the flat micro heat pipe is integrally improved.
The width of the liquid suction core is gradually reduced from the evaporation section to the condensation section in a trapezoidal manner, the surface area is gradually reduced, and the thickness is gradually reduced. This project organization makes the evaporation zone have great heat transfer area, makes a large amount of liquid working mediums assemble at the evaporation zone, improves the heat transfer limit of heat pipe, and adiabatic section and condensation segment volume reduce gradually, and this makes the air current passageway increase, has increased the inside gas flow space of heat pipe.
The liquid absorption core is subjected to gradient wettability treatment, and the surface wettability angle of the liquid absorption core is gradually increased from the evaporation section to the condensation section. The liquid absorption core is a gradient wetting surface, the acting force generated by the surface is increased, the flow speed of the liquid working medium in the liquid absorption core is increased, and compared with the liquid absorption core with a uniform surface contact angle, the flow speed of the fluid under the gradient wetting surface is higher. This makes the evaporation section not easy to generate the burning-out phenomenon, and improves the heat transfer limit of the heat pipe.
The evaporation part of the liquid absorption core accounts for 45-50% of the volume of the evaporation section of the whole micro heat pipe (the evaporation part of the liquid absorption core accounts for the whole cavity of the evaporation section of the micro heat pipe); the heat insulation part of the liquid absorption core accounts for 30-35% of the volume of the heat insulation section of the whole heat pipe; the condensation part of the liquid absorption core accounts for 20-25% of the volume of the condensation section of the whole heat pipe. The design provides sufficient space for the convergence of the liquid working medium at the evaporation section, the volume of the liquid working medium from the heat insulation section to the condensation section is gradually reduced, the airflow channel is enlarged, the gas flowing space in the heat pipe is increased, the gas-liquid circulation rate is integrally improved, and the heat transfer performance of the heat pipe is improved.
The size length ratio of the evaporation section to the heat insulation section to the condensation section of the heat pipe is 1, and the design provides longer length for the phase change part (evaporation and condensation), so that the contact area of the liquid working medium and the pipe wall is increased, the heat flux density is reduced, and the heat exchange performance of the flat micro heat pipe is improved.
Example 2
An upper cover plate 2 and a lower pipe shell 3 are machined according to the design size by using a CNC (computerized numerical control) machine tool, the upper cover plate 2 and the lower pipe shell 3 are sequentially cleaned for 5min by using methanol and ethanol in an ultrasonic mode, and tweezers are used in the whole operation process to contact the pipe shell.
Taking out copper powder particles with different purposes according to the design requirement of a liquid absorption core, respectively placing the copper powder particles in absolute ethyl alcohol (not less than 99,5%) for ultrasonic cleaning, then flushing the copper powder particles with deionized water, sequentially and sectionally paving the copper powder particles with four different particle sizes in a graphite mould according to the design requirement, and then placing the copper powder particles into a vacuum sintering furnace for sintering. The sintering temperature is 600-950 ℃, the sintering time is 120-240 min, the sintering temperature is preferably 700-950 ℃, and the sintering time is preferably 150-210min; and after the sintering is finished, taking out the liquid absorption core after the sintering furnace is cooled to room temperature. And (4) sequentially putting the liquid absorption core into an ethanol and deionized water solution for cleaning, and finally drying by using a drying oven.
And (2) obliquely placing the liquid absorption core in a glass container, gradually dropping the prepared mixed solution of sodium hydroxide and ammonium persulfate into the glass container in proportion, completely immersing the solution in the upper end of a condensation section of the liquid absorption core within 1 hour in the whole operation process, and placing the treated solution in a drying oven to obtain the liquid absorption core 1. The concentration of sodium hydroxide is 1.0mol/L, and the concentration of ammonium persulfate is 0.1mol/L; the molar concentration ratio of the sodium hydroxide solution to the ammonium persulfate solution is 20: about 1.
The wick 1 and the lower tube shell 3 are placed as shown in fig. 2, pressed by a hot press, and then integrally sintered in a sintering furnace, solder is applied to a welding band of the lower tube shell 3 and the upper cover plate 2, and the heat pipe is encapsulated on a heating plate at 200 ℃. Vacuumizing and injecting working medium from the small hole reserved in the upper tube shell, and finally sealing the small hole.
The flat micro heat pipe prepared by the steps is simple in process, and batch manufacturing of the flat micro heat pipe with the gradient type liquid absorption core can be achieved. The manufactured gradual change type liquid absorption core not only meets the working requirements of all parts of the heat pipe, but also increases the gas flowing space inside the heat pipe, accelerates the flow rate of liquid working medium, and the whole flat micro heat pipe shows excellent heat exchange performance in experiments.
The degree that the width and the thickness of the liquid suction core are gradually reduced in a trapezoidal manner from the evaporation section to the condensation section has great influence on heat exchange. This example produced wicks of 4 sizes, with the lengths of all four wicks, a, b, c and d (the size of the product of example 1) being 60mm, and the widths and heights of the evaporation and condensation sections of the four wicks being a (8mm x 2mm ), b (8mm x 2mm,6mm x 2mm), c (8mm x 2mm,5mm 2mm) and d (8mm x 2mm,5mm 1mm), respectively, as shown in figure 6.
The data of the heat transfer performance and thermal resistance experiment performed on the micro heat pipe corresponding to the four wicks is shown in fig. 7. As can be seen from the analysis in fig. 7, the heat resistance of the wick micro heat pipe of the present embodiment is significantly smaller than that of wick micro heat pipes of other shapes, and the heat exchange performance is significantly enhanced. Under the same heating power, the larger heat exchange area between the heat pipe and the outside means smaller heat flux density, and the smaller heat flux density causes the temperature difference in the heat pipe to change less, the temperature distribution to be more uniform, and therefore the thermal resistance is smaller.
The above embodiments are merely preferred examples, but the embodiments of the present invention are not limited by the above embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. The gradual change type wick flat micro heat pipe is characterized in that the wick is sequentially divided into an evaporation section, a heat insulation section and a condensation section, the width from the evaporation section to the condensation section is in a trapezoidal change, the surface area is gradually reduced, the thickness is gradually reduced, the volume of the evaporation section is larger than that of the heat insulation section and larger than that of the condensation section, and the wick is formed by sintering copper powder particles with different sizes in a layered and segmented manner and forming a surface with gradient infiltration through chemical etching.
2. The gradual change type wick flat micro heat pipe according to claim 1, wherein the wick is formed by layering, segmenting, tiling and sintering copper powder particles with different particle sizes, the evaporation segment is divided into two layers, the upper layer uses copper powder particles with the diameter of 180-200 microns, and the lower layer uses copper powder particles with the diameter of 120-140 microns; copper powder particles with the diameter of 160-180 microns are used for the heat insulation section; copper powder particles with a diameter of 170-190 microns are used in the condensation section.
3. The graded wick flat micro heat pipe according to claim 1, wherein the wick thickness gradually decreases from a thickness of 2-2.5mm at the top of the evaporation section to a thickness of 1-1.2mm at the end of the condensation section; the width of the starting end of the evaporation section is 0.3-1.0mm longer than that of the tail end of the condensation section; the size lengths of the evaporation section, the heat insulation section and the condensation section of the heat pipe liquid absorption core are equal.
4. The gradual wick flat micro heat pipe according to claim 1, wherein the wick evaporation part accounts for 45% -50% of the volume of the whole heat pipe evaporation section; the heat insulation part of the liquid absorption core accounts for 30-35% of the volume of the heat insulation section of the whole heat pipe; the condensation part of the liquid absorption core accounts for 20-25% of the volume of the condensation section of the whole heat pipe.
5. The graded wick flat micro heat pipe according to claim 1, wherein the wick surface is subjected to a gradient wettability treatment, and the wetting angle of the wick surface increases gradually from the evaporation section to the condensation section.
6. The graded wick flat micro heat pipe according to claim 1, wherein the upper cover plate and the lower pipe casing are both made of copper.
7. A method of making a graded-wick planar micro heat pipe according to any of claims 1 to 6, comprising the steps of:
s1, taking out copper powder particles with different particle sizes, respectively placing the copper powder particles in an ethanol solution for ultrasonic cleaning, then washing the copper powder particles with the deionized water, sequentially paving the copper powder particles with the four different particle sizes in a graphite mold according to design requirements, and then placing the graphite mold into a vacuum sintering furnace for sintering;
s2, taking out the sintered and formed liquid absorption core, sequentially putting the liquid absorption core into an ethanol and deionized water solution for cleaning, and finally drying by using a drying oven;
s3, obliquely and vertically placing the liquid absorption core in a glass container for gradient infiltration treatment, placing the evaporation section of the liquid absorption core at the bottom of the container, gradually dropping the prepared mixed solution of sodium hydroxide and ammonium persulfate into the glass container in proportion, and completely immersing the solution in the upper edge of the condensation section of the liquid absorption core within 1 hour in the whole operation process;
s4, processing the designed upper cover plate and lower tube shell by using a CNC (computerized numerical control) machine tool, then placing the processed upper cover plate and lower tube shell in ethanol for ultrasonic cleaning, then washing by using deionized water, and finally placing in a drying box for drying;
s5, placing the liquid absorption core on the inner wall of the lower pipe shell, pressing the liquid absorption core by using a hot press, placing the liquid absorption core into a sintering furnace for integral sintering, then coating casting glue on the joint of the upper cover plate and the lower pipe shell, then clamping the liquid absorption core by using a clamp, after the glue is solidified, vacuumizing and injecting working medium from a small hole reserved in the upper cover plate, and finally sealing the small hole to obtain the flat micro heat pipe.
8. The method for preparing a gradient wick flat micro heat pipe according to claim 7, wherein the sintering temperature in S2 is 600-950 ℃, and the sintering time is 120-240 min.
9. The method for preparing a gradual change wick flat micro heat pipe according to claim 7, wherein in S3, the concentration of sodium hydroxide is 0.8-1.2mol/L, and the concentration of ammonium persulfate is 0.08-0.12mol/L; the molar concentration ratio of the sodium hydroxide solution to the ammonium persulfate solution is 18-22:1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210982039.2A CN115348805B (en) | 2022-08-16 | 2022-08-16 | Gradual change type wick flat plate micro heat pipe and preparation method thereof |
Applications Claiming Priority (1)
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Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20010062646A (en) * | 1999-12-22 | 2001-07-07 | 오길록 | Heat pipe having a sintered wick structure and method for manufacturing the same |
| KR20060076831A (en) * | 2004-12-29 | 2006-07-05 | 유진컴텍(주) | Method of filling working fluid of heat pipe and appatatus thereof |
| TWI259264B (en) * | 2005-07-22 | 2006-08-01 | Forcecon Technology Co Ltd | Composite capillary structure of heat pipe |
| US20070095506A1 (en) * | 2005-10-20 | 2007-05-03 | Foxconn Technology Co., Ltd. | Heat pipe and method for making the same |
| US20070193722A1 (en) * | 2006-02-18 | 2007-08-23 | Foxconn Technology Co., Ltd. | Heat pipe with capillary wick |
| US20070204975A1 (en) * | 2006-03-03 | 2007-09-06 | Foxconn Technology Co., Ltd. | Heat pipe and method for manufacturing the same |
| US20070251673A1 (en) * | 2006-04-28 | 2007-11-01 | Foxconn Technology Co., Ltd. | Heat pipe with non-metallic type wick structure |
| US20100263833A1 (en) * | 2009-04-21 | 2010-10-21 | Yeh-Chiang Technology Corp. | Sintered heat pipe |
| DE202012008533U1 (en) * | 2012-09-03 | 2012-10-22 | Asia Vital Components Co., Ltd. | Heat pipe, cooling module and electronic connection |
| US20180313611A1 (en) * | 2015-12-28 | 2018-11-01 | Furukawa Electric Co., Ltd. | Heat pipe |
| CN110926247A (en) * | 2019-12-13 | 2020-03-27 | 大连理工大学 | Pulsating heat pipe with gradient wetting surface and preparation method thereof |
| US20200319685A1 (en) * | 2019-04-08 | 2020-10-08 | Inventec (Pudong) Technology Corporation | Heat dissipation assembly and portable electronic device |
| US20210055060A1 (en) * | 2019-08-21 | 2021-02-25 | Celsia Technologies Taiwan, Inc. | Manufacturing method and structure of heat pipe with adjustable working temperature range |
| CN113390280A (en) * | 2021-05-17 | 2021-09-14 | 昆明理工大学 | Porous special-shaped composite liquid absorption core micro heat pipe and preparation method thereof |
| CN216081103U (en) * | 2021-11-18 | 2022-03-18 | 开封富豪热能设备有限公司 | Heat pipe type heat exchanger |
-
2022
- 2022-08-16 CN CN202210982039.2A patent/CN115348805B/en active Active
Patent Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20010062646A (en) * | 1999-12-22 | 2001-07-07 | 오길록 | Heat pipe having a sintered wick structure and method for manufacturing the same |
| KR20060076831A (en) * | 2004-12-29 | 2006-07-05 | 유진컴텍(주) | Method of filling working fluid of heat pipe and appatatus thereof |
| TWI259264B (en) * | 2005-07-22 | 2006-08-01 | Forcecon Technology Co Ltd | Composite capillary structure of heat pipe |
| US20070095506A1 (en) * | 2005-10-20 | 2007-05-03 | Foxconn Technology Co., Ltd. | Heat pipe and method for making the same |
| US20070193722A1 (en) * | 2006-02-18 | 2007-08-23 | Foxconn Technology Co., Ltd. | Heat pipe with capillary wick |
| US20070204975A1 (en) * | 2006-03-03 | 2007-09-06 | Foxconn Technology Co., Ltd. | Heat pipe and method for manufacturing the same |
| US20070251673A1 (en) * | 2006-04-28 | 2007-11-01 | Foxconn Technology Co., Ltd. | Heat pipe with non-metallic type wick structure |
| US20100263833A1 (en) * | 2009-04-21 | 2010-10-21 | Yeh-Chiang Technology Corp. | Sintered heat pipe |
| DE202012008533U1 (en) * | 2012-09-03 | 2012-10-22 | Asia Vital Components Co., Ltd. | Heat pipe, cooling module and electronic connection |
| US20180313611A1 (en) * | 2015-12-28 | 2018-11-01 | Furukawa Electric Co., Ltd. | Heat pipe |
| US20200319685A1 (en) * | 2019-04-08 | 2020-10-08 | Inventec (Pudong) Technology Corporation | Heat dissipation assembly and portable electronic device |
| US20210055060A1 (en) * | 2019-08-21 | 2021-02-25 | Celsia Technologies Taiwan, Inc. | Manufacturing method and structure of heat pipe with adjustable working temperature range |
| CN110926247A (en) * | 2019-12-13 | 2020-03-27 | 大连理工大学 | Pulsating heat pipe with gradient wetting surface and preparation method thereof |
| CN113390280A (en) * | 2021-05-17 | 2021-09-14 | 昆明理工大学 | Porous special-shaped composite liquid absorption core micro heat pipe and preparation method thereof |
| CN216081103U (en) * | 2021-11-18 | 2022-03-18 | 开封富豪热能设备有限公司 | Heat pipe type heat exchanger |
Non-Patent Citations (4)
| Title |
|---|
| KAOUTAR ZEGHARI: "Experimental study of flat heat pipe for cooling TV Boxes", 2018 IEEE INTERNATIONAL TELECOMMUNICATIONS ENERGY CONFERENCE (INTELEC), 17 January 2019 (2019-01-17) * |
| 李磊;何戈宁;张富源;黄伟;霍蒙;侯晔;: "ACP1000蒸汽发生器I-690TT合金U形传热管评定技术", 核动力工程, no. 1, 30 August 2015 (2015-08-30) * |
| 谢文;刘建峰;马勇杰;李鹏;李磊磊;张玉良;: "适用于空间环境的质子交换膜燃料电池热管理技术研究", 机电产品开发与创新, no. 05, 28 September 2017 (2017-09-28) * |
| 黄宇轩;尹建成;周静波;钟毅;: ""Ω"形轴向槽道铝-丙酮热管的传热性能研究", 热加工工艺, no. 22, 25 November 2012 (2012-11-25) * |
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