CN115654980A - High-temperature heat pipe nano-structure liquid absorption core, preparation method and performance test method - Google Patents
High-temperature heat pipe nano-structure liquid absorption core, preparation method and performance test method Download PDFInfo
- Publication number
- CN115654980A CN115654980A CN202211329519.5A CN202211329519A CN115654980A CN 115654980 A CN115654980 A CN 115654980A CN 202211329519 A CN202211329519 A CN 202211329519A CN 115654980 A CN115654980 A CN 115654980A
- Authority
- CN
- China
- Prior art keywords
- absorption core
- liquid absorption
- liquid
- nano
- stainless steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000007788 liquid Substances 0.000 title claims abstract description 170
- 238000010521 absorption reaction Methods 0.000 title claims abstract description 115
- 238000000034 method Methods 0.000 title claims abstract description 59
- 239000002086 nanomaterial Substances 0.000 title claims abstract description 52
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- 238000011056 performance test Methods 0.000 title abstract description 14
- 239000011162 core material Substances 0.000 claims abstract description 120
- 238000004140 cleaning Methods 0.000 claims abstract description 14
- 238000012360 testing method Methods 0.000 claims abstract description 13
- 238000004519 manufacturing process Methods 0.000 claims abstract description 6
- 229910001220 stainless steel Inorganic materials 0.000 claims description 37
- 239000010935 stainless steel Substances 0.000 claims description 37
- 239000000835 fiber Substances 0.000 claims description 34
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 21
- 230000008569 process Effects 0.000 claims description 19
- 230000000630 rising effect Effects 0.000 claims description 18
- 239000007787 solid Substances 0.000 claims description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 239000008367 deionised water Substances 0.000 claims description 14
- 229910021641 deionized water Inorganic materials 0.000 claims description 14
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 12
- 238000005520 cutting process Methods 0.000 claims description 12
- 238000005245 sintering Methods 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 10
- 239000002184 metal Substances 0.000 claims description 10
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 9
- 238000007254 oxidation reaction Methods 0.000 claims description 9
- 238000012545 processing Methods 0.000 claims description 9
- 230000003287 optical effect Effects 0.000 claims description 8
- 230000003647 oxidation Effects 0.000 claims description 8
- 239000002245 particle Substances 0.000 claims description 8
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 8
- 239000004519 grease Substances 0.000 claims description 7
- 238000005406 washing Methods 0.000 claims description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 6
- 239000003344 environmental pollutant Substances 0.000 claims description 6
- 239000002105 nanoparticle Substances 0.000 claims description 6
- 230000033116 oxidation-reduction process Effects 0.000 claims description 6
- 231100000719 pollutant Toxicity 0.000 claims description 6
- 239000007790 solid phase Substances 0.000 claims description 6
- 239000003153 chemical reaction reagent Substances 0.000 claims description 5
- 239000012071 phase Substances 0.000 claims description 5
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 4
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 4
- 230000001590 oxidative effect Effects 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 3
- 239000002253 acid Substances 0.000 claims description 3
- 230000004075 alteration Effects 0.000 claims description 3
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 238000007664 blowing Methods 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000000748 compression moulding Methods 0.000 claims description 3
- 238000007723 die pressing method Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 claims description 3
- 238000005530 etching Methods 0.000 claims description 3
- 230000005484 gravity Effects 0.000 claims description 3
- 230000002706 hydrostatic effect Effects 0.000 claims description 3
- 238000005259 measurement Methods 0.000 claims description 3
- 229910044991 metal oxide Inorganic materials 0.000 claims description 3
- 150000004706 metal oxides Chemical class 0.000 claims description 3
- 238000006479 redox reaction Methods 0.000 claims description 3
- 238000012876 topography Methods 0.000 claims description 3
- 230000001052 transient effect Effects 0.000 claims description 3
- 230000001133 acceleration Effects 0.000 claims description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 2
- 238000011010 flushing procedure Methods 0.000 claims description 2
- 239000002994 raw material Substances 0.000 claims description 2
- 238000003756 stirring Methods 0.000 claims description 2
- 230000008859 change Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 235000019441 ethanol Nutrition 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000001931 thermography Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000009194 climbing Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Images
Abstract
The invention discloses a high-temperature heat pipe nano-structure liquid absorption core, a preparation method and a performance test method. The preparation method and the performance test method of the liquid absorption core comprise the following steps: selecting a liquid absorption core material, preparing a liquid absorption core, cleaning the liquid absorption core, preparing a nano-structure liquid absorption core, observing a microstructure, testing wettability, testing capillary performance and the like. The invention provides a nano-structure liquid absorption core, a preparation method and a performance test method aiming at a high-temperature heat pipe, which can realize the standard manufacture and the performance test of the nano-structure liquid absorption core and provide guidance for the overall performance of the high-temperature heat pipe.
Description
Technical Field
The invention relates to the technical field of phase change heat exchange equipment, in particular to a high-temperature heat pipe nanostructure liquid absorption core, a preparation method and a performance test method.
Background
The heat pipe is a passive heat transfer device utilizing phase change (evaporation and condensation) of working media, and the liquid absorption core is used as the heart of the heat pipe and plays a crucial role in the performance of the heat pipe. The high-performance liquid absorption core requires the surface to have good wettability, so that the working medium is better spread on the surface of the liquid absorption core; meanwhile, the capillary force with high enough overcomes the reflux resistance, so that the working medium circularly reflows. Due to the complex surface appearance of the nano-structure liquid absorption core, the wettability can be enhanced, the capillary performance is improved, and the nano-structure liquid absorption core is a good choice for high-performance liquid absorption cores. The high-temperature heat pipe generally adopts alkali metal as a working medium, the property of the high-temperature heat pipe is more active, the high-temperature heat pipe is easy to be polluted in the processing and manufacturing process, the performance of the heat pipe can be influenced by factors such as cleanliness of a liquid absorption core in the heat pipe, and related process flows are still lack of specifications. The invention provides a high-temperature heat pipe nanostructure liquid absorption core, a preparation method and a performance test method aiming at the high-temperature heat pipe liquid absorption core, and provides reference for manufacturing and performance test of the high-performance high-temperature heat pipe nanostructure liquid absorption core.
Currently available methods for making nanostructured wicks include, for example: chinese patent CN201911414574.2 proposes a method for treating alkali metal heat pipe wicks: and placing the liquid absorption core in the alumina nanoparticle solution for boiling, and depositing the nano particles on the surface of the liquid absorption core to obtain the nano-structure liquid absorption core. However, the nanoparticle solution prepared by the method is not uniform, and local densification is easily formed on the surface of the liquid absorption core in the boiling process, so that local hot spots are caused, and the performance of the liquid absorption core is influenced.
Currently available methods for testing the capillary properties of nanostructured wicks include, for example: chinese patent CN202210311381.X proposes a capillary suction performance test platform and a test method thereof: the device is characterized by comprising an analytical electronic balance, a computer, a support, a chuck, a transfer module, a servo motor control module, a beaker for containing working media and a liquid absorption core clamped and fixed on the chuck, wherein the moving module moves downwards to control the liquid absorption core to be immersed in the working media in the beaker, detect the flowing condition of a working medium in the liquid absorption core in real time and evaluate the capillary performance of the liquid absorption core. However, the method neglects the influence of evaporation factors while measuring the mass change of the working medium, and only qualitatively characterizes the capillary performance by the mass change, but cannot quantify.
Disclosure of Invention
Aiming at the manufacturing, cleaning, preparation and testing of the high-temperature heat pipe liquid absorption core, the invention adopts an oxidation-reduction method to generate a nanostructure, and realizes an integrated standard flow of the high-temperature heat pipe nanostructure liquid absorption core.
The invention adopts the following technical scheme:
a high-temperature heat pipe nano-structure liquid absorption core is characterized in that through an oxidation-reduction treatment method, flaky nano-particles are generated on the surface of the liquid absorption core, so that the capillary performance of the liquid absorption core is enhanced, the flow resistance of the liquid absorption core is reduced, and the thermal performance of the high-temperature heat pipe is improved.
The preparation method of the high-temperature heat pipe nano-structure liquid absorption core comprises the following steps:
step 1: selecting a liquid absorption core material as stainless steel;
and 2, step: preparing a liquid absorption core: selecting a stainless steel fiber sintered liquid absorption core; the preparation method comprises the following steps:
step 2-1: processing stainless steel fibers: the excircle surface of a 316 type stainless steel round bar is polished, and then dry cutting is carried out on a lathe, wherein the cutting speed is 50-60 r/min, the feed rate is 0.20-0.25 mm/r, the back cutting amount is-0.19-0.23 mm, and the fiber wire with the stainless steel equivalent diameter of 95-100 mu m is obtained;
step 2-2: chopping stainless steel fibers: chopping the stainless steel fiber obtained in the step 2-1 by using a chopping blade to obtain short fiber with the length of 6-8 mm;
step 2-3: and (3) compression molding of the stainless steel fiber: performing die pressing on the short fiber obtained in the step 2-2 by adopting a strip sample sintering die;
step 2-4: solid-phase sintering: sintering the strip-shaped sample sintering mould in the step 2-3 at the high temperature of 1000-1200 ℃ for 100-145 min, so that a certain porosity is ensured while the solid-phase bonding area is ensured, and the stainless steel fiber sintered liquid absorption core is obtained;
and step 3: cleaning a liquid absorption core: the stainless steel fiber sintered wick obtained in the step 2 contains oil and fat pollutants, solid particles and metal oxides, and in order to prevent the pollutants from damaging the wick, a method of ultrasonic wave and reagent cleaning is adopted to clean the wick by the following steps:
step 3-1: removing residual oil: ultrasonic cleaning is carried out on the liquid suction core for 5-10 minutes by respectively utilizing acetone and deionized water, and surface grease is preliminarily removed;
step 3-2: acid etching and rust removal: placing the liquid absorption core in 1.5-2 mol/L diluted hydrochloric acid to remove oxides on the surface of the stainless steel;
step 3-3: and (3) quick washing: sequentially washing the liquid absorption core by using acetone, absolute methanol, absolute ethanol, isopropanol and deionized water in sequence to thoroughly remove residual grease and residual rust removal liquid;
step 3-4: and (3) drying treatment: after washing, ultrasonic cleaning is carried out again for 20-30 minutes in deionized water at the temperature of 90-95 ℃, the liquid absorption core is dried by blowing argon, and pollution removal in the drying process is ensured while solid particles are fully removed;
and 4, step 4: preparing a nano-structure liquid absorption core: placing the liquid absorption core in a metal oxidation liquid, preparing for 45-60 min at the high temperature of 85-95 ℃, and obtaining the nano-structure liquid absorption core through oxidation-reduction reaction; and (4) repeating the step (3) on the obtained nanostructure liquid absorption core, and cleaning again.
Under the cutting condition of the step 2-1, a plurality of stainless steel fibers can be obtained at one time, and the processing efficiency is high.
In the step 3: the working frequency of ultrasonic cleaning is 5-28 kHz, and solid particles on the surface of the liquid absorption core and residues after reaction with the reagent can be effectively removed.
In the step 4: the metal oxidizing solution is prepared as follows: the mass ratio of the raw materials is 8-12: 18-22: 68 to 72 phosphoric acid (H) 3 PO 4 ) Hydrogen peroxide (H) 2 O 2 ) And (3) preparing with deionized water, and stirring for 30-45 min at the water temperature of 40-55 ℃ by using a magnetic stirrer to completely dissolve solute in the metal oxidation liquid so as to achieve better oxidation reduction effect.
The performance test method of the high-temperature heat pipe nano-structure liquid absorption core comprises the following steps:
step 1: microstructure observation: placing the nano-structure liquid absorption core under a field emission scanning electron microscope for observing the micro-topography to obtain a surface image of the nano-structure liquid absorption core;
step 2: and (3) wettability testing: wettability refers to the ability or tendency of a liquid to spread on a solid surface, the stronger the wettability of the solid surface, the more rapidly the liquid spreads; shooting the expansion process of deionized water liquid drops with the volume of 2-4 mu L on the surface of the nano-structure liquid absorption core by using an optical contact angle measuring instrument to obtain a contact angle;
and step 3: and (3) testing the capillary performance: the capillary performance is represented by shooting the rising speed of the absolute ethyl alcohol in the nano-structure liquid absorption core by a Gobi long-wave infrared camera, and the capillary pressure delta P provided by the nano-structure liquid absorption core is obtained in the rising process of the absolute ethyl alcohol cap Pressure loss in the process of flowing with working medium, i.e. hydrostatic pressure delta P g And a resistance pressure drop Δ P f Phase balance:
ΔP cap +ΔP g +ΔP f ＝0 (1)
wherein, Δ P cap Calculated by the Young-Laplace equation:
ΔP g calculated by the following formula:
ΔP g ＝-ρgh (3)
Δ P of rising Process f Calculated by darcy's law:
substituting formulae (2) to (4) into formula (1) can yield:
further arranging formula (5) as:
wherein M = K/R eff The capillary performance factor is defined and represents the strength of the capillary force on the surface of the solid; in the formula:
t is time, s;
R eff -effective capillary radius, m;
h-liquid rise height, m;
g-acceleration of gravity, m/s 2 ；
Rho-density of liquid, kg/m 3 ；
ε -porosity of wick,%;
μ -dynamic viscosity of the liquid, pa/s;
k-permeability of the wick, m 2 ；
σ -surface tension of the liquid, N/m;
and (3) obtaining the rate of the absolute ethyl alcohol in the rising process of the nano-structure liquid absorption core through image processing, and obtaining M under the condition that other parameters are known.
In the step 1: the resolution of the field emission scanning electron microscope is 0.5nm @15kv, the acceleration voltage is 0.02-30kV, the beam range is 3 pA-20 nA, and high-precision image observation under different multiples is realized.
In the step 2, the measurement range of the optical contact angle measuring instrument is 0-180 degrees, the precision is 0.1 degrees, the photographing speed is 50-2000 frames/s, high-speed liquid drop transient shooting is realized, and the contact angle is accurately obtained.
In the step 3, the wettability of the ethanol in the stainless steel fiber liquid absorption core is considered to be better, so that absolute ethanol is adopted as a working medium, and the liquid rising phenomenon is more obvious; the Gobi long-wave infrared camera has the sampling frequency of 100Hz and the sampling time of 0.01s, and compared with a traditional high-speed camera shooting result, the Gobi long-wave infrared camera shows the rising process of liquid in the liquid suction core through an infrared heat image with obvious chromatic aberration, the problem that the liquid level of a colorless working medium shot by the high-speed camera is blurred is solved, and the result is accurate and reliable.
Compared with the prior art, the invention has the following advantages:
according to the invention, the stainless steel is processed, and the reasonable cutting process greatly shortens the manufacturing time of the liquid absorption core, and is simple and efficient; ultrasonic wave and cleaning treatment are carried out for a plurality of times aiming at the liquid absorption core, so that the cleanliness of the liquid absorption core is ensured, the contact angle of the cleaned liquid absorption core is obviously reduced, and hydrophobicity is changed into hydrophilicity; magnetic stirring and heating treatment are carried out on the metal oxidizing solution, so that solute in the metal oxidizing solution is fully and uniformly dissolved, and the generated nano structure is uniform and compact; microstructure observation and high-speed transient contact angle monitoring are carried out on the liquid absorption core, so that the result is visualized; aiming at the rising phenomenon of the absolute ethyl alcohol in the liquid absorption core, the thermal imaging mechanism is adopted to make the liquid rising phenomenon more obvious, and the measurement precision is effectively improved.
The invention provides a high-temperature heat pipe nano-structure liquid absorption core, a preparation method and a performance test method aiming at the problems of performance optimization and flow specification and the like of the traditional high-temperature heat pipe liquid absorption core.
The prepared metal oxidation liquid is uniform in distribution and strong in oxidation performance, the surface of the liquid absorption core can be subjected to oxidation reaction fully, and the nano structure is uniform and compact in distribution, simple and convenient.
The invention adopts a thermal imaging mechanism to observe the climbing phenomenon of ethanol in a working medium, measures the change of the height along with time, has clear and visual imaging effect, quantitatively represents a capillary performance factor through formula derivation and data fitting, and reflects the quality of the capillary performance.
Drawings
FIG. 1 is a flow chart of a method for making a nanostructured wick for a high temperature heat pipe and a performance test.
Fig. 2 is a flow diagram of a cleaning process for a high temperature heat pipe nanostructured wick.
Fig. 3 (a) and 3 (b) are high temperature heat pipe nanostructured wick surfaces at 1k and 40k times, respectively, under a scanning electron microscope.
Fig. 4 (a), 4 (b), and 4 (c) are schematic diagrams illustrating generation of a liquid droplet, an instant when the liquid droplet contacts the surface of the wick, and stabilization of the liquid droplet on the surface of the wick in the step of measuring the contact angle of the nanostructure wick of the high-temperature heat pipe under the optical contact angle measuring instrument, respectively.
Fig. 5 is a graph illustrating capillary performance testing of a nanostructure wick of a high temperature heat pipe.
Detailed Description
The invention will now be further described with reference to the following examples, and the accompanying drawings:
the invention relates to a high-temperature heat pipe nano-structure liquid absorption core, which is characterized in that flaky nano-particles are generated on the surface of the liquid absorption core by an oxidation-reduction treatment method on the basis of the traditional liquid absorption core, so that the capillary performance of the liquid absorption core is enhanced, the flow resistance of the liquid absorption core is reduced, and the thermal performance of the high-temperature heat pipe is greatly improved.
As shown in fig. 1, the present invention relates to a method for preparing a nano-structured wick for a high-temperature heat pipe and a method for testing the performance of the wick.
Step 1: selecting a liquid absorption core material: the high-temperature heat pipe requires that the liquid absorbing core material has good compatibility with the working medium, does not generate physical and chemical reaction, and ensures the integrity of the heat pipe and the purity of the working medium; stainless steel has high strength, high temperature resistance, oxidation resistance, corrosion resistance and low cost, and is an ideal liquid absorption core material in severe environments such as high temperature, corrosion, radiation and the like.
Step 2: preparing a liquid absorption core: the fiber sintered wick has a three-dimensional fully-communicated pore structure, is high in permeability and large in specific surface area, and meets the requirements of low backflow resistance and low thermal resistance of the high-performance wick, so that the stainless steel fiber sintered wick is selected; the preparation method comprises the following steps:
step 2-1: processing stainless steel fibers: performing outer circle surface finishing treatment on a 316 type stainless steel round bar, and then performing dry cutting on a lathe, wherein the cutting speed is 50r/min, the feed rate is 0.21mm/r, and the back cutting amount is 0.2mm, so as to obtain a fiber wire with the stainless steel equivalent diameter of 100 mu m;
step 2-2: chopping stainless steel fibers: chopping the stainless steel fiber filaments obtained in the step 2-1 by using a chopping blade to obtain short fiber filaments with the length of 6-8 mm;
step 2-3: and (3) compression molding of stainless steel fiber: performing die pressing on the short fiber obtained in the step 2-2 by adopting a strip sample sintering die;
step 2-4: solid-phase sintering: sintering the strip-shaped sample sintering mold in the step 2-3 at the high temperature of 1200 ℃ for 100min, ensuring a certain solid-phase bonding area and a certain porosity, and obtaining the stainless steel fiber sintered wick;
and step 3: cleaning a liquid absorption core: the stainless steel fiber type liquid absorption core obtained in the step 2 contains more grease pollutants, solid particles and metal oxides, in order to prevent the liquid absorption core from being damaged by the pollutants, a method of cleaning the liquid absorption core by ultrasonic waves and a reagent is adopted, and as shown in fig. 2, the liquid absorption core is cleaned by the following steps:
step 3-1: removing residual oil: ultrasonic cleaning is carried out on the liquid suction core for 5 minutes by respectively utilizing acetone and deionized water, and surface grease is preliminarily removed;
step 3-2: acid etching and rust removal: placing the liquid absorption core in 2mol/L diluted hydrochloric acid to remove oxides on the surface of the stainless steel;
step 3-3: and (3) quick washing: sequentially flushing the liquid absorption core by using acetone, absolute methanol, absolute ethanol, isopropanol and deionized water to thoroughly remove residual grease and residual derusting liquid;
step 3-4: and (3) drying treatment: after washing, ultrasonic cleaning is carried out again for 20 minutes in deionized water at 90 ℃, the liquid absorption core is dried by blowing argon, solid particles are fully removed, and pollution removal in the drying process is also ensured;
and 4, step 4: preparing a nano-structure liquid absorption core: placing the wick in 300mL of metal oxidation liquid, preparing for 45min at the high temperature of 95 ℃, and performing oxidation-reduction reaction to obtain the nano-structure wick; repeating the step 3 on the obtained nano-structure liquid absorption core, and cleaning again;
and 5: and (3) microstructure observation: placing the nano-structure liquid absorption core under a field emission scanning electron microscope for observing the micro-topography, so as to obtain a surface image of the nano-structure liquid absorption core;
step 6: and (3) wettability testing: wettability refers to the ability or tendency of a liquid to spread on a solid surface, the more wettable a solid surface, the more rapidly the liquid spreads. This property is critical in the design of the wick. Shooting the expansion process of deionized water liquid drops with the volume of 2 mu L on the surface of the nano-structure liquid absorption core by using an optical contact angle measuring instrument to obtain a contact angle;
and 7: and (3) testing the capillary performance: the capillary performance is represented by shooting the rising speed of the absolute ethyl alcohol in the nano-structure liquid absorption core by a Gobi long-wave infrared camera, and the capillary pressure (delta P) provided by the nano-structure liquid absorption core is used in the rising process of the absolute ethyl alcohol cap ) With pressure loss during flow of working medium (hydrostatic pressure Δ P) g And a resistance pressure drop Δ P f ) Phase balance:
ΔP cap +ΔP g +ΔP f ＝0 (1)
wherein, Δ P cap Calculated by the Young-Laplace equation:
ΔP g calculated by the following formula:
ΔP g ＝-ρgh (3)
Δ P of rising Process f Calculated by darcy's law:
substituting formulae (2) to (4) into formula (1) can yield:
further formulating formula (5) as:
wherein M = K/R eff The capillary performance factor is defined and represents the strength of the capillary force on the surface of the solid; in the formula:
t is time, s;
R eff -effective capillary radius, m;
h-liquid rise height, m;
g-acceleration of gravity, m/s 2 ；
Rho-density of liquid, kg/m 3 ；
ε -porosity of wick,%;
μ -dynamic viscosity of the liquid, pa/s;
k-permeability of the wick, m 2 ；
σ -surface tension of the liquid, N/m;
the rate of the rise of absolute ethanol in the nanostructured wick (dh/dt) was obtained by image processing, and M was calculated with other parameters known.
Fig. 2 shows a flow diagram for cleaning a high temperature heat pipe nanostructured wick.
As shown in fig. 3 (a) and 3 (b), the surfaces of the wicks prepared by the redox method have uniform and dense nanostructures, which are 1k times and 40k times of the surfaces of the high-temperature heat pipe nanostructured wicks under the scanning electron microscope.
As shown in fig. 4 (a), 4 (b) and 4 (c), the steps of measuring the contact angle of the high-temperature heat pipe nanostructure wick under the optical contact angle measuring apparatus are respectively liquid drop generation, instant when the liquid drop contacts the surface of the wick, and stable when the liquid drop is on the surface of the wick; due to the high frame rate working mode of the optical contact angle measuring instrument, the wetting process of the liquid drop on the surface of the liquid absorption core can be accurately captured, and the solid-liquid contact angle when the liquid drop is stable is obtained.
As shown in fig. 5, the capillary performance test chart of the high-temperature heat pipe nanostructure liquid absorption core is compared with the traditional high-speed camera shooting result, the long-wave infrared camera shows the rising process of liquid in the liquid absorption core through an infrared heat image with obvious chromatic aberration, the problem that the liquid level of colorless working medium shot by the high-speed camera is blurred is solved, and the result is accurate and reliable.
Claims (9)
1. A high-temperature heat pipe nano-structure liquid absorption core is characterized in that: by the oxidation-reduction treatment method, flaky nano-particles are generated on the surface of the liquid absorption core, so that the capillary performance of the liquid absorption core is enhanced, the flow resistance of the liquid absorption core is reduced, and the thermal performance of the high-temperature heat pipe is improved.
2. The method of making a high temperature heat pipe nanostructured wick according to claim 1, wherein: the method comprises the following steps:
step 1: selecting a liquid absorption core material as stainless steel;
and 2, step: preparing a liquid absorption core: selecting a stainless steel fiber sintered liquid absorption core; the preparation method comprises the following steps:
step 2-1: processing stainless steel fibers: the excircle surface of a 316 type stainless steel round bar is polished, and then dry cutting is carried out on a lathe, wherein the cutting speed is 50-60 r/min, the feed rate is 0.20-0.25 mm/r, the back cutting amount is-0.19-0.23 mm, and the fiber wire with the stainless steel equivalent diameter of 95-100 mu m is obtained;
step 2-2: chopping stainless steel fibers: chopping the stainless steel fiber filaments obtained in the step 2-1 by using a chopping blade to obtain short fiber filaments with the length of 6-8 mm;
step 2-3: and (3) compression molding of stainless steel fiber: carrying out die pressing on the short fiber obtained in the step 2-2 by adopting a strip-shaped sample sintering die;
step 2-4: solid-phase sintering: sintering the strip-shaped sample sintering mould in the step 2-3 at the high temperature of 1000-1200 ℃ for 100-145 min, so that a certain porosity is ensured while the solid-phase bonding area is ensured, and the stainless steel fiber sintered liquid absorption core is obtained;
and step 3: cleaning a liquid absorption core: the stainless steel fiber sintered wick obtained in the step 2 contains oil and fat pollutants, solid particles and metal oxides, and in order to prevent the pollutants from damaging the wick, a method of ultrasonic wave and reagent cleaning is adopted to clean the wick by the following steps:
step 3-1: removing residual oil: ultrasonic cleaning is carried out on the liquid suction core for 5-10 minutes by respectively utilizing acetone and deionized water, and surface grease is preliminarily removed;
step 3-2: acid etching and rust removal: placing the liquid absorption core in 1.5-2 mol/L diluted hydrochloric acid to remove oxides on the surface of the stainless steel;
step 3-3: and (3) quick washing: sequentially flushing the liquid absorption core by using acetone, absolute methanol, absolute ethanol, isopropanol and deionized water to thoroughly remove residual grease and residual derusting liquid;
step 3-4: and (3) drying treatment: after washing, ultrasonic cleaning is carried out again for 20-30 minutes in deionized water at the temperature of 90-95 ℃, the liquid absorption core is dried by blowing argon, and pollution removal in the drying process is ensured while solid particles are fully removed;
and 4, step 4: preparing a nano-structure liquid absorption core: placing the liquid absorption core in a metal oxidation liquid, preparing for 45-60 min at the high temperature of 85-95 ℃, and obtaining the nano-structure liquid absorption core through oxidation-reduction reaction; and (4) repeating the step (3) on the obtained nanostructure liquid absorption core, and cleaning again.
3. The method of claim 2, wherein the method comprises: under the cutting condition of the step 2-1, a plurality of stainless steel fibers can be obtained at one time, and the processing efficiency is high.
4. The method of claim 2, wherein the method comprises: in the step 3: the working frequency of ultrasonic cleaning is 5-28 kHz, and solid particles on the surface of the liquid absorption core and residues after reaction with the reagent can be effectively removed.
5. The method of claim 2, wherein the method comprises: in the step 4: the metal oxidizing solution is prepared as follows: the mass ratio of the raw materials is 8-12: 18-22: 68 to 72 of phosphoric acid H 3 PO 4 Hydrogen peroxide H 2 O 2 And (3) preparing with deionized water, and stirring for 30-45 min at the water temperature of 40-55 ℃ by using a magnetic stirrer to completely dissolve solute in the metal oxidation liquid so as to achieve better oxidation reduction effect.
6. The method of claim 1 for testing the performance of a high temperature heat pipe nanostructured wick, wherein: the method comprises the following steps:
step 1: and (3) microstructure observation: placing the nano-structure liquid absorption core under a field emission scanning electron microscope for observing the micro-topography to obtain a surface image of the nano-structure liquid absorption core;
step 2: and (3) wettability testing: wettability refers to the ability or tendency of a liquid to spread on a solid surface, and the stronger the wettability of the solid surface, the more rapidly the liquid spreads; shooting the expansion process of deionized water liquid drops with the volume of 2-4 mu L on the surface of the nano-structure liquid absorption core by using an optical contact angle measuring instrument to obtain a contact angle;
and 3, step 3: and (3) testing the capillary performance: the capillary performance is characterized by shooting the rising speed of the absolute ethyl alcohol in the nano-structure liquid absorption core by a Gobi long-wave infrared camera, and in the rising process of the absolute ethyl alcohol,capillary pressure Δ P provided by nanostructured wick cap Pressure loss in the process of flowing with working medium, i.e. hydrostatic pressure delta P g And a resistance pressure drop Δ P f Phase balance:
ΔP cap +ΔP g +ΔP f ＝0 (1)
wherein, Δ P cap Calculated by the Young-Laplace equation:
ΔP g calculated by the following formula:
ΔP g ＝-ρgh (3)
Δ P of rising Process f Calculated by darcy's law:
substituting formulae (2) to (4) into formula (1) can yield:
further arranging formula (5) as:
wherein M = K/R eff The capillary performance factor is defined and represents the strength of the capillary force on the surface of the solid; in the formula:
t is time, s;
R eff -effective capillary radius, m;
h-liquid rise height, m;
g-acceleration of gravity, m/s 2 ；
Rho-of liquidsDensity, kg/m 3 ；
ε -porosity of wick,%;
μ -dynamic viscosity of the liquid, pa/s;
k-permeability of the wick, m 2 ；
σ -surface tension of the liquid, N/m;
and (3) obtaining the rate of the absolute ethyl alcohol in the rising process of the nano-structure liquid absorption core through image processing, and obtaining M under the condition that other parameters are known.
7. The method of claim 6, wherein the method comprises the steps of: in the step 1: the resolution of the field emission scanning electron microscope is 0.5nm @15kv, the acceleration voltage is 0.02-30kV, the beam range is 3 pA-20 nA, and high-precision image observation under different multiples is realized.
8. The method of claim 6, wherein the method comprises the steps of: in the step 2, the measurement range of the optical contact angle measuring instrument is 0-180 degrees, the precision is 0.1 degrees, the photographing speed is 50-2000 frames/s, high-speed liquid drop transient shooting is realized, and the contact angle is accurately obtained.
9. The method of claim 6, wherein the method comprises the steps of: in the step 3, absolute ethyl alcohol is used as a working medium, so that the liquid rising phenomenon is more obvious; the Gobi long-wave infrared camera has the sampling frequency of 100Hz and the sampling time of 0.01s, shows the rising process of liquid in the liquid suction core through an infrared chart with obvious chromatic aberration, overcomes the problem that the liquid level of a colorless working medium shot by a high-speed camera is blurred, and ensures that the result is accurate and reliable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211329519.5A CN115654980A (en) | 2022-10-27 | 2022-10-27 | High-temperature heat pipe nano-structure liquid absorption core, preparation method and performance test method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211329519.5A CN115654980A (en) | 2022-10-27 | 2022-10-27 | High-temperature heat pipe nano-structure liquid absorption core, preparation method and performance test method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115654980A true CN115654980A (en) | 2023-01-31 |
Family
ID=84993313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211329519.5A Pending CN115654980A (en) | 2022-10-27 | 2022-10-27 | High-temperature heat pipe nano-structure liquid absorption core, preparation method and performance test method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115654980A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050092467A1 (en) * | 2003-10-31 | 2005-05-05 | Hon Hai Precision Industry Co., Ltd. | Heat pipe operating fluid, heat pipe, and method for manufacturing the heat pipe |
| CN111673086A (en) * | 2020-05-27 | 2020-09-18 | 华南理工大学 | Porous fiber liquid absorption core with surface in-situ grown carbon nano tube and preparation method |
| CN112696954A (en) * | 2020-12-29 | 2021-04-23 | 瑞声科技（南京）有限公司 | Preparation method of absorption core of heat dissipation element and heat dissipation element |
| CN113237366A (en) * | 2021-04-09 | 2021-08-10 | 瑞声科技（南京）有限公司 | Preparation method of working medium heat dissipation element |
| CN114018077A (en) * | 2021-12-13 | 2022-02-08 | 中国核动力研究设计院 | Alkali metal heat pipe liquid absorption core, preparation method thereof and heat pipe |
-
2022
- 2022-10-27 CN CN202211329519.5A patent/CN115654980A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050092467A1 (en) * | 2003-10-31 | 2005-05-05 | Hon Hai Precision Industry Co., Ltd. | Heat pipe operating fluid, heat pipe, and method for manufacturing the heat pipe |
| CN111673086A (en) * | 2020-05-27 | 2020-09-18 | 华南理工大学 | Porous fiber liquid absorption core with surface in-situ grown carbon nano tube and preparation method |
| CN112696954A (en) * | 2020-12-29 | 2021-04-23 | 瑞声科技（南京）有限公司 | Preparation method of absorption core of heat dissipation element and heat dissipation element |
| CN113237366A (en) * | 2021-04-09 | 2021-08-10 | 瑞声科技（南京）有限公司 | Preparation method of working medium heat dissipation element |
| CN114018077A (en) * | 2021-12-13 | 2022-02-08 | 中国核动力研究设计院 | Alkali metal heat pipe liquid absorption core, preparation method thereof and heat pipe |
Non-Patent Citations (2)
| Title |
|---|
| 郭凯伦等: "纳米多孔超亲水不锈钢席型网毛细力特性研究", 《核动力工程》 * |
| 黄文涛等: "氧化处理对电沉积吸液芯性能的影响研究", 《表面技术》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhang et al. | Anti-corrosive hierarchical structured copper mesh film with superhydrophilicity and underwater low adhesive superoleophobicity for highly efficient oil–water separation | |
| Im et al. | Enhanced boiling of a dielectric liquid on copper nanowire surfaces | |
| JP2014144454A (en) | Microporous hollow fiber membranes formed from perfluorinated thermoplastic polymers | |
| CN103575593A (en) | In-situ uniaxial tension observation device for mesoscale metal material | |
| CN115654980A (en) | High-temperature heat pipe nano-structure liquid absorption core, preparation method and performance test method | |
| CN113848174B (en) | Electrochemical corrosion test device under boiling and strong corrosive solution environment and application thereof | |
| CN105445230A (en) | Method and apparatus for measurement of chirality of carbon nanotube | |
| CN107285647B (en) | Optical fiber surface processing device | |
| US10907258B1 (en) | Surface modification of metals and alloys to alter wetting properties | |
| CN111530295B (en) | Inclined dipping preparation method of tubular ceramic membrane inner membrane | |
| KR101619403B1 (en) | Preparation method of hollow fiber membrane and hollow fiber membrane | |
| CN103983628B (en) | A kind of preparation method of copper mesh base blade shape gold SERS active-substrate | |
| Wu et al. | Dynamic nano-imaging via a microsphere compound lens integrated microfluidic device with a 10× objective lens | |
| Tovmash et al. | Fabrication of sorption-filtering nonwoven material from ultrafine polyvinyl alcohol carbonized fibres by electrospinning | |
| Midiani et al. | Investigation the effect of powder type on the capillary pumping performance and wettability | |
| US20120120986A1 (en) | Thermocouple and thermometer using that | |
| JP2009236738A (en) | Metal specimen collection sampler and sampling method using it | |
| Xu et al. | Experimental investigation on wettability of refrigerants on laser-ablated surfaces | |
| CN111964500B (en) | Method for preparing flexible micro heat pipe by laser-induced reduction sintering of copper oxide ink | |
| CN111982812A (en) | Method for realizing optical super-resolution imaging by utilizing micron-scale liquid drops generated in real time | |
| CN109212667A (en) | The optical fiber optical tweezers probe with secondary cone angle prepared with two step method | |
| CN111965158A (en) | Single-step rapid preparation method of porous silicon-gold dendritic crystal composite structure | |
| CN106908017B (en) | Free-float space robot device and its measurement method based on metal human lymph node fluorescence | |
| CN113340698B (en) | Eroding agent for observing metallographic structure of zirconium alloy and method for preparing metallographic sample of zirconium alloy | |
| Paiman et al. | Effect of sintering temperature on the fabrication of ceramic hollow fibre membrane |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20230131 |