CN111102865B - Metal-nonmetal composite capillary core applied to loop heat pipe system and preparation method thereof - Google Patents
Metal-nonmetal composite capillary core applied to loop heat pipe system and preparation method thereof Download PDFInfo
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- CN111102865B CN111102865B CN202010015853.8A CN202010015853A CN111102865B CN 111102865 B CN111102865 B CN 111102865B CN 202010015853 A CN202010015853 A CN 202010015853A CN 111102865 B CN111102865 B CN 111102865B
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- 239000002131 composite material Substances 0.000 title claims abstract description 41
- 238000002360 preparation method Methods 0.000 title abstract description 11
- 239000000843 powder Substances 0.000 claims abstract description 158
- 239000002245 particle Substances 0.000 claims abstract description 128
- 238000001704 evaporation Methods 0.000 claims abstract description 68
- 239000002184 metal Substances 0.000 claims abstract description 63
- 229910052751 metal Inorganic materials 0.000 claims abstract description 63
- 239000011148 porous material Substances 0.000 claims abstract description 42
- 238000013329 compounding Methods 0.000 claims abstract description 3
- 239000000693 micelle Substances 0.000 claims description 19
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Classifications
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- 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
- F28D15/043—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 forming loops, e.g. capillary pumped loops
-
- 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)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Physics & Mathematics (AREA)
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- General Engineering & Computer Science (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
The invention discloses a metal-nonmetal composite capillary core applied to a loop heat pipe system and a preparation method thereof, belonging to the field of loop heat pipes. The capillary core is a double-aperture structure formed by compounding nonmetallic powder particles and metal powder particles, and comprises nonmetallic powder particles, metal powder particles, small-aperture pores and large-aperture pores; the nonmetallic powder particles form nonmetallic powder micro-clusters, the metal powder particles are filled among the nonmetallic powder micro-clusters, small-pore-size pores are formed among the nonmetallic powder particles, and large-pore-size pores are formed among the metal powder particles and the nonmetallic powder micro-clusters. Aiming at the problems of insufficient suction force or overlarge flow resistance of the traditional single-aperture capillary core, large heat conductivity of the double-aperture metal capillary core and easiness in forming an integral vapor film in an evaporation area to deteriorate heat transfer in the prior art, the invention provides a combination of metal-nonmetal particles, which is helpful for solving the problems of serious heat leakage, deterioration of migration of a phase interface to a liquid side, heat transfer and the like of the capillary core in operation.
Description
Technical Field
The invention relates to the technical field of loop heat pipes, in particular to a metal-nonmetal composite capillary core applied to a loop heat pipe system and a preparation method thereof.
Background
The loop heat pipe (LoopHeatPipe, abbreviated as LHP) is developed along with the space heat control technology, is an excellent heat transfer device, has the advantages of high heat flow density, no moving parts, strong temperature uniformity and the like, can perform long-distance and high-heat transmission, and has excellent heat transfer performance. The LHP operates on the principle shown in fig. 1: the liquid working medium absorbs heat and evaporates into steam in the capillary core, the steam flows to the condenser 1 through the steam pipeline 4 under the phase change drive, the steam entering the condenser 1 is condensed into liquid through condensation heat release, the condensed liquid working medium enters the compensation cavity in the evaporator 3 through the liquid pipeline 2 under the action of the capillary drive, and the liquid working medium is supplied to the phase change interface in the capillary core, so that the working medium circulation is completed, and the heat dissipation purpose is achieved. When the LHP works, liquid working medium evaporates in the capillary core inside the LHP to form a gas-liquid phase change interface, so that capillary suction force is provided, and required power is provided for the whole circulating system. From the foregoing, it is apparent that the LHP operates normally without external force, and that the driving force required for system circulation is provided by capillary suction.
The wick is the core component of LHP operation. The operating performance of the LHP is primarily dependent on the heat and mass transfer properties of the wick. The change in the position of the internal phase interface of the evaporator during operation, the size of the evaporation area and the formation of the overall vapor film are all important factors affecting the performance of the evaporator. The capillary core needs to provide enough capillary suction force in the working process to overcome the flow resistance generated in the working medium flowing process, so that the capillary core is filled with liquid working medium in time, enough liquid working medium is provided for the evaporation interface, and the gas-liquid evaporation interface is prevented from migrating to the liquid side, thereby enabling the whole LHP system to normally operate.
The conventional single-aperture capillary core, as shown in figure 2, has single aperture and large internal structure limitation. If the pore diameter is too large, a larger evaporation interface can be provided, and steam separation is facilitated, but enough capillary suction force cannot be provided for normal operation of the LHP, and a phenomenon of meniscus reversing occurs in the operation of the system; if the aperture is too small, although capillary suction force is increased, the flowing resistance of liquid working medium in the capillary core is too large, so that the working medium cannot fill the capillary core in time, and the liquid working medium required by evaporation is provided for an evaporation interface. It can be seen that there is a contradiction in the choice of these two pore sizes. The existing double-aperture capillary core is shown in figure 3, and solves the problems of suction force and flow resistance, but under high heat load, the whole effective heat conductivity of the capillary core is large, heat leakage is serious, and an evaporation interface is easy to form a whole vapor film to deteriorate heat transfer. Research into high performance capillary cores has not been stopped.
By searching, patent publication about LHP wick design is already known, such as chinese patent application number 2018208685621, filing date: 6 th 2018, 6 th month and 6 th day, the invention is named: a foam metal-fiber composite capillary core applied to loop heat pipes is characterized in that the capillary core forms a double-aperture structure in the same pore space, so that the capillary suction force of the capillary core is enhanced, the flow resistance of liquid working media is reduced, the flow of the liquid working media in the capillary core is enhanced, the back heat leakage is reduced to a certain extent, and the performance of an LHP is improved. Although this approach has partially modified the wick construction to optimize LHP performance, there is room for significant improvement in wick performance.
Disclosure of Invention
1. Technical problem to be solved by the invention
Aiming at the problems that the traditional single-aperture capillary core has insufficient suction force or overlarge flow resistance in the prior art, the double-aperture capillary core has serious heat leakage and the evaporation area is easy to form an integral vapor film to deteriorate heat transfer, the metal-nonmetal composite capillary core applied to a loop heat pipe system and the preparation method thereof are provided, which are beneficial to solving the problems that the capillary core has serious heat leakage in operation, and the phase interface is poor in transferring heat to the liquid side.
2. Technical proposal
In order to achieve the above purpose, the technical scheme provided by the invention is as follows:
The invention relates to a metal-nonmetal composite capillary core applied to a loop heat pipe system, which is a double-aperture structure formed by compositing nonmetal powder particles and metal powder particles, and comprises nonmetal powder particles, metal powder particles, small-aperture pores and large-aperture pores; the nonmetallic powder particles form nonmetallic powder micro-clusters, the metal powder particles are filled among the nonmetallic powder micro-clusters, small-pore-size pores are formed among the nonmetallic powder particles, and large-pore-size pores are formed among the metal powder particles and the nonmetallic powder micro-clusters.
Further, the metal powder particles have a particle diameter of 10 to 100 μm.
Further, the particle size of the nonmetallic powder particles is 1-10 μm.
Still further, the diameter of the non-metallic powder micelles is greater than the diameter of the metallic powder particles.
Still further, the ratio of the total volume of the non-metallic powder particles to the metallic powder particles is between 0.2 and 1.
The invention discloses a preparation method of a metal-nonmetal composite capillary core applied to a loop heat pipe system, which comprises the following steps:
S1, preparing nonmetal powder particles and metal powder particles by taking nonmetal and metal materials;
S2, mixing nonmetal powder particles with a solvent to prepare nonmetal powder micelle powder slurry in a flowing state; pouring non-metal powder micelle powder slurry into a forming die to prepare a non-metal micelle framework;
S3, mixing the metal powder particles with a solvent to prepare metal powder slurry in a flowing state;
S4, pouring the metal powder slurry into a forming die filled with non-metal powder micro-clusters, and mixing to enable the metal powder to fill the non-metal powder micro-clusters;
And S5, taking out the solid capillary core blank from the mold after filling, cleaning to remove the additive in the capillary core, and heating and evaporating to dryness to obtain the solid capillary core.
Further, the metal powder particles have a particle diameter of 10 to 100 μm.
Further, the particle size of the nonmetallic powder particles is 1-10 μm.
Still further, the diameter of the non-metallic powder micelles is greater than the diameter of the metallic powder particles.
Still further, the ratio of the total volume of the non-metallic powder particles to the metallic powder particles is between 0.2 and 1.
3. Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:
(1) The metal-nonmetal composite capillary core is prepared by mixing nonmetal powder particles with small particle size and metal powder particles with large particle size, and forms a capillary core with local uneven heat transfer, a dispersed two-phase evaporation area and a whole vapor film which are difficult to form, so that the critical heat flow of the capillary core is improved, the quality of the capillary core is lighter than that of the traditional capillary core, the plasticity is strong, the hardness is high, the porosity is high, the interface area of an evaporation phase is increased, and the surface evaporation rate and the critical heat flow are improved.
(2) According to the metal-nonmetal composite capillary core applied to the loop heat pipe system, in the evaporation process, nonmetal powder particles have a stretching effect on the evaporation meniscus of the composite capillary core, so that an evaporation interface is not easy to form an integral vapor film, the integral evaporation heat transfer coefficient is increased, the critical heat flow of evaporation heat transfer is improved, the integral effective heat conduction coefficient is reduced, the back heat leakage is reduced, and the operation performance of the LHP is improved.
(3) The metal-nonmetal composite capillary core applied to the loop heat pipe system forms local large-aperture pores through the metal powder particles, is favorable for expansion of an evaporation interface in the metal-nonmetal composite capillary core, increases the evaporation phase change interface area, improves the surface evaporation rate, and causes small flow resistance when liquid working medium flows in the large aperture, so that the capillary core is filled with the liquid working medium in time. The small-aperture pores formed by the nonmetallic powder particles provide enough capillary suction force for the operation of the LHP, provide enough liquid working medium for a gas-liquid evaporation interface, and simultaneously have lower heat conductivity which is unfavorable for evaporation, so that the phase change interface can be maintained on the inner wall surface of the evaporator, the liquid supply to the evaporation interface is ensured, the back-up of the evaporation meniscus of the composite capillary core is prevented, and the adverse factors to evaporation are reduced.
(4) The preparation method of the metal-nonmetal composite capillary core applied to the loop heat pipe system adopts a casting mode for preparation, is safe and environment-friendly, is simple in preparation, saves resources and reduces cost investment.
Drawings
Figure 1 is a schematic diagram of the LHP operation;
FIG. 2 is a schematic diagram of a partial operation process of a single pore capillary wick under high thermal load;
FIG. 3 is a schematic diagram of a partial operation process of a dual-aperture capillary wick under high thermal load;
FIG. 4 is a schematic diagram of the partial operation of a metal-nonmetal composite wick applied to a loop heat pipe system according to the present invention.
Reference numerals in the schematic drawings illustrate:
1. A condenser; 2. a liquid conduit; 3. an evaporator; 4. a steam pipe;
101. Heating the wall surface; 102. single aperture evaporation meniscus; 103. single pore size metal particles; 104. single pore diameter wick gas phase; 105. single pore capillary wick liquid phase; 106. a single pore diameter capillary core pore diameter;
111. a dual aperture wick meniscus; 112. dual pore size metal particles; 113. a dual pore capillary wick liquid phase; 114. a dual pore capillary vapor phase; 115. double-aperture capillary core large aperture; 116. the double-aperture capillary core has a small aperture;
121. Non-metallic powder particles; 122. evaporating the meniscus by the composite wick; 123. metal powder particles; 124. small pore size pores; 125. a composite wick vapor phase; 126. large pore size pores; 127. and (3) compounding the liquid phase of the capillary core.
Detailed Description
For a further understanding of the present invention, the present invention will be described in detail with reference to the drawings.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
The invention is further described below with reference to examples.
Example 1
As shown in fig. 2, the capillary core is prepared from single-aperture metal particles 103, a single-aperture capillary core aperture 106 is formed between adjacent single-aperture metal particles 103, under the heating wall 101, a single-aperture evaporation meniscus 102 is formed between a single-aperture capillary core gas phase 104 and a single-aperture capillary core liquid phase 105, and if the aperture is too large, the phenomenon that the single-aperture evaporation meniscus 102 backs up occurs in the system operation; if the aperture is too small, although capillary suction force is increased, the flowing resistance of liquid working medium in the capillary core is too large, so that the working medium cannot be filled in the capillary core in time, the liquid working medium required by evaporation is provided for an evaporation interface, and the normal use performance is affected.
As shown in fig. 3, the partial operation state diagram of the dual-aperture capillary core in industry under high heat load is shown, the capillary core is a dual-aperture capillary core formed by dual-aperture metal particles 112, and the metal particles form a large-and-small-aperture structure, comprising a dual-aperture capillary core large aperture 115 and a dual-aperture capillary core small aperture 116; specifically, a small pore 116 of a dual-pore capillary core is formed between two adjacent dual-pore metal particles 112, and a large pore 115 of a dual-pore capillary core is formed between a cluster-shaped framework surrounded by a plurality of dual-pore metal particles 112. Compared with a single-aperture capillary core, the capillary core solves the problems of suction force and flow resistance, but under high heat load, as shown in fig. 3, the double-aperture capillary core meniscus 111 between the double-aperture capillary core gas phase 114 and the double-aperture capillary core liquid phase 113 is easy to form an integral vapor film to deteriorate heat transfer, and normal use performance is affected.
The metal-nonmetal composite capillary core of the present embodiment can solve the above-mentioned problems, as shown in fig. 4, the metal-nonmetal composite capillary core of the present embodiment is applied to a loop heat pipe system, and the capillary core has a dual-aperture structure formed by compositing nonmetal powder particles 121 and metal powder particles 123, and includes nonmetal powder particles 121, metal powder particles 123, small-aperture pores 124 and large-aperture pores 126; the non-metal powder particles 121 form non-metal powder micelles, the metal powder particles 123 are filled between the non-metal powder micelles, small-pore-diameter pores 124 are formed between the non-metal powder particles 121, large-pore-diameter pores 126 are formed between the metal powder particles 123, and between the metal powder particles 123 and the non-metal powder micelles. In use, as shown in FIG. 4, the composite wick evaporation meniscus 122 between the composite wick gas phase 125 and the composite wick liquid phase 127 exhibits a calabash shape under high thermal load.
The particle diameter of the metal powder particles 123 in this embodiment is 10-100 μm, the particle diameter of the nonmetal powder particles 121 is 1-10 μm, and the diameter of the nonmetal powder micelles is larger than the diameter of the metal powder particles 123, and the ratio of the total volume of the nonmetal powder particles 121 and the metal powder particles 123 is between 0.2-1. The limit capillary core of the embodiment is prepared by adopting a casting mode, and the specific preparation process is as follows:
s1, preparing nonmetallic powder particles 121 and metal powder particles 123 by taking nonmetallic and metal materials;
In the embodiment, the metal material is selected, and metals with large heat conductivity coefficient, high hardness and high temperature resistance, such as Ti, cu, al and the like, are selected; the nonmetallic material is selected from nonmetallic materials with small heat conductivity, high temperature resistance and strong plasticity, such as cement, ceramic, polytetrafluoroethylene and the like, the particle size of the prepared metal powder particles 123 is 10-100 mu m, and the particle size of the nonmetallic powder particles 121 is 1-10 mu m.
S2, mixing the nonmetallic powder particles 121 with a solvent to prepare nonmetallic powder micelle powder slurry in a flowing state; pouring non-metal powder micelle powder slurry into a forming die to prepare a non-metal micelle framework;
Specifically, the particle size of the non-metal powder particles 121 is smaller, the particle size of the metal powder particles 123 is larger, firstly, the non-metal powder particles 121 with small particles are made into non-metal powder micro-clusters with large particles, according to the property of non-metal materials, an adaptive solvent such as water is selected, the non-metal powder particles 121 with small particles are mixed with an appropriate solvent, and appropriate additives such as adhesive starch or ammonium bicarbonate are added, so that slurry is conveniently formed, non-metal powder micro-cluster slurry is prepared, the non-metal powder micro-clusters can be in a flowing state, the diameter of the non-metal powder micro-clusters is 200-800 μm and is larger than the diameter of the metal powder particles 123, and the subsequent filling of the metal powder micro-cluster slurry is facilitated; pouring the prepared nonmetallic powder micelle powder slurry into a forming die with a set size to prepare a nonmetallic micelle framework;
s3, mixing the metal powder particles 123 with a solvent to prepare metal powder slurry in a flowing state;
Similarly, according to the properties of the metal powder particles 123, an adaptive solvent such as water is selected, the metal powder particles 123 are mixed with a proper solvent, and additives such as NaCl or ammonium bicarbonate are added to prepare a flowing metal powder particle slurry, and the slurry is thinner and is convenient to fill;
S4, pouring the metal powder slurry into a forming die filled with non-metal powder micro-clusters, and mixing to enable the metal powder to fill the non-metal powder micro-clusters;
in this embodiment, the ratio of the total volume of the non-metal powder particles 121 to the total volume of the metal powder particles 123 is between 0.2 and 1, the evaporation heat transfer performance of the capillary determines the LHP performance, if the non-metal occupies a larger volume than the metal, the partial evaporation of the capillary is reduced, the evaporation rate of the evaporator is reduced, and the LHP performance is reduced, so that the total volume of the metal powder particles 123 is larger than the volume of the non-metal powder particles 121; if the total volume of the metal is too large, the total effective heat conductivity of the composite capillary core is increased, the heat leakage is serious, and the heat transfer is deteriorated; in this embodiment, the ratio of the total volume of the non-metal powder particles 121 to the total volume of the metal powder particles 123 is controlled to be 0.2-1, so that the quality of the capillary core can be effectively ensured.
And S5, taking out the solid capillary core blank from the die after filling, cleaning and removing the additive in the capillary core, and performing ultrasonic cleaning, heating and evaporating to dryness to obtain the finished product.
The capillary core of this embodiment is formed by mixing nonmetallic powder particles 121 with small particle size and metallic powder particles 123 with large particle size, so as to prepare a capillary core with locally uneven heat transfer, and the evaporation interface forms a dispersed two-phase evaporation area, so that an integral vapor film is not easy to form, thereby improving the critical heat flow of the capillary core, and compared with the traditional capillary core, the capillary core has the advantages of light weight, strong plasticity, high hardness, high porosity, increased evaporation phase interface area, and improved surface evaporation rate and critical heat flow. Because of the high thermal conductivity of the metal powder particles 123 and the local large-aperture pores 126 formed between the metal powder particles 123, expansion of the evaporation interface in the interior of the metal powder particles is facilitated, the evaporation phase change interface area is increased, the surface evaporation rate is improved, and the liquid working medium in the large aperture flows to generate smaller flow resistance, so that the capillary core is filled with the liquid working medium in time. The small-bore pores 124 formed by the non-metallic powder particles 121 provide sufficient capillary suction for LHP operation, provide sufficient liquid working medium for the vapor-liquid evaporation interface, and simultaneously have low thermal conductivity which is unfavorable for evaporation, so that the phase change interface can be maintained on the inner wall surface of the evaporator, the liquid supply to the evaporation interface is ensured, the evaporation meniscus 122 of the composite capillary core is prevented from reversing, and adverse factors to evaporation are reduced. In addition, during the evaporation process, the nonmetal powder particles 121 stretch the evaporation meniscus 122 of the composite capillary wick, so that an integral vapor film is not easy to form at an evaporation interface, the evaporation heat transfer coefficient is increased, the critical heat flow of the evaporation heat transfer is improved, the integral effective heat conduction coefficient is reduced, the back heat leakage is reduced, and the operation performance of the LHP is improved.
Compared with the traditional single Kong Maoxi core and the existing double-aperture capillary core, the metal-nonmetal composite capillary core applied to the loop heat pipe system has the following advantages when the LHP works:
A. The phase change evaporation interface is increased, the heat and mass transfer effect is better, and the maximum critical heat load is improved:
The composite capillary core of the embodiment has the advantages that the evaporation interface area is increased, the surface evaporation rate is increased, and the evaporation capacity is also increased. The capillary core inner hole contact surface is rough, has a certain stretching effect on the liquid working medium, prolongs the length of the gas phase, liquid phase and solid phase three-phase contact line, optimizes the evaporation interface environment, has higher local heat conductivity, can ensure that the local temperature of the gas-liquid evaporation interface is rapidly increased, can ensure that the evaporation interface is not easy to form an integral air film, enhances the evaporation heat and mass transfer effect, and ensures that the maximum critical heat load is increased.
B. the back heat leakage is greatly reduced, and the overall temperature of LHP operation is reduced:
The compensation chamber temperature determines the LHP operating temperature. The composite capillary core of the embodiment has the advantages that the nonmetal with low heat conductivity exists and occupies a certain proportion, compared with the traditional capillary core, the integral effective heat conductivity coefficient in the capillary core is greatly reduced, the heat load of the system is mainly used for evaporation of a phase interface, so that the heat load of heat entering the compensation cavity through heat leakage of the capillary core is greatly reduced, the back heat leakage is effectively reduced, the temperature of the compensation cavity is lower, and therefore, the integral operation temperature of the LHP is reduced.
C. the liquid supply effect of the capillary core is good:
Compared with the traditional single-hole capillary core and the traditional double-hole capillary core, the composite capillary core of the embodiment has the advantages that the metal powder particles 123 surround the nonmetal powder micro-clusters made of the nonmetal powder particles 121 with small particle sizes, the small holes formed among the nonmetal powder particles 121 provide enough suction force for LHP operation, the large holes formed among the metal powder particles 123 and the nonmetal powder micro-clusters effectively reduce the flow resistance of liquid working media in the capillary core, so that liquid supply is enhanced. Meanwhile, the effective aperture in the composite capillary core of the embodiment is smaller, the capillary suction force is increased, enough liquid is provided for evaporation of a gas-liquid interface during operation, and the gas-liquid evaporation interface is prevented from migrating to the liquid side.
D. Temperature fluctuation is reduced, and starting performance of the loop heat pipe is accelerated:
The composite capillary core of this embodiment adopts the metal powder particles 123 with high thermal conductivity, and when a thermal load is applied to the upper wall surface of the capillary core, the thermal conductivity of the metal is high, so that the local temperature of the upper wall surface of the capillary core can be rapidly increased, and local effective evaporation occurs on the upper wall surface of the capillary core in a short time, thereby accelerating the starting performance of the LHP. The integral effective heat conductivity coefficient in the capillary core is reduced, the heat leakage of the evaporator is reduced, the temperature of the compensation cavity is low and the fluctuation is small, and the evaporation interface continuously generates gas to be discharged through the channel in time, so that the temperature fluctuation of the evaporator is reduced.
E. The preparation is simple:
the composite capillary core is prepared in a casting mode, is safe and environment-friendly, is simple to prepare, saves resources and reduces cost investment.
The invention and its embodiments have been described above by way of illustration and not limitation, and the invention is illustrated in the accompanying drawings and described in the drawings in which the actual structure is not limited thereto. Therefore, if one of ordinary skill in the art is informed by this disclosure, the structural mode and the embodiments similar to the technical scheme are not creatively designed without departing from the gist of the present invention.
Claims (8)
1. A metal-nonmetal composite capillary core applied to a loop heat pipe system, which is characterized in that: the capillary core is a double-aperture structure formed by compounding nonmetallic powder particles (121) and metal powder particles (123), and comprises nonmetallic powder particles (121), metal powder particles (123), small-aperture pores (124) and large-aperture pores (126); the nonmetallic powder particles (121) form nonmetallic powder micro-clusters, the metal powder particles (123) are filled among the nonmetallic powder micro-clusters, small-pore-diameter pores (124) are formed among the nonmetallic powder particles (121), and large-pore-diameter pores (126) are formed among the metal powder particles (123) and the nonmetallic powder micro-clusters; the particle diameter of the metal powder particles (123) is 10-100 mu m; the particle diameter of the nonmetallic powder particles (121) is 1-10 mu m.
2. A metal-nonmetal composite wick for a loop heat pipe system according to claim 1, wherein: the diameter of the non-metallic powder micelles is larger than the diameter of the metallic powder particles (123).
3. A metal-nonmetal composite wick for a loop heat pipe system according to any one of claims 1-2, wherein: the ratio of the total volume of non-metallic powder particles (121) to metallic powder particles (123) is between 0.2 and 1.
4. The method for preparing the metal-nonmetal composite capillary core applied to the loop heat pipe system as claimed in claim 1, wherein the method comprises the following steps: the method comprises the following steps:
S1, preparing nonmetal powder particles (121) and metal powder particles (123) by taking nonmetal and metal materials;
S2, mixing nonmetal powder particles (121) with a solvent to prepare nonmetal powder micelle powder slurry in a flowing state; pouring non-metal powder micelle powder slurry into a forming die to prepare a non-metal micelle framework;
S3, mixing the metal powder particles (123) with a solvent to prepare metal powder slurry in a flowing state;
S4, pouring the metal powder slurry into a forming die filled with non-metal powder micro-clusters, and mixing to enable the metal powder to fill the non-metal powder micro-clusters;
And S5, taking out the solid capillary core blank from the mold after filling, cleaning to remove the additive in the capillary core, and heating and evaporating to dryness to obtain the solid capillary core.
5. The method for preparing the metal-nonmetal composite capillary core applied to the loop heat pipe system as claimed in claim 4, wherein the method comprises the following steps: the metal powder particles (123) have a particle diameter of 10-100 μm.
6. The method for preparing the metal-nonmetal composite capillary core applied to the loop heat pipe system as claimed in claim 4, wherein the method comprises the following steps: the particle diameter of the nonmetallic powder particles (121) is 1-10 mu m.
7. The method for preparing the metal-nonmetal composite capillary core applied to the loop heat pipe system as claimed in claim 4, wherein the method comprises the following steps: the diameter of the non-metallic powder micelles is larger than the diameter of the metallic powder particles (123).
8. The method for preparing the metal-nonmetal composite capillary core applied to the loop heat pipe system according to any one of claims 4 to 7, which is characterized in that: the ratio of the total volume of non-metallic powder particles (121) to metallic powder particles (123) is between 0.2 and 1.
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