Evaporator component and loop heat pipe

Abstract

The invention provides an evaporator component which comprises an evaporator, a first liquid storage device, a second liquid storage device and a capillary wick, the first liquid storage device and the second liquid storage device are arranged at the left end and the right end of the evaporator, and the evaporator is filled with the capillary wick. The capillary core extends into the first liquid storage device and the second liquid storage device from the middle of the evaporator to the left side and the right side, liquid inlets are formed in the left side of the first liquid storage device and the right side of the second liquid storage device respectively, and the two steam outlets are formed in the upper end of the evaporator. The evaporator is provided with the two loops, the two loops operate at the same time in a double-inlet and double-outlet mode, and compared with an evaporator with a double liquid storage device and a single inlet and a single outlet, the two loops of the evaporator are completely the same in the path length for supplementing working media, so that the supplementing of the working media is more stable.

Description

Technical Field

[0001] The invention relates to a novel double-liquid storage evaporator, belonging to the technical field of loop heat pipes and the heat pipe field of F28d15 / 02. Background Art

[0002] Heat pipe technology is a heat transfer element called "heat pipe" invented by George Grover of Los Alamos National Laboratory in the United States in 1963. It makes full use of the principle of heat conduction and the rapid heat transfer properties of phase change media. It transfers the heat of the heating object to the outside of the heat source quickly through the heat pipe. Its thermal conductivity exceeds that of any known metal.

[0003] Heat pipe technology was previously widely used in aerospace, military and other industries. Since it was introduced into the radiator manufacturing industry, people have changed the design ideas of traditional radiators, getting rid of the single cooling mode that simply relies on high air volume motors to obtain better cooling effects. The use of heat pipe technology enables radiators to obtain satisfactory heat exchange effects, opening up a new world for the cooling industry. At present, heat pipes are widely used in various heat exchange equipment, including nuclear power and computer fields, such as the utilization of waste heat from nuclear power.

[0004] A loop heat pipe refers to a closed loop heat pipe. It is generally composed of an evaporator, a condenser, a liquid reservoir, and steam and liquid pipelines. Its working principle is: a heat load is applied to the evaporator, the working fluid evaporates on the outer surface of the evaporator capillary core, the generated steam flows out of the steam channel into the steam pipeline, and then enters the condenser to condense into liquid and supercool. The reflux liquid enters the liquid trunk through the liquid pipeline to replenish the evaporator capillary core, and the cycle continues in this way. The circulation of the working fluid is driven by the capillary pressure generated by the evaporator capillary core, and no external power is required. Since the condensing section and the evaporating section are separated, loop heat pipes are widely used in the comprehensive application of energy and the recovery of waste heat.

[0005] Conventional dual-reservoir loop heat pipes are developed on the basis of single-reservoir loop heat pipes. A reservoir is set at each end of the evaporator, which effectively solves the problem of insufficient liquid supply to the capillary wick in the evaporator. However, the relative distances between the two reservoirs of conventional dual-reservoir loop heat pipes for liquid supply are different, resulting in unbalanced liquid supply at both ends of the capillary wick, insufficient anti-gravity, anti-impact and anti-bumping capabilities, and is not conducive to improving the stability of the loop heat pipe under different postures.

[0006] The present invention designs a novel dual-liquid reservoir evaporator component, improves the structure of a traditional loop heat pipe, adopts a symmetrical dual-circuit design and a dual-liquid reservoir liquid supply design, and proposes a new structure evaporator component, which makes up for the defect of insufficient liquid supply of a traditional single liquid reservoir, and effectively improves the cooling effect of the reflux liquid on the dual-liquid reservoir structure under different postures in a gravity field or a bumpy environment, ensuring that the evaporator component can achieve uniform temperature and stable liquid supply to the capillary core in the evaporator in any posture under a gravity field or a bumpy environment, thereby improving the ability to resist gravity, impact and bumps, and improving the stability of the device. Summary of the invention

[0007] The present invention aims to adapt to different orientations in a gravity field or an acceleration field, greatly improve the application range of the heat pipe thermal control system, and at least solve one of the technical problems existing in the prior art or related technology. The present invention proposes a dual-liquid reservoir evaporator component with good integration effect, strong stability, anti-gravity, anti-bumping, anti-impact, high pressure resistance, and deformation resistance.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] An evaporator component comprises an evaporator, a first liquid reservoir, a second liquid reservoir and a capillary wick, wherein the first liquid reservoir and the second liquid reservoir are arranged at the left and right ends of the evaporator, the evaporator is filled with a capillary wick, and the capillary wick extends from the middle of the evaporator to the left and right sides to the inside of the first liquid reservoir and the second liquid reservoir, liquid inlets are respectively arranged on the left side of the first liquid reservoir and the right side of the second liquid reservoir, and two steam outlets are arranged at the upper end of the evaporator.

[0010] As an improvement, the positions where the two steam outlets are connected to the capillary wick are symmetrical along the middle position of the capillary wick.

[0011] As an improvement, the steam outlet is connected to a steam pipeline, and the steam pipeline is inserted into the capillary core in the evaporator from the upper end, and the position of insertion into the capillary core is symmetrical along the middle position of the capillary core.

[0012] As an improvement, the liquid inlet is connected to the liquid pipeline.

[0013] As an improvement, two liquid pipelines are respectively inserted into the first liquid reservoir and the second liquid reservoir, and holes are set in the center of both ends of the capillary core, and the first liquid phase pipeline and the second liquid phase pipeline are inserted into the holes of the capillary core.

[0014] As an improvement, unconnected holes are symmetrically opened at both ends of the capillary core in the evaporator towards the inside of the capillary core, a metal wire mesh sub-capillary core is arranged inside the hole, and the periphery of the capillary core has multiple rectangular steam grooves of the same length as the capillary core, and two annular steam grooves are symmetrically opened along the middle of the evaporator.

[0015] As an improvement, the liquid storage device is composed of a liquid storage part and an end cover, and the end cover is coaxially arranged with the liquid storage part and connected by welding.

[0016] As an improvement, the bottom of the liquid reservoir has a 1mm rounded corner.

[0017] As an improvement, the side wall of the liquid reservoir is provided with a through hole.

[0018] A loop heat pipe comprises the evaporator component mentioned above.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1) The loop heat pipe is provided with dual circuits, and the two circuits are operated simultaneously in the form of dual inlet and dual outlet. Compared with the loop heat pipe with dual liquid reservoirs and single inlet and single outlet, the two circuits of the loop heat pipe are exactly the same in the path length of the working fluid replenishment, making the replenishment of the working fluid more stable.

[0021] 2) This loop heat pipe has dual liquid reservoirs symmetrically arranged on both sides of the evaporator. Under special working conditions such as tilting and acceleration, the contact area between the working fluid in the liquid reservoir on one side and the capillary wick is reduced, and the contact area between the working fluid in the liquid reservoir on the other side and the capillary wick is inevitably increased, thereby achieving stable replenishment of the working fluid under special working conditions and avoiding the drying up of the capillary wick. It can make up for the poor working stability of the traditional single liquid reservoir, and has the ability to resist gravity, bumps and impacts, and can adapt to different orientations in the gravity field or acceleration field, greatly improving the application range of the heat pipe thermal control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a double liquid reservoir heat pipe structure of the present invention;

[0023] Figure 2 It is a front cross-sectional view of a double-liquid reservoir heat pipe of the present invention;

[0024] Figure 3 This is a schematic diagram of the connection structure between the gas phase pipeline and the saddle

[0025] Figure 4 It is a schematic diagram of the double reservoir and saddle structure;

[0026] Figure 5 is a schematic diagram of a symmetrical capillary wick structure;

[0027] Figure 6 It is a schematic diagram of the connection between the liquid reservoir and the filling pipe;

[0028] Figure 7 It is a scanning electron microscope of a super-hydrophilic nickel-based capillary core with a capillary structure surface functionalized in the present invention;

[0029] Figure 8It is a pure nickel capillary core scanning electron microscope without PMMA addition;

[0030] Fig. 9 This is a comparison chart of suction performance in the capillary structure capillary suction;

[0031] Fig.10 This is the display diagram of FTIR functional group analysis results;

[0032] Fig.11 It is the capillary wick process preparation process.

[0033] Figure 1 In the figure, 1-1 is an evaporator, 1-2 is a first liquid reservoir, 1-3 is a second liquid reservoir, 1-4 is a first filling port, 1-5 is a second filling port, 1-6 is a first vapor phase pipeline, 1-7 is a second vapor phase pipeline, 1-8 is a first condenser, 1-9 is a second condenser, 1-10 is a first liquid phase pipeline, and 1-11 is a second liquid phase pipeline;

[0034] Figure 2-3 In the figure, 2-1 is a capillary core, 1-2-1 is a first liquid reservoir end cap, 1-3-1 is a second liquid reservoir end cap, 1-2-2 is a first liquid reservoir liquid storage component, 1-3-2 is a second liquid reservoir liquid storage component, 1-1-1 is a saddle, 1-1-2 is a hollow cylinder 1, 1-1-3 is a hollow cylinder 2, 1-2-3 is a hollow cylinder 3, and the right symmetrical part 1-3-3 is a hollow cylinder 4;

[0035] Figure 5 In the figure, 5-1 is a capillary wick rectangular steam channel, and 5-2 is a capillary wick annular steam channel. DETAILED DESCRIPTION

[0036] The specific implementation modes of the present invention are described in detail below with reference to the accompanying drawings.

[0037] In this article, unless otherwise specified, “ / ” represents division, and “×” and “*” represent multiplication.

[0038] In the description of the present invention, terms such as "inside", "outside", "up", "down", "front", "back", "left", and "right" indicating directions or positional relationships are based on the positions or orientational relationships shown in the accompanying drawings, and do not indicate or imply a specific installation and operating direction that the described device or element must have, and therefore cannot be understood as a limitation on the present invention.

[0039] It should be noted that in the description of the present invention, the terms "set", "installation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a connection between the two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances. In addition, the terms "one", "two", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0040] The technical solutions in the embodiments of the present invention will be supplemented below with reference to the accompanying drawings in the embodiments of the present invention.

[0041] Figure 1 A dual-liquid reservoir heat pipe is disclosed. Figure 1 The double liquid reservoir loop heat pipe shown includes an evaporator 1-1, a first condenser 1-8, a second condenser 1-9, a first liquid reservoir 1-2, a second liquid reservoir 1-3, a first vapor phase pipeline 1-10, a second vapor phase pipeline 1-7, a first liquid phase pipeline 1-6 and a second liquid phase pipeline 1-11; the evaporator 1-1, the first vapor phase pipeline 1-6, the first condenser 1-8, the first liquid phase pipeline 1-10 and the first liquid reservoir 1-2 are connected in sequence to form a first loop, and the evaporator 1-1, the second vapor phase pipeline 1-7, the first liquid phase pipeline 1-6 and the second liquid phase pipeline 1-11 are connected in sequence to form a first loop. The pipeline 1-7, the second condenser 1-9, the second liquid phase pipeline 1-11 and the second liquid reservoir 1-3 are connected in sequence to form a second loop; the first liquid reservoir 1-2 and the second liquid reservoir 1-3 are arranged at the left and right ends of the evaporator 1; the capillary core 2-1 is filled inside the evaporator, and the first vapor phase pipeline 1-6 and the second vapor phase pipeline 1-7 are inserted into the evaporator 1 from the upper end, and the positions where the first vapor phase pipeline 1-6 and the second vapor phase pipeline 1-7 are inserted into the evaporator 1 are symmetrical along the middle position of the evaporator 1.

[0042] This loop heat pipe has dual liquid reservoirs symmetrically arranged on both sides of the evaporator. Under special working conditions such as tilting, acceleration, etc., the contact area between the working fluid in the liquid reservoir on one side and the capillary wick is reduced, while the contact area between the working fluid in the liquid reservoir on the other side and the capillary wick is inevitably increased, thereby achieving stable replenishment of the working fluid under special working conditions and avoiding the drying up of the capillary wick. It can make up for the poor working stability of the traditional single liquid reservoir and has the ability to resist gravity, bumps and impacts, and can adapt to different orientations in the gravity field or acceleration field, greatly improving the scope of application of the heat pipe thermal control system.

[0043] This loop heat pipe is equipped with dual circuits, and adopts a dual-inlet and dual-outlet form to enable the two circuits to operate simultaneously. Compared with the loop heat pipe with dual liquid reservoirs and single inlet and single outlet, the two circuits of this loop heat pipe are exactly the same in the path length of replenishing the working fluid, making the replenishment of the working fluid more stable.

[0044] As an improvement, the capillary wick 2-1 extends from the middle position of the evaporator 1 to the left and right sides to the inside of the first liquid reservoir 1-2 and the second liquid reservoir 1-3. The capillary wick and the evaporator are interference fit, and transitions are provided at both ends of the capillary wick. The capillary wick extends excessively into the inside of the liquid reservoir 1-2 and 1-3. The capillary wick extends excessively into the inside of the liquid reservoir so that it can fully contact the liquid phase working medium, which is conducive to the capillary wick sucking the liquid phase working medium from the inside of the liquid reservoir, ensuring that the liquid can be stably sucked under various working conditions.

[0045] As an improvement, the first liquid phase pipeline 1-10 and the second liquid phase pipeline 1-11 are respectively inserted into the first liquid reservoir 1-2 and the second liquid reservoir 1-3, and as Figure 6 As shown, holes are set in the center of both ends of the capillary core, and the first liquid phase pipeline and the second liquid phase pipeline are inserted into the holes of the capillary core. The liquid phase working medium can be directly replenished into the capillary core through the liquid phase pipeline, shortening the liquid replenishment time and increasing the working medium circulation speed.

[0046] As an improvement, the first liquid phase pipeline and the second liquid phase pipeline extend into the hole of the capillary wick in the evaporator. Preferably, the distance extended into the evaporator is 30-40% of the length of the evaporator, which can effectively reduce the flow resistance of the liquid phase working medium and quickly reach the inside of the capillary wick.

[0047] As an improvement, Figure 5 As shown, non-connected holes are symmetrically opened at both ends of the capillary core in the evaporator toward the inside of the capillary core, a metal wire mesh sub-capillary core is arranged inside the hole, a plurality of rectangular steam channels 5-1 of the same length as the capillary core are arranged on the periphery of the capillary core, and two annular steam channels 5-2 are symmetrically opened along the middle of the evaporator.

[0048] The capillary core described in the loop heat pipe has openings on both sides and is not connected in the middle, so that the two side loops are separated to a certain extent; but due to the penetration effect of the porous structure of the capillary core, when the pressure in one side of the loop is too high, the working fluid can also flow from the side loop with high pressure to the other side loop through the porous structure, which plays a role in buffering the pressure, so that the dual loops of the loop heat pipe have stable operation.

[0049] The capillary core of the loop heat pipe is provided with a rectangular steam channel on the periphery, which increases the total volume of the channel, facilitates the timely overflow of the gaseous working medium, and improves the heat exchange capacity; at the same time, as a passage between the two side loops, it can balance the air pressure under the working condition where the air pressure difference on both sides is large, thereby improving the stability of the operation of the loop heat pipe;

[0050] Two annular steam channels are symmetrically distributed in the middle of the capillary core of the loop heat pipe, which plays a role in storing steam and balancing the air pressure of each rectangular steam channel, thereby further improving the stability of the operation of the loop heat pipe.

[0051] A plurality of rectangular steam channels pass through the two annular channels of the capillary core described in the loop heat pipe, balancing the pressure on the left and right sides of the capillary core to achieve stable input and output of steam.

[0052] As an improvement, the ends of the first vapor phase pipeline 1-6 and the second vapor phase pipeline 1-7 are respectively located above the left and right annular steam channels of the capillary wick. The gas phase working medium can flow into the steam pipeline quickly, effectively reducing the flow resistance of the gas phase working medium.

[0053] As an improvement, the evaporator and the first and second liquid reservoirs are designed and processed in an integrated manner. The evaporator and liquid reservoir described in the loop heat pipe are designed and processed in an integrated manner, which simplifies the processing technology and improves the ability to resist pressure and deformation.

[0054] As an improvement, the liquid storage devices are composed of liquid storage components 1-2-2, 1-3-2 and end covers 1-2-1, 1-3-1, and the end covers 1-2-1, 1-3-1 are connected to the liquid storage components 1-2-2, 1-3-2 by welding.

[0055] As an improvement, the vapor phase pipeline and the liquid phase pipeline are manufactured in an integrated manner, and the liquid phase pipeline passes through the hollow cylindrical hole opened on the end cover and then extends into the central hole of the capillary core through the liquid reservoir, preferably at a depth of 70 mm.

[0056] As an improvement, a hollow cylinder with a length of 5 mm and a wall thickness of 1 mm is symmetrically arranged on the upper part of the evaporator saddle, and the distance between the center points of the two hollow cylinders is 13 mm. The first vapor phase pipeline and the second vapor phase pipeline 2 extend into the saddle 5 mm through the hollow cylinders respectively.

[0057] The evaporator 1-1, the liquid storage 1-2 and the liquid storage 1-3 are an integrated structure. Figure 2 , 3As shown, the evaporator 1-1 includes an external saddle 2-6 and an internal capillary core 2-1. The external saddle 1-1-1 and the internal capillary core 2-1 are interference fit; the two ends of the capillary core 2-1 are respectively 15mm deep into the liquid reservoir 1-2 and the liquid reservoir 1-3. Above the saddle 2-6, there are symmetrically provided protruding hollow cylinders 2-7 and 2-8 with a length of 5mm, a wall thickness of 1mm, and a 45° chamfer at the edge of the port, and the distance between the center points of the two hollow cylinders is 13mm. The vapor phase pipeline 1-6 and the vapor phase pipeline 1-7 extend into the saddle 1-1-1 by 5mm through the hollow cylinder 1-1-2 and the hollow cylinder 1-1-3 respectively. The liquid reservoir 1-2 includes a liquid storage portion 1-2-2 and an end cap 1-2-1. A hollow cylindrical protrusion 1-2-3 with a length of 5 mm and a thickness of 1 mm is provided at the center of the end cap 1-2-1. The edges of both ends of the hollow cylinder 1-2-3 have a 2 mm 45° chamfer. The liquid reservoir 1-3 includes a liquid storage portion 1-3-2 and an end cap 1-3-1. A hollow cylindrical protrusion 1-3-3 with a length of 5 mm and a thickness of 1 mm is provided at the center of the end cap 1-3-1. The edges of both ends of the hollow cylinder 1-3-3 have a 2 mm 45° chamfer. Figure 5 As shown, the two ends of the capillary core 2-1 are symmetrically provided with unconnected holes, the periphery of the capillary core has a plurality of rectangular steam channels 5-1 of the same length as the capillary core, and the middle part has symmetrically provided with an annular steam channel 5-2 and an annular steam channel 5-3. Figure 6 As shown, the filling pipe 1-4 and the filling pipe 1-5 are respectively located in the liquid reservoir 1-2 and the liquid reservoir 1-3, and extend into the liquid reservoir 1-2 and the liquid reservoir 1-3.

[0058] As a preference, Figure 2 As shown, the evaporator consists of an external saddle and an internal capillary wick.

[0059] As a preference, Figure 2 As shown, the outer saddle is provided with a circular through hole.

[0060] As a preference, Figure 2 As shown, the capillary core is interference fit with the circular through hole provided in the saddle, the capillary core protrudes 17 mm on both sides of the circular through hole provided in the saddle, and the capillary core and the saddle are arranged symmetrically.

[0061] The circular through hole of the saddle of the present invention is coaxially arranged with the liquid storage parts 1-2-2 and 1-3-2, and the evaporator and the liquid storage parts 1-2-2 and 1-3-2 are manufactured as one body, which can simplify the processing flow, improve production efficiency, and improve the ability to resist pressure and deformation.

[0062] As a preference, Figure 2 As shown, the liquid reservoir 1-2 (1-3) is composed of a liquid storage part 1-2-2 (1-3-2) and an end cover 1-2-1 (1-3-1).

[0063] As a preference, Figure 3 As shown, the bottom of the liquid reservoirs 1-2 and 1-3 has a 1mm rounded corner.

[0064] As a preference, Figure 2 As shown, the side walls of the liquid reservoirs 1-2 and 1-3 are provided with through holes.

[0065] As a preference, Figure 2 As shown, the outer sides of the liquid storage parts 1-2-2 and 1-3-2 are provided with end covers 1-2-1 and 1-3-1, and the end covers 2-2 and 2-3 are coaxially arranged with the liquid storage parts 1-2-2 and 1-3-2 and connected by welding.

[0066] As a preference, Figure 6 As shown, the filling pipe 1-4 and the filling pipe 1-5 are respectively inserted into the liquid reservoir 1-2 and the liquid reservoir 1-3, and play the role of filling the working fluid before the operation of the loop heat pipe. After the working fluid is filled, the filling ports of the filling pipe 1-4 and the filling pipe 1-5 are sealed by welding.

[0067] Preferably, the capillary core 2-1 adopts a sintering process using a volatile and salt-soluble pore-forming agent to achieve the attachment of organic functional groups and achieve a super-hydrophilic effect. The specific surface area of ​​the new capillary core reaches 1.04 m^2 / g, which is 2.5 times higher than that of the capillary core sintered using graphite-like carbon nitride as a pore-forming agent, and has excellent suction performance.

[0068] Porous materials have developed pore structures and are now widely used in aerospace, transportation, environmental protection, and petrochemical industries. As an important application, the capillary wick in the loop heat pipe (LHP) evaporator utilizes the capillary suction and permeability of porous materials. The performance of the capillary wick is the key to the overall performance of the loop heat pipe. The capillary wick with good suction effect and heat pipe operation effect requires not only a certain porosity and hydrophilicity, but also certain requirements for the microscopic distribution of the pore size and mechanical strength of the capillary wick. In the traditional capillary wick sintering process, the pore size and pore distribution of the capillary wick are usually changed by adjusting the molding pressure and sintering temperature and other parameters, and the porosity is changed to adjust the suction performance. There are also methods to adjust the pore size of the capillary wick and change the porosity of the capillary wick by adding pore-forming agents. At present, most of the studies use soluble salt or volatile pore-forming agents to adjust the geometric structure of the pores and control the micropore diameter to optimize the capillary force of the capillary wick, such as sodium chloride, carbon nitride, and ammonium bicarbonate. However, adding such pore-forming agents only changes the size and shape of the pores at the microscopic level of the capillary wick, and optimizes capillary suction by regulating surface tension. This method has the problem of being unable to accurately control the micropores during the sintering process and being unable to regulate the micropores across scales, resulting in a low upper limit for the optimization of capillary suction. In addition, the pores generated by this method are generally large in diameter and unevenly distributed, making the pore-forming process difficult to control, and it is impossible to obtain a capillary wick with a uniform pore size distribution. Selecting a pore-forming agent that can simultaneously control the physical properties of the capillary wick micropores and the hydrophilic and hydrophobic chemical properties of the surface, and optimizing the sintering process, can simultaneously make the capillary wick have the potential for high capillary wick suction performance and super hydrophilic properties, which is expected to become a method to further improve the suction performance of sintered capillary wicks.

[0069] The material of the capillary wick 2-1 includes metal nickel chain spherical powder, calcium chloride powder, and PMMA powder, wherein the mass fractions of the components are as follows: 8 parts of metal nickel chain spherical powder, 0.5-1.5 parts of calcium chloride powder, and 0.5-1.5 parts of PMMA powder.

[0070] Metallic nickel has good chemical stability and is not easily oxidized in the air; PMMA, as a carbon-based high molecular polymer, decomposes violently under heat, producing volatile gases that violently impact metallic nickel powder, which can produce a large number of meteorite-like pores, making it a good volatile pore-forming agent. At the same time, the decomposition process produces a large number of carbon-containing hydrophilic functional groups, and nickel and carbon can easily form stable carbon-nickel bonds at high temperatures; calcium chloride powder has a much higher melting point than metallic nickel, is easily soluble in water and has low corrosiveness, making it a good lava pore-forming agent; in summary, these three ingredients were selected.

[0071] Compared with the capillary cores in the prior art, it is possible to attach hydrophilic functional groups to the surface of the metal capillary core, form a large number of nano-scale pores on the surface of the micron-scale metal powder, and achieve super-hydrophilic properties. At the same time, compared with the existing capillary cores sintered with volatile and soluble salt pore-forming agents in the same proportion, the mechanical strength is effectively improved.

[0072] Reducing the proportion of calcium chloride or PMMA will greatly reduce the suction performance of the capillary wick and lose its super hydrophilicity; increasing the proportion of calcium chloride or PMMA will make it impossible to form the capillary wick during sintering, and the mechanical strength of the capillary wick will be greatly reduced, making it impossible to demold and process. Therefore, the above mass fractions are also reasonable choices made after a large number of experiments, which not only ensure the processing technology, but also the performance.

[0073] As an improvement, the size of the metal nickel chain spherical powder is 1μm-10μm, the particle size of the calcium chloride powder is 10μm-100μm, and the particle size of the PMMA powder is 500 mesh-3000 mesh. If the size of the metal nickel powder is not within this range, the suction performance of the capillary wick will be significantly reduced; if the calcium chloride powder is smaller than this range, the suction performance of the capillary wick will be significantly reduced, and if it is larger than this range, the suction performance and mechanical strength will be significantly reduced; if the PMMA powder is smaller than this range, the number of nano-scale pores will be significantly reduced, and if it is larger than this range, the capillary wick cannot be formed.

[0074] As an improvement, the size of the metal nickel chain spherical powder is 4 μm-6 μm, the particle size of the calcium chloride powder is 40 μm-60 μm, and the particle size of the PMMA powder is 1200 mesh-1800 mesh.

[0075] The preparation method of the surface functionalized super-hydrophilic nickel-based capillary wick is as follows:

[0076] S1, putting the raw materials into a vacuum drying oven and drying them thoroughly;

[0077] S2, putting the above raw materials into a powder mixer according to the proportion and mixing them thoroughly;

[0078] S3, putting the mixed raw materials after being fully mixed into a mold, and vibrating them on a vibration table;

[0079] S4, using a pressing head and a mold to perform artificial pre-pressing, and measuring the amount of the raw material filled;

[0080] S5, repeating the steps of S3 and S4 until the raw material in the mold basically meets the pre-installed value;

[0081] S6, placing the mold into a sintering furnace for cold pressing to form the desired embryonic body;

[0082] S7, vacuum sintering the formed embryo body;

[0083] S8, demoulding the green body after sintering, and machining the inner hole, outer circle and groove;

[0084] In the step S1, the drying vacuum is ≤0.01Pa, the drying temperature is 70-90℃, and the time is 4h-6h; if the vacuum does not meet the requirements, the raw materials will undergo oxidation reaction, changing the hydrophilicity of the material and the hydrophilicity of the capillary wick after sintering; if the drying temperature is lowered, the raw material powder will clump and affect the mixing uniformity, and the temperature increase will cause the thermal decomposition reaction of PMMA; if the time is too short, it cannot be effectively dried, and clumps will be produced, affecting the mixing uniformity. Therefore, after a large number of experiments, the above-mentioned appropriate vacuum degree and drying time and temperature are selected.

[0085] The raw materials in step S2 are 8 parts of metal nickel chain spherical powder, 0.5-1.5 parts of calcium chloride powder, and 0.5-1.5 parts of PMMA powder;

[0086] In the step S6, the molding pressure is 5-25MPa, and the holding time is 3000s-6000s; the above pressure and time are reasonable choices made after a large number of experiments. If the molding pressure is lower than this range, sintering cannot be formed; if it is higher than this range, the inside of the capillary core will be densified, reducing or losing the suction performance; if the holding time is too short, sintering cannot be formed; if the holding time is too long, the inside of the capillary core will be densified, reducing or losing the suction performance.

[0087] In the S7 step, the vacuum sintering pressure is ≤0.01Pa, the first step sintering temperature is 500-600K, the heating rate is 5-15K / min, and the holding time is 0-30min, the second step sintering temperature is 650-750K, the heating rate is 5-10K / min, and the holding time is 0-10min, and the third step sintering temperature is 950-1000K, the heating rate is 5-15K / min, and the holding time is 60-90min.

[0088] As an improvement, the sintering temperature of the first step is 600K, the heating rate is 10K / min, and the holding time is 0-30min. The sintering temperature of the second step is 700K, the heating rate is 5-10K / min, and the holding time is 0-10min. The sintering temperature of the third step is 973K, the heating rate is 10K / min, and the holding time is 60min.

[0089] If the sintering temperature in the first step is lower than this range, PMMA cannot decompose and cannot form hydrophilic functional groups. If it is higher than this range, the decomposition is too intense, which affects the formation of the capillary core. If the heating rate is too fast, PMMA will decompose too intensely, which affects the formation of the capillary core. If the sintering temperature in the second step is too high or the heating rate is too fast, it will affect the reaction between the carbon-containing functional groups and the nickel metal, which will reduce or lose the attachment of the hydrophilic functional groups on the surface. If the sintering temperature in the third step is too high or the holding time is too short, the capillary core will not be able to form, and the suction performance will be reduced or lost. Therefore, the above reasonable selection of sintering steps and time can further improve the efficiency and function of the processing.

[0090] The beneficial effects of the present invention are as follows: by optimizing the sintering process of the metal nickel capillary wick, innovatively selecting the salt-soluble pore-forming agent calcium chloride and the volatile pore-forming agent PMMA, a layer of 5-10nm hydrophilic functional groups is formed on the surface of the capillary wick, and at the same time, nanoscale holes with an average pore size of 2nm-200nm and an average pore size of 11nm are formed on the surface of the metal nickel particles. Compared with the traditional metal nickel capillary wick, the present invention has super-hydrophilic properties and significantly improves the water pumping effect of the capillary wick. Compared with the traditional salt-soluble and volatile pore-forming agent capillary wick, the present invention significantly improves the stiffness of the capillary wick and significantly enhances the machining performance. Further improve the operating stability of the loop heat pipe and improve the heat transfer capacity of the loop heat pipe.

[0091] See also Fig.10 , combined with the XRD and XPS analysis results, it is proved that the volatile pore-forming agent PMMA and the soluble salt pore-forming agent CaCl2 have no residual phase, and many hydrophilic oxygen-containing functional groups are left after the decomposition of PMMA.

[0092] See also Figure 7 , 8 ,SEM scanning electron microscopy and BET test results show that a large number of nano-scale pores are generated during the sintering process, which more than doubles the specific surface area.

[0093] See also Fig. 9 The present invention has very good suction performance and very fast suction speed, which is 200-400 seconds faster than the capillary core with the same size and the same pore-forming agent ratio.

[0094] As an improvement, Fig. 9 As shown, the mass percentage of calcium chloride powder is 5-15%, and the mass percentage of PMMA powder is 5-15%. Further preferably, the mass percentage of calcium chloride powder is 15%, and the mass percentage of PMMA powder is 5%. At this time, the suction performance reaches the best.

[0095] Example 1: Use a uniform particle size of 1 μm diameter chain ball-shaped nickel powder, a particle size of 10 μm calcium chloride powder, and a particle size of 500 mesh PMMA powder. The three raw materials were placed in a vacuum drying oven with a vacuum degree of 0.01Pa, a temperature of 90°C, and dried for 4 hours. After drying, take out the raw materials and mix them evenly according to the mass ratio of Ni:CaCl2:PMMA of 8:0.5:1.5. After mixing, put it into the sintering mold, and measure it manually for many times until it meets expectations. Cold pressing molding, the molding pressure is 25MPa. The vacuum degree of the vacuum sintering furnace is 0.001Pa, the first step is sintering at 600K, the heating rate is 15K / min, and the insulation time is 0min; the second step is sintering at 750K, the heating rate is 10K / min, and the insulation time is 0min; the third step is sintering at 1000K, the heating rate is 15K / min, and the insulation time is 60min. After cooling, demoulding, washing in clean water, washing off the soluble salt pore-forming agent, and finally drying. Its final porosity is 72%

[0096] Example 2: Use a uniform particle size of 2μm diameter chain ball-shaped metal nickel powder, a particle size of 20μm calcium chloride powder, and a particle size of 1500 mesh PMMA powder. The three raw materials were placed in a vacuum drying oven with a vacuum degree of 0.01Pa, a temperature of 90°C, and dried for 4h. After drying, take out the raw materials and mix them evenly according to the mass ratio of Ni:CaCl2:PMMA of 8:1:1. After mixing, put it into the sintering mold, and measure it manually for multiple pre-compression until it meets expectations. Cold pressing molding, the molding pressure is 10MPa. The vacuum degree of the vacuum sintering furnace is 0.001Pa, the first step is sintering at 600K, the heating rate is 10K / min, and the insulation time is 20min; the second step is sintering at 700K, the heating rate is 5K / min, and the insulation time is 10min; the third step is sintering at 970K, the heating rate is 10K / min, and the insulation time is 70min. After cooling, demoulding, washing in clean water, washing off the soluble salt pore-forming agent, and finally drying.

[0097] Its final porosity is 70%. As shown in the figure, there are a large number of nano-scale meteorite-like pores distributed on the surface of the capillary wick.

[0098] As a preference, Figure 5 As shown, non-connected holes are symmetrically opened at both ends of the capillary core 2-1 toward the inside of the capillary core, with a hole diameter of 8 mm and a hole depth of 80 mm; the periphery of the capillary core 2-1 has a plurality of rectangular steam channels 5-1 of the same length as the capillary core, and at the same time, two annular steam channels 5-2 and 5-3 of 6 mm in length are symmetrically opened at a distance of 7 mm from the middle of the capillary core, the annular steam channels 5-2 and 5-3 divide the rectangular steam channel 5-1 into three parts, and the rectangular steam channels on both sides are symmetrical about the center of the capillary core 2-1.

[0099] The present invention designs and processes the rectangular steam channel 5-1 to increase the total volume of the channel, which is easy for the gaseous working medium to overflow in time and improve the heat exchange capacity; at the same time, as a passage between the two side loops, it can balance the air pressure under the working condition where the air pressure difference on both sides is large, thereby improving the stability of the operation of the loop heat pipe; the design and processing of the symmetrically arranged annular steam channels 5-2 and 5-3 play the role of storing steam and balancing the air pressure of each rectangular steam channel, thereby further improving the stability of the operation of the loop heat pipe.

[0100] Preferably, the loop heat pipe is provided with symmetrical dual liquid reservoirs 1-2 and 1-3. Under special working conditions such as tilting, acceleration, etc., the contact area between the working fluid in the liquid reservoir on one side and the capillary wick 2-1 is reduced, and the contact area between the working fluid in the liquid reservoir on the other side and the capillary wick 2-1 is inevitably increased, thereby achieving stable replenishment of the working fluid under special working conditions and avoiding the drying up of the capillary wick 2-1. This can make up for the poor working stability of the traditional single liquid reservoir, and has the ability to resist gravity, bumps, and impacts, and can adapt to different orientations in the gravity field or acceleration field, greatly improving the scope of application of the heat pipe thermal control system.

[0101] Preferably, the gas phase pipelines 1-6, 1-7 and the liquid phase pipelines 1-10, 1-11 are all manufactured in an integrated manner and have the same radius.

[0102] As a preference, Figure 4 As shown, the gas pipeline 1-6 and the gas pipeline 1-7 are respectively extended into the cylindrical holes symmetrically opened above the saddle, and the lower ends of the gas pipeline 1-6 and the gas pipeline 1-7 are tangent to the inner wall of the through hole opened in the saddle, and the gas pipeline 1-6 and the gas pipeline 1-7 are connected and sealed with the cylindrical holes symmetrically opened above the saddle by welding.

[0103] Preferably, the condenser must be selected according to actual working conditions and can be clamped on the gas-liquid intersection pipeline to achieve efficient condensation of the gas phase working medium.

[0104] Preferably, the liquid phase pipeline 1-10 and the liquid phase pipeline 1-11 extend 85 mm into the liquid reservoir 1-2 and 1-3 through the cylindrical holes 1-2-3 and 1-3-3 opened in the center of the end covers 1-2-1 and 1-3-1, and the liquid phase pipelines 1-10 and 1-11 are connected and sealed with the cylindrical holes opened in the center of the end covers 1-2-1 and 1-3-1 by welding.

[0105] As a preference, Figure 2 As shown, the liquid phase pipeline 1-10 and the liquid phase pipeline 1-11 extend 70 mm into the holes opened at the center of the two sides of the capillary core 2-1, so that the capillary core 2-1 can fully absorb the working fluid to ensure the stable operation of the loops on both sides of the loop heat pipe.

[0106] The present invention adopts a dual-circuit design and a dual-inlet and dual-outlet form to enable two circuits to operate simultaneously. Compared with a loop heat pipe with a dual liquid reservoir and a single-inlet and single-outlet, the two circuits of the loop heat pipe are completely the same in the path length of the working fluid replenishment, making the replenishment of the working fluid more stable.

[0107] The gas-liquid two-phase circuit and liquid storage structure described in the present invention realize the separation of gas-liquid two-phase working fluids and improve the heat exchange efficiency; after the evaporator is heated, the liquid phase working fluid is converted into gas phase working fluid, which is transported to the condenser through the vapor phase pipeline and condensed into liquid phase working fluid, thereby realizing the long-distance transmission of heat.

[0108] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. An evaporator component, comprising an evaporator, a first liquid reservoir, a second liquid reservoir and a capillary wick, wherein the first liquid reservoir and the second liquid reservoir are arranged at the left and right ends of the evaporator, the evaporator is filled with a capillary wick, and the capillary wick extends from the middle of the evaporator to the left and right sides to the inside of the first liquid reservoir and the second liquid reservoir, a liquid inlet is arranged on the left side of the first liquid reservoir and the right side of the second liquid reservoir, and two steam outlets are arranged at the upper end of the evaporator.

2. The evaporator component according to claim 1, characterized in that The positions where the two steam outlets are connected to the capillary wick are symmetrical along the middle position of the capillary wick.

3. The evaporator component according to claim 2, characterized in that The steam outlet is connected to a steam pipeline, and the steam pipeline is inserted into the capillary core in the evaporator from the upper end, and the position of inserting into the capillary core is symmetrical along the middle position of the capillary core.

4. The evaporator component according to claim 1, characterized in that The liquid inlet is connected to the liquid pipeline.

5. The evaporator component according to claim 4, characterized in that The two liquid pipelines are respectively inserted into the first liquid reservoir and the second liquid reservoir, and holes are arranged at the centers of both ends of the capillary core, and the first liquid phase pipeline and the second liquid phase pipeline are inserted into the holes of the capillary core.

6. The evaporator component according to claim 4, characterized in that Unconnected holes are symmetrically opened at both ends of the capillary core in the evaporator, and a metal wire mesh sub-capillary core is arranged inside the hole. The periphery of the capillary core has multiple rectangular steam channels of the same length as the capillary core, and two annular steam channels are symmetrically opened along the middle of the evaporator.

7. The evaporator component according to claim 1, wherein: The liquid reservoirs are composed of a liquid storage component and an end cover, and the end cover is coaxially arranged with the liquid storage component and connected by welding.

8. The evaporator component according to claim 1, wherein: The bottom of the reservoir has a 1 mm rounded corner.

9. The evaporator component according to claim 1, characterized in that The side wall of the liquid storage container is provided with a through hole.

10. A loop heat pipe, characterized in that: An evaporator component comprising any one of claims 1-9.

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