阅读说明：本技术 一种航天环路热管辐射器复合热控系统 (Composite thermal control system of aerospace loop heat pipe radiator ) 是由 郭春生 宋文哲 杨沛东 宁文婧 许艳锋 李蒸 李言伟 江程 马军 薛于凡 谷潇潇 于 2020-11-05 设计创作，主要内容包括：本发明提供了一种航天环路热管辐射器复合热控系统,所述系统包括平板式环路热管蒸发端、陶瓷加热片、辐射板、太阳能电池板、蓄电池、线路、蒸发环路管线、电磁阀和温度传感器,陶瓷加热片贴附于散热元器件上方；平板式环路热管的蒸发端紧贴于陶瓷加热片之上,冷凝端采用冷凝管线经过延伸嵌入辐射板中的结构向外散热,散热后的冷凝液循环回到蒸发端；电磁阀安装于蒸发环路管线上；蓄电池一端与环路热管蒸发端通过线路连通,一端通过线路与太阳能电池板连接；温度传感器安装于散热元器件的外侧。本发明创新性地将热管辐射器散热系统与太阳能电加热系统复合,可一体化实现零能耗的散热与保温效果。(The invention provides a composite thermal control system of a space loop heat pipe radiator, which comprises a flat plate type loop heat pipe evaporation end, a ceramic heating sheet, a radiation plate, a solar cell panel, a storage battery, a circuit, an evaporation loop pipeline, an electromagnetic valve and a temperature sensor, wherein the ceramic heating sheet is attached above a heat dissipation component; the evaporation end of the flat-plate loop heat pipe is tightly attached to the ceramic heating sheet, the condensation end adopts a structure that a condensation pipeline is extended and embedded into the radiation plate to radiate heat outwards, and condensed fluid after radiation circulates back to the evaporation end; the electromagnetic valve is arranged on the evaporation loop pipeline; one end of the storage battery is communicated with the evaporation end of the loop heat pipe through a circuit, and the other end of the storage battery is connected with the solar cell panel through a circuit; the temperature sensor is arranged on the outer side of the heat dissipation component. The invention innovatively combines the heat pipe radiator heat dissipation system with the solar electric heating system, and can integrally realize the heat dissipation and heat preservation effects with zero energy consumption.)

1. A composite thermal control system of a space loop heat pipe radiator comprises a flat plate type loop heat pipe evaporation end, a ceramic heating sheet, a radiation plate, a solar cell panel, a storage battery, a circuit, an evaporation loop pipeline, an electromagnetic valve and a temperature sensor, wherein the ceramic heating sheet is attached above a heat dissipation component; the evaporation end of the flat-plate loop heat pipe is tightly attached to the ceramic heating sheet, the condensation end adopts a structure that a condensation pipeline is extended and embedded into the radiation plate to radiate heat outwards, and condensed fluid after radiation circulates back to the evaporation end; the electromagnetic valve is arranged on the evaporation loop pipeline; the solar cell panel is attached to the outer side of the radiation plate, a heat insulation layer is arranged between the solar cell panel and the radiation plate, one end of the storage battery is communicated with the evaporation end of the loop heat pipe through a circuit, and the other end of the storage battery is connected with the solar cell panel through a circuit; the temperature sensor is arranged on the outer side of the heat dissipation component.

2. The thermal control system according to claim 1, wherein when the temperature of the heat dissipation device detected by the temperature sensor exceeds a rated temperature range, the solenoid valve is automatically opened, the loop heat pipe is started to dissipate heat of the heat dissipation device, the evaporation end of the loop heat pipe absorbs heat from the surface of the device, the liquid working medium inside the loop heat pipe is heated and evaporated on the outer surface of the capillary core, the generated vapor working medium flows into the evaporation loop pipeline through the vapor channel and then enters the radiator to dissipate the heat into the outer space through heat radiation, and the liquid after vapor condensation is circulated back to the evaporation end; when the temperature of the component detected by the temperature sensor is lower than the rated temperature range, the temperature sensor transmits the temperature parameters of the component to the controller, the controller controls the electromagnetic valve to be closed, the storage battery to output electric energy and supply power to the ceramic heating sheet, and therefore the temperature of the component is increased.

3. The thermal control system of claim 1, wherein the radiant panel is positioned outside of the satellite star and is hinged at one end and rotatable about the end; one end of the electric push rod is positioned on the surface of the satellite, and the other end of the electric push rod is positioned on the inner side of the radiation plate; the solar panel is attached to the outer side of the radiation plate.

4. The thermal control system of claim 1, wherein the system detects the position of the sun, and the radiation plate rotates under the action of the push rod to reduce the included angle between the radiation plate and the rays of the sun, thereby ensuring efficient heat dissipation of the radiation plate to the outside and reducing the temperature of the components.

5. The thermal control system of claim 1, wherein when the temperature of the heat dissipation element is within the rated operating range and the temperature of the component is higher than the evaporation end of the heat pipe, the control formula of the angle between the normal line of the radiation plate and the sunlight is as follows:

wherein:

e_n: current component temperature-current heat pipe evaporation end temperature

e_n-1: temperature of previous component-temperature of evaporation end of previous heat pipe

K_P: constant of proportionality, preferably 0.04

K_I: integration constant, preferably 0.005

K_D: the differential constant is preferably 0.5.

Technical Field

The invention belongs to the field of solar energy and loop heat pipes, and particularly relates to a composite thermal control device of a spaceflight loop heat pipe radiator.

Background

With the rapid development of modern socioeconomic, the demand of human beings on energy is increasing. However, the continuous decrease and shortage of traditional energy reserves such as coal, oil, natural gas and the like causes the continuous increase of price, and the environmental pollution problem caused by the conventional fossil fuel is more serious, which greatly limits the development of society and the improvement of the life quality of human beings. Energy problems have become one of the most prominent problems in the modern world. Therefore, the search for new energy sources, especially clean energy sources without pollution, has become a hot spot of research.

Solar energy is inexhaustible clean energy and has huge resource amount, and the total amount of solar radiation energy collected on the surface of the earth every year is 1 multiplied by 10¹⁸kW.h, which is ten thousand times of the total energy consumed in the world year. However, the solar radiation has a small energy density (about one kilowatt per square meter) and is discontinuous, which brings certain difficulties for large-scale exploitation and utilization. Therefore, in order to widely use solar energy, not only the technical problems should be solved, but also it is necessary to be economically competitive with conventional energy sources.

The heat pipe technology is a heat transfer element called a heat pipe invented by George Grover (George Grover) of national laboratory of Los Alamos (Los Alamos) in 1963, fully utilizes the heat conduction principle and the rapid heat transfer property of a phase change medium, quickly transfers the heat of a heating object to the outside of a heat source through the heat pipe, and the heat conduction capability of the heat transfer element exceeds the heat conduction capability of any known metal.

The heat pipe technology is widely applied to the industries of aerospace, military industry and the like, and since the heat pipe technology is introduced into the radiator manufacturing industry, the design idea of the traditional radiator is changed for people, the single heat radiation mode that a high-air-volume motor is used for obtaining a better heat radiation effect is avoided, the heat pipe technology is adopted for enabling the radiator to obtain a satisfactory heat exchange effect, and a new place in the heat radiation industry is opened up. At present, the heat pipe is widely applied to various heat exchange devices, including the field of space heat dissipation.

Since the twenty-first century, the enormous economic value brought by the space field and the military strategic value greatly promote the rapid development of the aerospace industry worldwide, and the thermal control system of the satellite is the key for ensuring the components to operate in the normal temperature range.

In recent years, the number of the launched small and medium-sized civil and commercial space satellites is increased year by year, and the requirement of a heat dissipation system matched with the satellites is increasingly urgent. In the design of the satellite, thermal analysis work is well done, and a proper thermal control scheme is adopted, so that the satellite has the function of playing a role in weight. As the working core and the heat dissipation main body of the satellite, the electronic equipment on the aerospace craft has the following characteristics: 1. small volume, light weight and low power consumption; 2. the device can work under severe environmental conditions; 3. high efficiency, high reliability and long service life. For small and medium-sized civil and commercial space satellites, the compact and miniaturized design concept of the space satellite makes a plurality of electronic elements integrated in a smaller and smaller area, so that the heat flux density is increased sharply, and the heat dissipation and heat preservation of electronic devices are more difficult due to the special environmental conditions; meanwhile, the development of civil and commercial satellites in China is in the starting stage, the technical level of thermal control of the satellites is relatively low, the problems of high cost, long development period and the like generally exist, and therefore the thermal control problem of the civil and commercial small and medium size satellites is urgently needed to be solved.

In conclusion, the continuously-propelled national policy system and the increasingly urgent development requirements of small and medium-sized commercial and civil satellites promote the vigorous development of the satellite thermal control industry, and provide good environmental support for our projects. The mainstream satellite heat control scheme at home and abroad and the advantages and disadvantages thereof are shown in the following table.

TABLE 1 domestic and overseas mainstream satellite thermal control scheme

The group develops a set of heat control system combining a heat pipe radiator heat dissipation system and a solar electric heating system based on the traditional LHP technology and by combining an MEMS shutter, a solar electric heating technology and a foam functional material heat dissipation technology. The system can realize zero-energy-consumption heat dissipation and heat preservation effects of high efficiency, high antigravity and high heat transfer distance in an integrated manner, so that the satellite assembly is always kept within a rated temperature range, and the service life and the working efficiency of the satellite assembly are obviously improved. Simultaneously, in order to realize the radiating effect better, this team optimizes the inner structure of heat pipe and radiant panel, add vice capillary wick structure and set up the drainage groove in order to promote its suction reflux ability in the heat pipe is inside, pack graphite alkene foamy copper material in the partial cavity of radiant panel and increase the area of contact of heat pipe loop pipeline and radiator, single heat pipe has finally realized the heat transfer power up to about 400W, can satisfy most civilian and commercial space satellite's heat dissipation demand.

According to the statistical data of the American Satellite Industry Association (SIA), commercial communication satellites account for 22 percent of the total number of global transmitting satellites by 2018 and are second only to remote sensing satellites. In addition, as shown in white paper (2019) developed by the satellite navigation and location service industry in China, the overall yield of the satellite industry in China in 2018 reaches 3016 million yuan, which is increased by 18.3% in 2017, and the demand for satellite heat dissipation is increasing.

The emission amount and the daily increase of the medium and small satellites greatly increase, the civil and commercial satellites occupy 69 percent of the medium and small satellites, but the related heat dissipation technology is still very deficient, most of the existing heat dissipation schemes are high in cost and short in service life, and the traditional heat dissipation mode of the large satellite is changed to adapt to the requirements of the medium and small aerospace satellites. The heat dissipation power of the design system meets the heat dissipation requirements of most small and medium-sized satellites, the service life can reach 15 years, the cost is only about 20 ten thousand yuan, and the cost of most heat dissipation schemes on the market is not lower than 180 ten thousand, so that the design system has a full advantage and a wide commercial market prospect in the field of small and medium-sized satellite heat dissipation.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a composite thermal control system of a novel-structure aerospace loop heat pipe radiator. The system is mainly formed by compounding a heat pipe radiator heat dissipation system and a solar electric heating system. The heat dissipation system is formed by connecting a nickel-based capillary core heat pipe and a light aluminum honeycomb composite radiation plate in series through a loop pipeline; the electric heating system is formed by connecting a ceramic heating sheet and a PET solar cell panel. In addition, the present apparatus applies stm32f103 to realize control of the entire link. The close cooperation of the heat dissipation system and the heat preservation system ensures the normal operation of the heat dissipation component.

In order to achieve the purpose, the invention adopts the following technical scheme:

a composite thermal control system of a space loop heat pipe radiator comprises a flat plate type loop heat pipe evaporation end 1, a ceramic heating sheet, a radiation plate, a solar cell panel, a storage battery, a circuit, an evaporation loop pipeline, an electromagnetic valve and a temperature sensor, wherein the ceramic heating sheet is attached above a heat dissipation component; the evaporation end of the flat-plate loop heat pipe is tightly attached to the ceramic heating sheet, the condensation end adopts a structure that a condensation pipeline is extended and embedded into the radiation plate to radiate heat outwards, and condensed fluid after radiation circulates back to the evaporation end; the electromagnetic valve is arranged on the evaporation loop pipeline; one end of the storage battery is communicated with the evaporation end of the loop heat pipe through a circuit, and the other end of the storage battery is connected with the solar cell panel through a circuit; the temperature sensor is arranged on the outer side of the heat dissipation component.

Preferably, when the temperature of the heat dissipation component detected by the temperature sensor exceeds a rated temperature range, the electromagnetic valve is automatically opened, the loop heat pipe is started to dissipate heat of the heat dissipation component, the evaporation end of the loop heat pipe absorbs heat from the surface of the component, the liquid working medium in the loop heat pipe is heated and evaporated on the outer surface of the capillary core, the generated vapor working medium flows into an evaporation loop pipeline through the vapor channel and then enters the radiator, the heat is dissipated into outer space through heat radiation, and the liquid after vapor condensation is circulated back to the evaporation end; when the temperature of the component detected by the temperature sensor is lower than the rated temperature range, the temperature sensor transmits the temperature parameters of the component to the controller, the controller controls the electromagnetic valve to be closed, the storage battery to output electric energy and supply power to the ceramic heating sheet, and therefore the temperature of the component is increased.

Preferably, the radiation plate is positioned on the outer side of the satellite star body, and one end of the radiation plate is fixed by a hinge and can rotate around the end; one end of the electric push rod is positioned on the surface of the satellite, and the other end of the electric push rod is positioned on the inner side of the radiation plate; the solar panel is attached to the outer side of the radiation plate.

Preferably, the system detects the position of the sun, and the radiation plate rotates under the action of the push rod so as to reduce the included angle between the radiation plate and the sunlight, and the radiation plate is guaranteed to radiate heat to the outside efficiently, so that the temperature of the component is reduced.

Preferably, when the temperature of the radiating element is in a rated working interval and the temperature of the element is higher than that of the evaporation end of the heat pipe, the control formula of the angle between the normal of the radiation plate and sunlight is as follows:

the angle control formula determines the angle of rotation required by the radiation plate when the radiation plate rotates from the current position to the theoretical optimal inclination angle position of the radiation plate, wherein:

e_n: current component temperature-current heat pipe evaporation end temperature

e_n-1: temperature of previous component-temperature of evaporation end of previous heat pipe

K_P: constant of proportionality, preferably 0.04

K_I: integration constant, preferably 0.005

K_D: the differential constant is preferably 0.5.

The invention has the following advantages:

1) the heat pipe radiator heat dissipation system and the solar electric heating system are innovatively combined, and the heat dissipation and heat preservation effects with zero energy consumption can be integrally realized.

2) And (5) optimizing the structure of the heat pipe. The auxiliary capillary wick is added into the liquid storage chamber of the heat pipe and inserted into the capillary wick, so that the axial capillary force of the loop is enhanced, large air bubbles of a liquid pipeline in the capillary wick can be effectively reduced, reverse heat leakage is reduced, stable forward operation of the heat pipe is ensured, and the capillary suction speed of the heat pipe is increased to 0.6 g/s.

3) The capillary suction function and the liquid backflow function of the traditional heat pipe capillary wick are separated. The heat transfer distance is obviously improved, and the farthest distance can reach 10 m. The antigravity capability is also obviously enhanced, and the antigravity height can reach 5m at most. The outstanding performance solves the problem of limitation of the using direction and length of the traditional heat pipe, and has extremely high applicability in space.

4) The structure of the radiation plate is optimized. The device adopts the design of the sandwich cellular board radiator, the structure of the cellular board has the remarkable advantage of light weight, the energy consumption caused by the lifting and running of the satellite can be effectively reduced, and the shock resistance is stronger. Graphene foam copper is filled in a cavity through which a loop pipeline passes in the cellular board, so that the contact area between the loop heat pipe and the radiator can be increased by 346.4%.

5) And the heat dissipation and heat preservation system has zero energy consumption. The heat dissipation system is spontaneously completed by means of the suction and reflux functions of the heat pipe without any energy input; the heat preservation system absorbs solar energy and converts the solar energy into electric energy to be stored by means of the solar cell panel on the outer side of the radiation plate, and when the satellite assembly needs to preserve heat, the heat preservation effect is achieved by supplying power to the heating sheet. The whole system gets rid of the dependence on external energy, and compared with other heat dissipation devices, the unit thermal control system can save 86400KJ of energy at most every day and night.

6) The heat pipe has high heat transfer efficiency. The device adopts a nickel-based capillary core ammonia working medium loop heat pipe, wherein the porosity of the nickel-based capillary core is up to more than 60%, the capillary suction speed is up to 0.6g/s, the heat resistance of the heat pipe can be stabilized at 0.15 +/-0.02 ℃/W under the charging quantity of 60%, the heat resistance is lower than the current common range of 0.18-0.32 ℃/W in the market, the overall heat transfer power can be up to 400W, the ultimate power is improved by 100W compared with that of a common heat pipe, and the overall heat transfer performance is greatly improved.

7) An optimal relation control formula of an included angle between the radiation plate and sunlight is innovatively provided, overheating or overcooling of the radiating element is avoided, and the optimal working temperature of the radiating element is guaranteed.

Description of the drawings:

FIG. 1 is a plan view of a mechanical portion of a composite thermal control system of a spacecraft loop heat pipe radiator;

FIG. 2 is a pictorial view of a flat loop heat pipe of the present invention.

FIG. 3 is a basic structure and operation diagram of the loop heat pipe of the present invention.

Fig. 4 is a physical diagram of the capillary wick of the present invention.

FIG. 5 is a view showing the internal structure of the evaporation end of the present invention.

Fig. 6 is a sectional view of a radiation plate according to the present invention.

Fig. 7 is a schematic diagram of the structure of the radiation plate of the present invention.

Fig. 8 is a schematic diagram of a heat retention system.

Fig. 9 is a simulation of the incubation system.

Fig. 10-1 is a temperature control system diagram.

Fig. 10-2 is a schematic diagram of components of the solar tracking system.

FIG. 11 is a flowchart of the apparatus operation

Fig. 12 is a schematic diagram of a process for making a wick.

FIG. 13 is a capillary wick suction experiment graph

In the drawings:

FIG. 1: 1-heat pipe and heating plate; 2-radiation plate and solar panel; 3-a storage battery; 4-line; 5-a loop line; 6-electromagnetic valve.

FIG. 5: 7-a perfusion interface; 8-accessory capillary cores; 9-hole; 10-capillary core; 11-a heat pipe housing; 12-a gas buffer chamber; 13-liquid storage chamber.

FIG. 6: 14-upper honeycomb plate; 15-lower honeycomb panel; 20-a solar panel; 21-aluminum silicate fiber paper; 23-a condensation line; 24-radiating plate edge encapsulation.

FIG. 7: 14-upper honeycomb plate; 15-gas phase working medium; 16-lower honeycomb panel; 17-graphene copper foam; 18-a loop heat pipe; 19 liquid phase working medium. Note:representing heat transfer.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

In this document, "/" denotes division and "×", "denotes multiplication, referring to formulas, if not specifically stated.

A composite thermal control device of a space loop heat pipe radiator, as shown in figure 1. The system comprises a flat-plate loop heat pipe evaporation end 1, a ceramic heating sheet (tightly attached to the flat-plate loop heat pipe evaporation end), a radiation plate (a flat-plate loop heat pipe condensation end) 2, a solar panel (tightly attached to the outer surface of the radiation plate), a storage battery 3, a circuit 4, an evaporation loop pipeline 5 and an electromagnetic valve 6. Wherein, the ceramic heating piece is attached above the heat dissipation part; the evaporation end 1 of the flat-plate loop heat pipe is tightly attached to the ceramic heating sheet, the condensation end adopts a structure that a condensation pipeline is extended and embedded into the radiation plate 2 to radiate heat outwards, and condensed fluid after radiation circulates back to the evaporation end; the electromagnetic valve 6 is arranged on the evaporation loop pipeline and ensures that the medium flowing direction is consistent with the direction of an outsider arrow of the electromagnetic valve; the accumulator 3 is connected at one end to a heat-dissipating element, preferably a ceramic heating plate, by a line and at the other end to the solar panel 20 by a line 4. Preferably, the solar cell panel is attached to the outer side of the radiation plate, and a heat insulating layer is provided between the solar cell panel and the radiation plate. And the solar panel is used for storing electricity for the storage battery.

The radiation plate 2 is positioned on the outer side of the satellite body, and one end of the radiation plate is fixed by a hinge and can rotate around the end; one end of the electric push rod is positioned on the surface of the satellite, and the other end of the electric push rod is positioned on the inner side of the radiation plate; the solar panel is attached to the outer side of the radiation plate. The used control components are as follows: the temperature sensor, the light searching module, and the controller (e.g., stm32f103) are respectively mounted on the outside of the heat radiating member, the surface of the radiation plate, and the inside of the satellite.

Preferably, the heat dissipation member is an electronic component.

TABLE 2 Components in the device and their role

The overall operation process of each component in the system is described as follows: when the temperature of the heat dissipation part detected by the temperature sensor exceeds a rated temperature range, the electromagnetic valve 6 is automatically opened, and the heat dissipation device is started to dissipate heat for the heat dissipation part. At the moment, the evaporation end of the loop heat pipe absorbs heat from the surface of the heat dissipation part, the liquid working medium in the loop heat pipe is heated and evaporated on the outer surface of the capillary core, the generated vapor working medium flows into the evaporation loop pipeline 5 through the vapor channel and then enters the radiator, the heat is dissipated into the outer space through heat radiation, and the liquid after vapor condensation is circulated back to the evaporation end. When the temperature of the heat dissipation part detected by the temperature sensor is lower than the rated temperature range, the temperature sensor transmits the temperature parameters of the heat dissipation part to the controller. For example stm32f103, the controller controls the electromagnetic valve 6 to close, controls the storage battery to output electric energy, and supplies power to the ceramic heating plate, so that the temperature of the component is increased.

As an optimization, the system detects the position of the sun, the radiation plate rotates under the action of the push rod to reduce the included angle between the radiation plate and the sunlight, and the radiation plate is guaranteed to radiate heat to the outside efficiently, so that the temperature of the component is reduced.

Fig. 1 shows a schematic structural diagram of a mechanical part of a thermal control device. As shown in fig. 1, the mechanical part includes a thermal insulation system and a heat dissipation system. The heat preservation system comprises a solar cell panel (attached to the outer surface of the radiation plate), a ceramic heating sheet (attached to the evaporation end of the loop heat pipe tightly), a storage battery 3, a temperature sensor and a controller; the heat dissipation system comprises a flat loop heat pipe evaporation end 1, a radiation plate 2 (namely a flat loop heat pipe condensation end), an electromagnetic valve 6, a temperature sensor, a controller and a light searching module. The detailed operation process of the heat preservation and radiation system is described as follows:

the heat dissipation process: when the temperature sensor on the surface of the heat dissipation part detects that the temperature of the heat dissipation part is too high, the electromagnetic valve 6 is automatically opened, the loop heat pipe starts to work, and the heat dissipation part is dissipated by utilizing the loop heat dissipation effect of the heat pipe. Firstly, the heat dissipation part transfers heat to the evaporation end of the loop heat pipe on the surface of the heat dissipation part, and a liquid working medium in the evaporation end absorbs heat and is gasified, and power for pushing the working medium to circulate is generated; the generated steam working medium is collected and heated in the steam channel on the surface of the capillary core and flows into the radiator 2 through a steam pipeline; the superheated steam is radiated in the radiator to dissipate sensible heat and latent heat, and finally condensed into liquid, and the liquid flows back under the action of capillary suction force and is circulated and reciprocated. Meanwhile, the light searching module detects the position of the solar ray, and the radiation plate rotates under the action of the push rod to reduce the included angle between the radiation plate and the sun, so that the temperature of the component is reduced. In addition, in order to prevent the temperature of the radiating component from continuously reducing, when the radiating component radiates to the rated temperature, the electromagnetic valve is closed, the loop heat pipe stops working, and the radiating process stops.

Secondly, a heat preservation process: when the temperature sensor on the surface of the heat dissipation part detects that the temperature of the heat dissipation part is too high, the controller controls the storage battery to output electric energy to supply power for the ceramic heating sheet on the surface of the component. The ceramic heating sheet generates heat after being electrified, and further can heat the heat dissipation part, so that the temperature of the heat dissipation part is increased to a rated working range.

Preferably, the loop heat pipe comprises an evaporation end and a condensation end. The structure and operation of the flat loop heat pipe as the main body of the heat dissipation system are shown in fig. 2 and 3. Fig. 2 is a concrete diagram of a loop heat pipe, and fig. 3 is a basic structure of the loop heat pipe and a working principle diagram thereof.

Preferably, the evaporation end 1 is of a flat plate structure and is tightly attached to a heat dissipation component with a ceramic heating sheet covered on the surface, and the heat is transferred from the heat dissipation component to the evaporation end 1 through the ceramic heating sheet and then circulated to the condensation end 2 of the heat pipe through the evaporation end 1, so that the purpose of heat dissipation is achieved. Compared with the evaporation end of the traditional loop heat pipe, the evaporation end adopted by the device has the following two innovations: the structure of the auxiliary capillary wick chamber 8 is adopted, and the capillary suction function and the liquid backflow function of the traditional heat pipe capillary wick are separated.

As shown in fig. 5, the evaporation end includes a housing. Four cavities are arranged in the shell, namely a steam buffer chamber 12, a capillary core chamber 10, a secondary capillary core chamber 8 and a liquid storage chamber 13. Preferably, the housing is made of stainless steel; the capillary core arranged in the capillary core chamber 10 is a nickel-based capillary core, and can absorb heat from a high-power device and transfer the heat to a working medium, and the working medium is subjected to phase change to take away the heat; a plurality of holes 9 (preferably 3 holes) are drilled at one side of the capillary core to be used as drainage channels and can increase the radial capillary force; the upper surface of the capillary core is provided with a channel, so that liquid ammonia can be conveniently vaporized into saturated vapor and then dissipated. The secondary capillary core chamber 8 is formed by wrapping secondary capillary cores made of stainless steel wire meshes with the preferred aperture of 20 microns around the liquid storage chamber, and the aperture of the secondary capillary cores is smaller than that of the capillary cores. The axial capillary force can be further enhanced, large bubbles of a liquid pipeline in the capillary core can be effectively damaged, reverse heat leakage is reduced, and stable forward operation of the heat pipe is guaranteed. The secondary capillary core is matched with the hole on one side of the main capillary core, so that the reflux liquid working medium can directly enter the front end of the capillary core for evaporation. The liquid storage chamber can ensure that the capillary core is soaked by the liquid working medium all the time, any pretreatment is not needed before starting, the heat load can be directly applied to the evaporator to start the heat pipe, and the liquid storage and supply to the capillary core of the evaporator are ensured. The steam buffer chamber improves the escape rate of the steam from the capillary core, can balance the diffusion rate of the steam, reduces the diffusion resistance of the steam and leads the steam to be diffused stably.

Preferably, the length of the pores 9 of the capillary wick becomes gradually shorter from the middle position to the peripheral position of the capillary wick. Through a large amount of numerical simulation and experimental research, the length of the hole 9 for arranging the capillary core is gradually shortened, so that the stable forward effect of the heat pipe is better, and the technical effect can be improved by 8-10%. The above empirical formula is also the result of a great deal of experimental research in the present application and is an invention point of the present application, and is not common knowledge in the field.

Further preferably, the width of the gradually shortened pores 9 of the capillary wick is larger from the middle position to the peripheral position of the capillary wick. Through a large amount of numerical simulation and experimental research, the stable forward effect of the heat pipe can be optimized through the arrangement. The above empirical formula is also the result of a great deal of experimental research in the present application and is an invention point of the present application, and is not common knowledge in the field.

According to the method, an optimal capillary core length distribution relation optimization formula is found through a large amount of researches.

The shell is circular structure, and the internal diameter of shell is 2R, and the length of the hole 9 of the capillary core of shell center department is L, then the length L law of the hole 9 of the capillary core of distance R position apart from the center is as follows: l ═ b × L-c × L (R/R)^aWherein a, b and c are coefficients, and the following requirements are met:

1.082<a<1.109,0.99<b<1.01，0.358<c<0.363。

more preferably, a is 1.096, b is 1, and c is 0.361.

The above empirical formula is also the result of a lot of experimental studies, and is an optimized structure of the length distribution of the pores 9 of the capillary wick, which is also an invention point of the present application, and is not common knowledge in the field. Preferably, the area of the through holes of the pores 9 of the capillary wick gradually decreases from the middle position to the peripheral position of the capillary wick.

Further preferably, the width of the capillary wick holes 9 gradually decreases from the middle position to the peripheral position of the capillary wick, and the width increases. The technical effect is seen in the previous relationship of the variation of the length of the pores 9 of the capillary wick.

The shell is circular structure, and the internal diameter of shell is 2R, and the area of the hole 9 of the capillary core of shell center department is S, then the area S law as follows apart from the hole 9 of the capillary core of center distance for the R position:

s＝b*S-c*S*(s/S)^awherein a, b and c are coefficients, and the following requirements are met:

1.085<a<1.113,0.99<b<1.01，0.347<c<0.359。

more preferably, a is 1.099, b is 1, and c is 0.353.

The above empirical formula is also the result of a lot of experimental studies, and is an optimized structure of the area distribution of the pores 9 of the capillary wick, which is also an invention point of the present application, and is not common knowledge in the field.

An evaporation end working process: the liquid working medium starts from the liquid storage chamber and enters the liquid main channel in the capillary core through the secondary capillary core, so that the liquid is uniformly supplied to the capillary core, and the capillary core is always in an infiltration state. The working medium absorbs heat on the outer surface of the capillary core to evaporate, and the generated steam flows out of the steam channel and enters the steam pipeline and then enters the steam buffer chamber. In the process, the capillary core provides power for driving the working medium to circulate.

The invention arranges the secondary capillary core, and the aperture of the secondary capillary core is smaller than that of the capillary core. Compared with the existing loop heat pipe, the axial capillary force can be enhanced, the reverse heat leakage is reduced, and the large bubbles in the liquid pipeline are damaged. The principle is as follows: the secondary capillary wick with high mesh number can increase the capillary force to a certain extent because the pore diameter is very small, thereby enhancing the suction capacity; in the process of reverse operation, the minor capillary core with small aperture can also crush bubbles, thereby filtering certain bubbles and reducing reverse heat leakage.

Fig. 5 shows the specific structure of the four chambers of the housing, from right to left are a gas buffer chamber, a capillary core chamber, an auxiliary capillary core chamber, and a liquid storage chamber, when in normal operation, liquid enters from the right end, gas exits from the left end, the side hole is a filling interface, and liquid working medium can be filled into the loop heat pipe through the interface.

Preferably, the condensation end 2 is mainly provided with a radiator and adopts a structure form that a condensation pipeline is embedded into a condenser plate for heat dissipation. In order to better optimize and improve the performance of the condensation end, the condensation end of the device has the following two innovations: the design of the heat pipe radiator is adopted, and the sandwich honeycomb plate is newly adopted in the structural design of the radiator and is filled with the graphene foam copper.

One end of the radiator is fixed, and the other end of the radiator can be pushed by the push rod to rotate and timely change the inclination angle according to different states of satellite flight, so that the direct radiation of the sun is reduced. The radiator comprises radiation panel and solar panel, and solar panel pastes in the radiator outside, has excellent heat-resisting stability and good resistant irradiation stability. Meanwhile, the radiation plate and the solar panel are attached through the aluminum silicate fiber paper, so that heat transfer can be effectively blocked. Through above-mentioned structure for solar panel absorbs solar energy to the sunny side, satisfies the energy of satellite operation, and the radiation panel sets up at the sunny side of the back, outwards dispels the heat through the radiation panel. The structure enables heat absorption and heat release to be an integral structure, and the heat absorption and heat release are isolated through the heat insulation piece, so that the integral structure is compact, and the arrangement space is reduced. The inner side of the radiator of the invention has no attachments, and the radiator directly radiates heat outwards, thereby improving the radiating efficiency.

The overall section view of the radiator is shown in fig. 6, which sequentially comprises from top to bottom: solar panel 20, aluminium silicate fibre paper 21 (insulating part), upper honeycomb panel 14, condensation line 23, radiant panel edge encapsulation 24, lower honeycomb panel 15.

Preferably, the heat dissipation structure of the radiation plate adopts a sandwich honeycomb plate design, and as shown in fig. 7, the structure of the radiation plate 2 is as follows from top to bottom: an upper honeycomb panel 14, a loop conduit (condenser end 18), and a lower honeycomb panel 16. Light weight, strong impact resistance and suitability for working at high temperature. The honeycomb plate is made of aluminum alloy, and the honeycomb design can reduce the weight of the radiator and enhance the antigravity performance of the radiator; the cellular board is filled with the graphene foam copper 17, so that the contact area of the condensation pipeline and the cellular board can be increased, and the transfer of heat from the loop to the radiator is accelerated. According to fig. 7, a loop pipe is inserted in the graphene copper foam between the upper and lower honeycomb plates. The working medium in the loop pipeline transfers heat to the radiator from the part needing heat dissipation, and the upper honeycomb plate and the lower honeycomb plate transfer the heat in the loop heat pipe to the outer space through heat radiation, so that the heat dissipation process of the heat dissipation part is completed.

In the current aerospace thermal control systems at home and abroad, the problem of heat preservation of heat dissipation parts in a deep-cold outer space environment is rarely involved. Therefore, the device fully considers the problem that the radiating component normally works under the condition that the ambient temperature of the back and the shadow side of the spacecraft is extremely low while ensuring the effective radiation of the small spacecraft. Figure 8 shows a schematic diagram of the insulation system. The heat preservation system of the device innovatively adopts the solar panel to collect and convert energy, and the ceramic heating sheet transfers heat to the heat dissipation part.

The ceramic heating sheet with high heat transfer property covers the surface of the heat dissipation part, so that heat flow conduction can be accelerated during heat dissipation, and the heat dissipation part can be heated at a lower ambient temperature; the solar panel is attached to the outer side of the radiation plate, solar energy is converted into electric energy to be stored in the storage battery, and when the temperature of the heat dissipation part detected by the temperature sensor is lower than a normal working temperature range, the storage battery box supplies power to the ceramic heating sheet to provide heat for the ceramic heating sheet, so that the heat dissipation part can always operate within a normal temperature range; when the temperature of the heat dissipation part detected by the temperature sensor is higher than the normal working temperature range, the power is cut off between the storage battery box and the ceramic heating sheet.

Preferably, the condensation end of the loop heat pipe provides heat energy for the storage battery to be converted into electric energy to be stored in the storage battery.

As an improvement, the invention also provides an optimal calculation algorithm of the included angle of the radiation plate.

Preferably, the optimum tilt angle of the radiation plate is calculated as follows:

from the near-earth space to the interplanetary space, the satellite receives an out-of-space heat flow that is primarily solar radiation, followed by thermal radiation from the earth, the moon, and the satellites and their reflection of the solar radiation. When the heat transfer efficiency of the heat pipe is constant, the working efficiency of the whole thermal control system is greatly dependent on the heat absorption and dissipation conditions of the condensation end (the radiation plate and the solar panel) in space.

For engineering application and simplified calculation, the earth can be regarded as an absolute blackbody of about 250K by assuming that the spatial distribution of the earth infrared is diffuse and following Lambert cosine law, and adopting an average value in calculation.

When the temperature of the evaporation end is kept constant, the heat dissipation efficiency of the evaporation end is equal. Namely:

(1-η)cosβ×α_s×S+(1-η)α_s×E_r×Φ₂+αs×E_e×Φ₃＝α_s×σ×T⁴+ε×σ×T⁴ (1)

TABLE 3 related symbols and meanings

Therefore, the proper sun-facing and ground inclination angle can be determined according to the rated working temperature of the instrument, and the purpose of intelligent temperature control is achieved. The optimal angle calculation formula of the radiation plate is as follows:

the optimum angle of the radiation plate refers to the optimum angle between the normal of the radiation plate and the solar rays. Under the angle position, the heat dissipation efficiency of the radiation plate can be fully ensured, and the temperature rise of the radiation plate and the reduction of the overall heat dissipation efficiency of the device caused by the overlarge area of the sunlight directly irradiating the radiation plate are prevented; in addition, the theoretical optimal angle can meet the normal heat dissipation requirement of the radiator, and meanwhile, the solar panel can be ensured to receive enough illumination intensity so as to ensure sufficient energy storage.

Wherein:

beta: dip angle (solar panel normal and sun ray included angle)

α_s: solar absorption of solar panels, as determined by the solar panelNumber, in the examples, 0.85

δ: black body radiation constant, 5.67 x 10^-8

T: temperature (component requirement), minimum value in heat dissipation and maximum value in heat preservation in the embodiment

s: solar constant, 1367

Eta: the photoelectric conversion efficiency of the solar panel is constant after being selected according to a constant determined by the solar panel, and 20 percent is taken in the embodiment

Epsilon: emissivity of the radiation plate is 0.34 in the embodiment

Taking a geostationary satellite as an example, the emissivity epsilon is 0.34; the solar panel adopts a solar cell with a light trapping structure, and the solar absorptivity alpha of the solar cell_sWhen the conversion rate is 0.85 percent, the photoelectric conversion efficiency is 20 percent; the normal working temperature of the heat dissipation part is 26.85 ℃, namely 300K. Since high orbit satellites are only affected by solar radiation, the self-radiation and reflected heat of the earth are negligible, and therefore:

(1-η)cosβ×α_s×S＝α_s×σ×T⁴+ε×σ×T⁴ (2)

i.e. β ═ arccos (7.259 × 10)^-11×T⁴)

The solution is β 54 °, i.e. the optimum angle between the solar panel normal and the sunlight is 54 °.

In order to effectively realize two functions of heat dissipation and heat preservation, two working modes of manual control and automatic control are set in the aspect of control. The two working modes are both manually controlled and can be freely switched.

The manual control means that the operator adjusts the included angle between the radiator and the sunlight and the on-off state of the electromagnetic valve. An operator can send out corresponding instructions according to real-time data, index parameters and the like of satellite flight, and the instructions are transmitted to the control center through remote communication, and finally the control center controls the machine to make corresponding changes. The automatic control means that a control system of the device automatically adjusts the working state of the mechanical device to make corresponding changes according to the angle of sunlight, the position of a satellite, the working temperature of components and the like.

In the device, the solar panel and the radiation plate are pushed by the push rod to rotate and control the working state of the loop heat pipe through the electromagnetic valve; in addition, the following control parts are also provided: the relay can drive the push rod to move; the steering engine enables the light searching module to rotate, and the light searching module can realize the light following of the solar panel; the temperature sensor with the model number of DS18B20, which is positioned in the spacecraft, can monitor the temperature change of the heat dissipation part in real time; meanwhile, stm32f103 functions as a control center as a control chip.

In the control method, the design aims at the actual thermal control situation when the satellite operates, combines the requirements in the aspect of control, and originally provides a control formula of the angle between the normal line of the radiation plate and sunlight when the temperature of the component is in a rated working range and the temperature of the component is higher than the evaporation end of the heat pipe:

the angle control formula determines the angle of rotation required by the radiation plate when the radiation plate rotates from the current position to the theoretical optimal inclination angle position of the radiation plate, wherein:

e_n: current component temperature-current heat pipe evaporation end temperature

e_n-1: temperature of previous component-temperature of evaporation end of previous heat pipe

K_P: constant of proportionality, preferably 0.04

K_I: integration constant, preferably 0.005

K_D: differential constant, preferably 0.5

The three constants of proportion, integration and differentiation can be adjusted according to actual conditions, the sampling frequency of the temperature can influence the values of the three constants, and the integration part can be removed according to specific conditions. In summary, the value ranges of the three constants are: k_PMaximum not exceeding 0.15; k_IThe maximum can not exceed 0.03; k_DThe maximum value cannot exceed 1.00. In addition, for the position of accurate positioning sunlight, rationally regulate and control the contained angle between radiation board and the sunlight, this device designs as follows the sun system:

the solar tracking system is shown in fig. 10-2. The sun tracking system consists of two parts of circuit comprising shading plate and photoresistor. The structure is shown in figure 10-2:

in fig. 10-2, two sides are provided with probes, and a photoresistor is arranged in the probes. The shading plate is positioned at the upper part of the probe. In the sun tracking system, the probe is placed upwards, and a light shielding plate is arranged above the probe and can be adjusted according to the intensity of light rays. If the sun's rays shine from the left, the left probe can receive the rays and the right probe does not, thus returning a signal for turning to the left. Conversely, if the sun shines from the right, a signal of turning to the right is returned. In addition, if the sun shines from top to bottom, and no light is received by the left and right sides, a stationary signal will be returned.

Because the device can only be used for vertically following the sun, if the radiation plate and the sunlight are required to form a certain angle, the steering engine can be used for driving the device so as to change the angle between the device and the radiation plate and achieve the purpose that the radiation plate and the sunlight form a certain angle.

The complete workflow of the device is shown in fig. 11. The heat dissipation and the heat preservation are two important components of the system work, and the specific work flows are respectively described as follows:

the heat dissipation process: when the temperature of the heat dissipation part exceeds a rated temperature range due to continuous work or external strong solar radiation, the electromagnetic valve is automatically opened, the heat dissipation device is started to dissipate heat of the heat dissipation part, and the working efficiency of the heat pipe is improved; meanwhile, the system detects the position of the sun, and the radiation plate rotates under the action of the push rod to reduce the included angle between the radiation plate and the sun, so that the temperature of the component is reduced.

Secondly, a heat preservation process: when the temperature of the heat dissipation part is lower than the rated temperature range due to the extremely low environmental temperature of the back and back surface, the ceramic heating sheet is started, and the electric energy converted by the solar panel is utilized to provide energy for the ceramic heating sheet, so that the temperature of the element is increased.

In addition, when the temperature of the component is in the rated working range, the temperature of the component and the temperature of the evaporation end are detected and compared. If the temperature of the component is higher than that of the evaporation end, the system detects the position of the sun, increases the included angle between the radiation plate and the sun, and reduces the working efficiency of the heat pipe to prevent the temperature of the heat pipe from further reducing; otherwise, the loop heat pipe automatically stops working.

In order to realize energy-saving and emission-reducing benefits, the system is mainly designed in an energy-saving mode in the following two aspects, and the energy-saving characteristic of the device is displayed more intuitively through calculation.

Honeycomb panel structure of radiator. Through density calculation, the weight of the structure of the honeycomb plate is reduced by about 9.2kg compared with that of a solid aluminum alloy heat dissipation plate with the same volume, and the energy consumption required by satellite launching and operation can be effectively reduced due to the reduction of the weight.

② the composite design of solar energy plate/radiation plate. The energy required by the heat preservation and heating process of the heat dissipation part in the satellite is completely provided by solar energy, so that the extra energy burden of the satellite can be reduced. The electric power it generates is:

η×cosβ×A×S×＝136.7×cosβ (3)

wherein: is the angle between the normal of the solar panel and the sun ray.

In the development and implementation process of the project, the capillary wick suction experiment and the capillary wick performance test experiment ensure the quality of the capillary wick and provide theoretical support for the efficient operation of the device. Meanwhile, hardware equipment such as a vacuumizing perfusion device, a vacuum hot-pressing sintering furnace and the like are also used in the preparation process to complete the preparation of the high-performance loop heat pipe.

As a core component of the loop heat pipe, the capillary wick is originally designed in the preparation process of the capillary wick, so that the capillary wick can meet the requirements of severe working environment and strict electronic heat dissipation, as shown in figure 12.

Compared with the existing capillary core preparation technology, the preparation technology characteristics and the advantages and effects of the capillary core in the design are shown as follows: firstly, cold pressing sintering of a capillary core is adopted. During cold-pressing sintering, the porosity and permeability of the capillary core are increased along with the increase of the proportion of the pore-forming agent; when the pore-forming agent is 30%, the suction performance of the capillary core is extremely high. ② a capillary core with the inner diameter of 8mm is adopted. Tests show that the capillary wick with the inner diameter of 8mm has the best suction performance in the capillary wick with the outer diameter of 20mm and the length of 100 mm. And thirdly, the self-made liquid ammonia working medium vacuumizing and filling platform is used for vacuumizing and filling the loop heat pipe. The loop heat pipe stability is further improved.

The specific process steps are as follows:

1) and (4) proportioning the powder. The design selects nickel powder with the granularity of 2 mu m as a main material of the capillary core, and adds NaCl with the purity of 99.5 percent as a pore-forming agent to prepare the dual-pore-diameter capillary core. Firstly, grinding Nacl particles by a ball mill (periodic positive and negative rotation ball milling is adopted, wherein the positive and negative rotation time is 45min, the interval time is 5min, and the total ball milling time is 6 h); the particle size of the NaCl after ball milling is mainly distributed in 200-400 meshes, while the NaCl particles below 400 meshes are extremely small, and the NaCl powder with the particle size of 48 mu m (300-400 meshes) is screened out through vibration; and finally, uniformly mixing the nickel powder and the Nacl powder by a ball mill, and then putting the mixture into a drying box for drying.

2) And (5) cold press molding. The powder was press-molded by a press machine with a pressure of 50kN and a pressure increasing speed of 200N/s.

3) And (5) sintering the capillary core. The vacuum hot-pressing sintering furnace selected preferably for the experiment is ZT-40-20Y.

4) And (4) ultrasonic cleaning. After sintering, the Nacl particles in the capillary core are dissolved by ultrasonic cleaning to form a gap, so that a dual-pore-diameter structure is obtained.

The suction performance of the capillary core is judged most intuitively by observing the rising height of the working medium in the capillary core, but the height of the working medium in the capillary core is difficult to observe, so that the suction capacity of the capillary core is determined by measuring the suction quality of the capillary core in an experiment. The graph of the pumping experiment is shown in FIG. 13

The experimental results show that: 1. the suction performance of the capillary core tends to increase and then decrease along with the increase of the pore-forming agent ratio. By

The experiment shows that: the heat transfer power of a single heat pipe can reach 400W, and the heat transfer performance is excellent.

The loop heat pipe preparation process adopts a filling device and a sintering furnace. The vacuumizing filling device can realize high-vacuum quick filling and automatically and accurately control the filling amount, so that the heat transfer power and the limit power of the heat pipe are effectively improved, and the discharge and waste of filling working media can be obviously reduced; the vacuum hot-pressing sintering furnace can perform hot-pressing sintering on the capillary core under a vacuum condition, can effectively remove vapor in the tiny air holes, and enables the pore diameter inside the capillary core to be fine and more uniformly distributed.

When the composite thermal control system works, the flat-plate loop heat pipe is attached to a component needing heat dissipation, and the solar panel covers the outer side of the radiation plate to absorb solar energy in real time and convert the solar energy into electric energy to be stored in the storage battery. When the temperature is higher, working media inside the flat-plate loop heat pipe attached to the surface of the part needing heat dissipation are heated to be evaporated on the outer surface of the capillary core, and generated steam flows into a steam pipeline and then enters a condenser to be condensed into liquid and is supercooled; and the return liquid enters the liquid trunk through the liquid pipeline to supply the capillary core of the evaporator, and the circulation is repeated. When the temperature is lower, the storage battery can supply power to the ceramic heating sheet and convert electric energy into heat energy so as to supply heat for the heat dissipation component. Considering the special working environment of the composite thermal control system, the test is difficult to be developed in the outer space, so that a space three-dimensional test bed with higher simulation degree is adopted.

In the whole working period of the device, the power required by the system heat dissipation process is completely provided by the capillary force generated by the nickel-based capillary core, and no external power is required; the energy required by the heat preservation process of the system is completely provided by solar energy, and the redundant electric energy converted by the solar energy can be further used by the spacecraft. The whole system is closely matched with each part, so that zero energy consumption and high efficiency are really achieved, and the problems of difficulty in thermal control, low efficiency and high energy consumption of the small spacecraft can be effectively solved.

The invention has the following innovations:

1) the heat pipe radiator heat dissipation system and the solar electric heating system are innovatively combined, and the heat dissipation and heat preservation effects with zero energy consumption can be integrally realized.

2) The capillary suction function and the liquid backflow function of the traditional heat pipe capillary wick are separated. The heat transfer distance is obviously improved, and the farthest distance can reach 10 m. The antigravity capability is also obviously enhanced, and the antigravity height can reach 5m at most. The outstanding performance solves the problem of limitation of the using direction and length of the traditional heat pipe, and has extremely high applicability in space.

3) And (5) optimizing the structure of the heat pipe. The auxiliary capillary wick is added into the liquid storage chamber of the heat pipe and inserted into the capillary wick, so that liquid ammonia can rapidly enter the capillary wick, the contact area of the liquid ammonia and the capillary wick is enlarged, the axial capillary force of a loop is enhanced, large air bubbles of a liquid pipeline in the capillary wick can be effectively reduced, reverse heat leakage is reduced, stable and forward operation of the heat pipe is ensured, and the capillary suction speed of the heat pipe is increased to 0.6 g/s.

4) The structure of the radiation plate is optimized. The device adopts the design of the sandwich cellular board radiator, the structure of the cellular board has the remarkable advantage of light weight, the energy consumption caused by the lifting and running of the satellite can be effectively reduced, and the shock resistance is stronger. Graphene foam copper is filled in a cavity through which a loop pipeline passes in the cellular board, so that the contact area between the loop heat pipe and the radiator can be increased by 346.4%.

The invention has the following benefits of energy conservation and emission reduction:

1) and the heat dissipation and heat preservation system has zero energy consumption. The heat dissipation system is spontaneously completed by means of the suction and reflux functions of the heat pipe without any energy input; the heat preservation system absorbs solar energy and converts the solar energy into electric energy to be stored by means of the solar cell panel on the outer side of the radiation plate, and when the satellite assembly needs to preserve heat, the heat preservation effect is achieved by supplying power to the heating sheet. The whole system gets rid of the dependence on external energy, and compared with other heat dissipation devices, the unit thermal control system can save 86400KJ of energy at most every day and night.

2) The heat pipe has high heat transfer efficiency. The device adopts a nickel-based capillary core ammonia working medium loop heat pipe, wherein the porosity of the nickel-based capillary core is up to more than 60%, the capillary suction speed is up to 0.6g/s, the heat resistance of the heat pipe can be stabilized at 0.15 +/-0.02 ℃/W under the charging quantity of 60%, the heat resistance is lower than the current general range of 0.18-0.32 ℃/W in the market, the overall heat transfer power can be up to 400W, the ultimate power is improved by 100W compared with that of a common heat pipe, and the overall heat transfer performance is greatly improved.

3) The radiating plate has high radiating efficiency. The radiating plate enables the radiating efficiency of the system to be obviously improved by increasing the radiating area. According to calculation, in the radiation plateThe area of the embedded pipe wall is about 0.224m²The radiating plate per unit area can improve the heat dissipation area by at least 346.4%. In addition, the weight of the radiant panel per unit area is reduced by about 9.2kg compared to the conventional cold plate, which saves 68.15% of alloy material. The radiating plate can improve the heat dissipation area by at least 346.4%.

Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.