High-precision spaceborne temperature fixed point reproduction device

Abstract

The invention provides a high-precision spaceborne temperature fixed point reproduction device, and the device comprises a phase change material which has a fixed melting point as a reference temperature; a fixed point container containing a phase change material; the inner layer coating structure coats the fixed point container and performs heat insulation; the outer-layer coating structure coats the inner-layer coating structure and is used for insulating heat; and the force and heat connecting piece is connected with the inner-layer coating structure and the outer-layer coating structure to form a unique heat conduction channel from the inner layer to the outer layer. Cooling and heating are achieved through the cold black cosmic space radiation environment and the electric heater, only single-point active temperature control is needed, and the system is simple in structure, good in reliability, high in temperature uniformity, small in mass and size and low in economic cost.

Description

Technical Field

[0001] This invention relates to the field of precision temperature measurement technology for spacecraft, and in particular to a high-precision spaceborne temperature fixed-point reproduction device. Background Technology

[0002] New-generation spacecraft, exemplified by space gravitational wave detectors, have extremely high requirements for temperature control precision, necessitating the assurance of accurate temperature measurements. To eliminate temperature measurement deviations caused by factors such as errors in temperature measurement circuits and the time-dependent drift of temperature sensor performance, a precise reference temperature source needs to be installed on the spacecraft as a temperature scale.

[0003] Currently, the most accurate reference temperature is given by the characteristic temperature of the material. Some materials have stable melting points, meaning their solidification and melting processes correspond to fixed temperatures. The internationally accepted ITS-90 temperature scale defines a fixed temperature point based on the phase transition temperatures of materials such as water and gallium, and provides the temperature value of this fixed point as the primary reference for defining the temperature scale. To reproduce this temperature point, it is necessary to repeatedly melt and freeze the phase change material with a fixed melting point through temperature control, using the temperature during the melting process as the reference temperature for temperature calibration and standardization. The temperature control device needs to achieve temporal stability and spatial uniformity of the phase change material temperature better than 10 mK to ensure the accuracy of the temperature standard.

[0004] Existing literature only explicitly reports temperature reproduction technology in ground-based applications. This type of technology is mainly divided into two categories: one is to move a fixed-point container containing phase change material into a uniform cold / hot environment to achieve freezing and melting; the other is to use heating / cooling equipment to change the thermal environment of the fixed-point container to achieve cooling and heating.

[0005] The first type of technology requires a motion device and a uniform, controllable hot and cold environment, which is not applicable to current aerospace applications. The second type of technology requires both heating and cooling equipment. Due to mass and volume constraints, only the TEC (thermoelectric thermoelectric cooler) solution is feasible for aerospace applications. This type of solution requires multiple TEC temperature control points, and additional heat dissipation channels and control algorithms need to be designed for each TEC, resulting in a complex system, lower reliability, and susceptibility to secondary thermal interference. Furthermore, due to the limitations of the above temperature control methods, the temperature uniformity of phase change materials is typically only on the order of 10 mK. Summary of the Invention

[0006] The purpose of this invention is to achieve on-orbit reproduction of fixed temperature points on spacecraft under the principles of high precision, high reliability, and low resource consumption, thus meeting the requirements of temperature calibration and other aspects of precision temperature control systems. To solve the above problems, this invention provides a high-precision spaceborne fixed-point temperature reproduction device, characterized by comprising:

[0007] Phase change materials have a fixed melting point as a reference temperature;

[0008] A fixed-point container configured to contain the phase change material;

[0009] An inner covering structure is configured to cover the fixed-point container and provide thermal conductivity and insulation.

[0010] An outer covering structure configured to cover the inner covering structure and provide thermal conductivity and insulation; and

[0011] A thermal connector that connects the inner and outer covering structures to form a heat conduction channel from the inner to the outer layer.

[0012] In one embodiment of the present invention, the covering structure includes:

[0013] Thermally conductive coating structure, the material of which is metal or alloy; and

[0014] The thermal insulation covering structure is made of multi-layer thermal insulation components or aerogel.

[0015] In another embodiment of the present invention, the thermal connector connects the inner thermally conductive coating structure and the outer thermally conductive coating structure.

[0016] In another embodiment of the present invention, a temperature sensor and an electric heater are arranged on the force-thermal connector, which are used to perform single-point temperature control on the force-thermal connector in order to perform global temperature control on the fixed-point container.

[0017] In another embodiment of the present invention, the outer heat insulation covering structure is not a complete covering, and the exposed heat-conducting covering structure directly radiates heat to the cold black space environment.

[0018] In another embodiment of the present invention, the exposed thermally conductive covering structure is covered with a radiation shielding film, which is used to reduce radiation power, thereby reducing the heat dissipation power and heat replenishment requirements of the device.

[0019] In another embodiment of the invention, the fixed-point container includes a shell and a thermometer trap, the thermometer trap being used to house a temperature sensor and to calibrate and standardize its temperature.

[0020] In another embodiment of the present invention, both the inner and outer layer covering structures have wire-through holes for leading out internal wires. After the wires pass through, the wire-through holes are sealed with heat-insulating material to reduce the impact of heat leakage on the internal temperature field.

[0021] In another embodiment of the present invention, the infrared emissivity of the surface of the heat insulation covering structure is less than 0.1, and the solar radiation absorptivity is less than 0.2.

[0022] In another embodiment of the present invention, the phase change material is water, metal or alloy.

[0023] This invention employs a multi-layer thermally conductive / insulating coating design, with a thermally conductive connector serving as the sole thermal channel between the inner and outer coating structures, and utilizes the thermal environment of the cold black space to achieve cooling and freezing.

[0024] Among them, the alternating thermal conduction / insulation coating design efficiently achieves temperature uniformity inside the device under uneven external heat flow; the single thermal conduction channel design of the thermal connector transforms the global temperature control problem of the fixed-point container into the temperature control problem of a single external component, reducing the number of active temperature control points and system complexity, and improving the stability and uniformity of temperature control; while the use of the cold black space environment for cooling reduces the need for active cooling equipment, further simplifies the system, and improves reliability and economy. Attached Figure Description

[0025] Figure 1 A structural diagram of a high-precision spaceborne temperature fixed-point reproduction device according to an embodiment of the present invention is shown;

[0026] Figure 2 A schematic diagram of the installation of the melting point reproduction device in one embodiment of the present invention is shown;

[0027] Figure 3 This illustrates the temperature change within the thermometer trap during heating in one embodiment of the invention; and

[0028] Figure 4 A schematic diagram of temperature uniformity during temperature control is shown in one embodiment of the present invention;

[0029] The following are the labels: 1-outer shell; 2-thermometer trap; 3-phase change material; 4-inner thermally conductive coating structure; 5-inner thermal insulation coating structure; 6-outer thermally conductive coating structure; 7-outer thermal insulation coating structure; 8-external radiating surface; 9-thermal connector; 10-temperature sensor; 11-heater; 12-radiation shielding film; 13-wiring hole. Detailed Implementation

[0030] In the following description, the invention is described with reference to various embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more specific details or with other alternatives and / or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail so as not to obscure the inventive points of the invention. Similarly, for illustrative purposes, specific quantities, materials, and configurations are set forth to provide a comprehensive understanding of embodiments of the invention. However, the invention is not limited to these specific details.

[0031] Furthermore, it should be understood that the embodiments shown in the accompanying drawings are illustrative and not necessarily drawn to scale. In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to the same embodiment in all instances.

[0033] Figure 1 A structural diagram of a high-precision spaceborne temperature fixed-point reproduction device according to an embodiment of the present invention is shown.

[0034] like Figure 1 As shown, the present invention provides a high-precision spaceborne temperature fixed-point reproduction device, comprising:

[0035] A fixed-point container includes a housing 1 and a thermometer trap 2, wherein the thermometer trap 2 is used to house a temperature sensor and calibrate and standardize its temperature.

[0036] Phase change material 3 has a stable melting point temperature, and its optional materials are water, metals and alloys. This invention does not impose too many restrictions on it.

[0037] The inner layer covering structure includes an inner thermally conductive covering structure 4 and an inner thermally insulating covering structure 5, wherein the thermally conductive covering material is a metal or alloy, and the thermally insulating covering material is a multi-layer thermally insulating component or aerogel.

[0038] The outer covering structure includes an outer thermally conductive covering structure 6 and an outer thermally insulating covering structure 7. The outer thermally insulating covering structure 6 is not a complete covering, and the exposed thermally conductive covering structure forms an external radiation surface 8, which can directly radiate heat to the cold black space environment.

[0039] The thermal connector 9 connects the inner thermal conductive covering structure 4 and the outer thermal conductive covering structure 6, forming a unique thermal conductive channel from the inner layer to the outer layer.

[0040] Temperature sensor 10 and electric heater 11 are arranged on the force-heat connector 9 for single-point temperature control of the force-heat connector 9, thereby indirectly realizing full-range temperature control of the fixed-point container.

[0041] A radiation shielding film 12 is attached to the external radiation surface 8 to reduce radiation power, thereby reducing the heat dissipation power and heat replenishment requirements of the device.

[0042] The wire hole 13 is provided on both the inner and outer covering structures to lead out the internal wires. After the wires are passed through, they are sealed with heat insulation material to reduce the impact of heat leakage on the internal temperature field.

[0043] The working principle of the present invention will now be described in detail according to another embodiment of the present invention.

[0044] In this embodiment, the phase change material 3 is selected as high-purity gallium, with a melting point of 29.7646℃. The outer shell 1 of the fixed-point container is a stainless steel shell with an outer diameter of 32mm, a height of 60mm, and a thickness of 1mm. The internal thermometer trap 2 is made of polytetrafluoroethylene. The inner thermally conductive coating structure 4 is made of copper with a thickness of 1mm and a thermal conductivity of 400W / m·K. The thermally conductive connector 9 and the outer thermally conductive coating structure 6 are made of aluminum alloy with a thermal conductivity of 150W / m·K and a surface infrared emissivity of 0.1. The radiation shielding film 12 on the exposed part of the aluminum alloy top plate is a thermal control coating with a surface infrared emissivity of 0.8. All the thermal insulation coating materials are selected as multi-layer thermal insulation components with a thickness of 5mm, an equivalent thermal conductivity of 0.004W / m·K, a surface infrared emissivity of 0.05, and a solar absorptivity of 0.15.

[0045] Figure 2 A schematic diagram of the installation of the melting point reproduction device in one embodiment of the present invention is shown.

[0046] like Figure 2 As shown, this invention is installed outside the satellite cabin, minimizing direct sunlight to ensure uniform internal temperature. Its top faces the cold, dark space environment to facilitate radiative heat dissipation. The bottom is thermally insulated from the satellite's outer cabin panel. This device, installed outside the spacecraft cabin, uses an electric heater to melt the phase change material and then freezes it through radiative heat dissipation from the cold, dark space environment. No active cooling equipment is required; only single-point active temperature control is needed.

[0047] Figure 3 The temperature change within the thermometer trap during heating is shown in one embodiment of the present invention.

[0048] like Figure 3 As shown, in the natural initial state, the heater is turned off, and the melting point reproduction device radiates heat to the outside through the exposed aluminum alloy shell, the temperature decreases, and the gallium in the fixed point container freezes from liquid to solid.

[0049] After complete freezing, the heater is activated to stabilize the temperature of the thermally heated connector at 31°C, slightly above the melting point of gallium. At this point, the temperature of the metallic gallium will slowly rise. Figure 3 The rising phase of the temperature curve. Once the temperature of gallium reaches its melting point (29.7646℃), it begins to liquefy and absorb heat, causing the temperature within the thermometer trap to plateau. At this point, the temperature sensor within the thermometer trap can be calibrated based on the temperature within the trap.

[0050] As heating continues, gallium transitions from a solid-liquid coexistence to a completely liquid state, eliminating the endothermic phase transition effect. The temperature within the thermometer trap begins to rise rapidly, marking the end of the temperature plateau. At this point, the heater needs to be shut off. As the exposed aluminum alloy casing radiates heat outwards, the liquid gallium freezes into solid gallium, facilitating reheating to reproduce the temperature.

[0051] Figure 4 A schematic diagram of temperature uniformity during temperature control is shown in one embodiment of the present invention.

[0052] In this embodiment, the above Figure 3 The numerical values ​​of the operating conditions in the illustrated embodiment were used to design a simulation model for simulation verification. The overall mass of the device (including gallium metal) is 506g, and its envelope size is a cylinder with a diameter of 70mm and a height of 91mm. Figure 4 As shown, under extreme conditions where the melting point reproduction device is directly exposed to sunlight on one side, the surface temperature difference of its outer heat insulation coating material is as high as 350K or more, while the maximum temperature difference in the gallium metal inside is only 0.19mK. The temperature uniformity is more than one order of magnitude higher than that of the existing technology.

[0053] In summary, this invention exhibits extremely high temperature stability and uniformity, meeting the precise temperature control requirements for melting point reproduction. Its key principles lie in two aspects. First, both the inner and outer coating structures employ an alternating insulation / thermal conductivity design. This alternating structure is highly beneficial for forming a heat conduction path with strong insulation in the thickness direction and high thermal conductivity in the planar direction, thereby ensuring internal temperature uniformity under uneven external heat flow. Second, a force-thermal connector is set between the inner and outer coating structures as the sole thermal channel. This design allows for single-point temperature control of the force-thermal connector, thereby achieving full-range temperature control of the fixed-point container, significantly reducing the number of active temperature control points and the difficulty of temperature control. When the temperature stability of the force-thermal connector is good, the temperature stability and uniformity of the fixed-point container can also be guaranteed.

[0054] Although various embodiments of the invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made without departing from the spirit and scope of the invention. Therefore, the breadth and scope of the invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined solely by the appended claims and their equivalents.

Claims

1. A high-precision spaceborne temperature fixed-point reproduction device, characterized in that, include: Phase change materials have a fixed melting point as a reference temperature; A fixed-point container configured to contain the phase change material; An inner covering structure is configured to cover the fixed-point container and provide thermal conductivity and insulation. An outer covering structure is configured to cover the inner covering structure and provide thermal conductivity and insulation; as well as A thermal connector that connects the inner layer covering structure and the outer layer covering structure to form a heat conduction channel from the inner layer to the outer layer.

2. The reproduction device as described in claim 1, characterized in that, The covering structures all include: Thermally conductive coating structure, the material of which is metal or alloy; and The thermal insulation covering structure is made of multi-layer thermal insulation components or aerogel.

3. The reproduction device as described in claim 2, characterized in that, The thermal connector connects the inner thermally conductive coating structure and the outer thermally conductive coating structure.

4. The reproduction device as described in claim 3, characterized in that, The force-thermal connector is equipped with a temperature sensor and an electric heater, which are used to perform single-point temperature control on the force-thermal connector in order to perform global temperature control on the fixed-point container.

5. The reproduction device as described in claim 2, characterized in that, The outer thermal insulation covering structure is not a complete covering, and the exposed thermally conductive covering structure directly radiates heat to the cold, dark space environment.

6. The reproduction device as described in claim 5, characterized in that, The exposed thermally conductive covering structure is covered with a radiation shielding film, which is used to reduce radiation power, thereby reducing the device's heat dissipation power and heat replenishment requirements.

7. The reproduction device as described in claim 1, characterized in that, The fixed-point container includes an outer shell and a thermometer trap, which is used to house a temperature sensor and calibrate and standardize its temperature.

8. The reproduction device as described in claim 1, characterized in that, Both the inner and outer cladding structures have through holes for leading out internal wires. After the wires pass through, the through holes are sealed with heat insulation material to reduce the impact of heat leakage on the internal temperature field.

9. The reproduction device as described in claim 2, characterized in that, The infrared emissivity of the surface of the heat insulation coating structure is less than 0.1, and the solar radiation absorptivity is less than 0.

2.

10. The reproduction device as described in claim 1, characterized in that, The phase change material is water, metal, or alloy.

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