A method for testing a satellite configured with deployable radiators in thermal equilibrium

Abstract

A satellite equivalent heat balance test method for deployable radiators is provided, which analyzes the heat exchange relationship between the deployable radiators and the satellite body by the whole satellite heat analysis mode, so as to serve as the theoretical basis for the heat balance test of the radiators and the satellite body in the partitioned placement; the deployable radiators are connected with the satellite body by the replacement metal hose, so as to ensure the heat transmission capacity of the satellite body to the deployable radiators; the infrared cage of the deployable radiators and the infrared cage of the satellite body are separated by the liquid nitrogen cold plate, so as to ensure that they do not interfere with each other; the heat exchange amount between the deployable radiators and the satellite body is corrected by using the temperature data after the heat balance, and the heat exchange amount is re-applied to the target in the form of heat flow, so as to realize the correction iteration. Thus, the problem that the satellite with deployable radiators is difficult to accurately simulate the external heat flow of the radiators and the adjacent structure plate in the positive sample heat balance test is solved.

Description

Technical Field

[0001] This invention relates to the field of spacecraft thermal control technology, and in particular to a method for testing the equivalent thermal balance of a satellite equipped with a deployable radiator. Background Technology

[0002] The enhanced capabilities of space payloads and the diversification of mission modes have placed higher demands on satellite heat dissipation. Limited by satellite size and heat transfer efficiency, heat dissipation capacity is increasingly becoming a crucial factor constraining satellite missions. With limited increases in satellite launch envelope size, deployable radiators can significantly increase the effective heat dissipation area of ​​the satellite, becoming an important development direction in the thermal control design of high-power satellites.

[0003] The deployable radiator is folded up and fixed to the satellite structure plate before launch, and unlocked and deployed after entering orbit. The deployed radiator is connected to the satellite body through a flexible pipeline. The fluid loop transfers the heat of the satellite body to the radiator, and then dissipates the heat to the cold space through thermal radiation.

[0004] Deployable radiators and the satellite body have complex relationships regarding external heat flow shielding and radiative heat transfer. Currently, common methods for simulating external heat flow in spacecraft ground-based thermal experiments include the following:

[0005] Simulate using a solar simulator;

[0006] Surface contact electric heater;

[0007] Infrared heating simulates heat flow absorption (e.g., infrared cages, infrared lamp arrays).

[0008] Currently, solar simulation technology in China is not yet mature, and solar simulators are unable to simulate the Earth's infrared heat flow, so this method cannot be used.

[0009] For prototype satellites, the radiator surface and satellite structural plate surface have already been coated with a prototype thermal control coating. Using a surface contact electric heater would damage the coating, so this method cannot be used.

[0010] For prototype satellites equipped with deployable radiators, thermal balance tests can only be conducted using infrared heating to simulate heat flow absorption. However, due to the large size of the deployable radiator, the envelope size of the test container after deployment is critical. Furthermore, the close proximity of the deployable radiator to the satellite body means that simulating external heat flow using infrared cages or infrared lamp arrays inevitably has a significant impact on the other. Therefore, verifying the thermal control design of the prototype satellite through thermal balance tests remains a significant challenge. Summary of the Invention

[0011] To address the challenge of accurately simulating the external heat flow between the radiator and adjacent structural plates in prototype thermal equilibrium tests of satellites equipped with deployable radiators, this disclosure provides an equivalent thermal equilibrium test method. The method includes the following steps:

[0012] (1) Calculate the external heat flow and infrared radiation heat flow.

[0013] A complete thermal analysis model of the entire satellite was established. This model, representing the flight state, includes not only the satellite itself but also large surface components such as the deployable radiator and solar panels. Based on the extraorbital heat flux and the satellite's operational mode, the low-temperature and high-temperature operating conditions for the thermal balance test were determined. The extraorbital heat flux and temperature field of various parts of the satellite, including the deployable radiator, were calculated. Simultaneously, the radiative heat transfer coefficient B of the deployable radiator to adjacent structural plates of the satellite was calculated. i,j The radiative heat transfer coefficient B of the satellite's adjacent structural plates to the deployable radiator j,i Similarly, the radiative heat transfer coefficients between the deployable radiator and the solar panel, and between the satellite structure panel and the solar panel, can be calculated. Since the solar panel is generally not involved in the overall satellite thermal balance test, the infrared heat flux effect of the solar panel on the satellite needs to be added to the simulated external heat flux.

[0014] The deployable radiator absorbs infrared radiation heat flux from adjacent structural panels of the satellite.

[0015]

[0016] The satellite structural panels absorb the infrared radiation heat flux of the deployable radiator.

[0017]

[0018] The solar panel absorbs the infrared radiation heat flux from the deployable radiator.

[0019]

[0020] Infrared radiation heat flux from solar panels to satellite structural panels:

[0021]

[0022] Where Q1~Q4 represent infrared radiation heat flux in W; m, n, and s represent the number of nodes in the deployable radiator, satellite structure plate, and solar panel model, respectively; i, j, and k are the corresponding node numbers; ε represents the surface infrared emissivity, dimensionless; and A represents the area in m². 2 T represents the temperature calculated in the whole-satellite thermal analysis model, in Kelvin (K).

[0023] (2) Calculate the temperature of the heat flow meter

[0024] For satellite structural panels unaffected by the infrared heat flux from deployable radiators and solar panels, the heat flux meter temperature is:

[0025]

[0026] The temperature of the heat flux meter for the satellite structural plate affected by the infrared radiation heat flux from the deployable radiator and solar panels is:

[0027]

[0028] The temperature of the heat flux meter for the deployable radiator affected by the infrared radiation heat flux from the solar panels and satellite structural plates is:

[0029]

[0030] Q s σ is the external heat flux (in W), and σ is the blackbody radiation constant (W / m). 2 .K 4 ).

[0031] (3) External heat flow and temperature measurement

[0032] Several heat flux meters are attached to the radiator and the satellite body to measure the arriving infrared heat flux. Several thermocouples are attached to the radiator and the satellite body to measure the temperature.

[0033] (4) Deployable radiator hoisting design

[0034] The deployable radiator is installed separately from the satellite body. The radiating plate of the deployable radiator has a honeycomb structure, with aluminum alloy embedded blocks at all four edges and M8 screw holes. Using tooling, the deployable radiator is hoisted onto a trapezoidal test support, with the normal to the radiating plate perpendicular to the direction of gravity. This hoisting method not only reduces the horizontal topology of the test system but also facilitates the installation of the infrared cage and cold plate.

[0035] (5) Simulation of external heat flow of deployable radiator

[0036] The deployable radiator has heat dissipation surfaces on both sides. To eliminate the influence of background heat flow, infrared cages are installed on both sides of the radiator. During the heat balance test, the total amount of external heat flow on both sides of the radiator is kept constant, and the external heat flow applied to the infrared cages on both sides is distributed according to the actual background heat flow on both sides.

[0037] (6) Design to eliminate thermal flow interference between test specimens

[0038] A liquid nitrogen cooling plate is designed between the radiator infrared cage and the satellite structural plate infrared cage to eliminate thermal flow interference between the radiator, infrared cage and satellite structural plate.

[0039] (7) Deployable radiator coupled with satellite fluid loop design

[0040] Considering factors such as available space and flow resistance, two flexible metal hoses are fabricated to connect the deployable radiator and the satellite fluid loop piping, establishing a closed fluid loop heat dissipation system. To prevent heat leakage from the metal hoses and subsequent freezing of the working fluid in the fluid loop, electric heating wires are wrapped around the surface of the metal hoses for heating, and multiple layers of insulation are then applied.

[0041] (8) External heat flow correction

[0042] In the thermal equilibrium test, external heat flow is applied to the deployable radiator and satellite structural plate according to the calculated results of external heat flow and formulas (5), (6), and (7). When the radiator and satellite temperatures are in equilibrium, the heat exchange between the radiator and satellite structural plate, Q1 and Q2, is calculated using actual thermocouple temperature measurement data. Based on the deviation of the calculation results, it is determined whether it is necessary to readjust the external heat flow between the radiator and the adjacent structural plate of the satellite.

[0043] Compared with the prior art, the beneficial effects of this disclosure are:

[0044] (1) In the thermal balance test, the radiator and the satellite body are arranged independently in the test container. The radiator installation method is flexible and has little dependence on the space of the test container.

[0045] (2) The radiator and the satellite body are arranged in partitions by liquid nitrogen cold plates. The infrared heating cages of the radiator and the infrared heating cages of the satellite body do not interfere with each other's target heating zones, making the external heat flow simulation more accurate.

[0046] (3) Thermocouples are attached to the radiator and the satellite body to measure the real-time temperature of the thermal balance test. The temperature data and thermal radiation parameters are used to correct and iterate the heat flow exchange between the radiator and the satellite body, so as to make the thermal boundary simulation more accurate. Attached Figure Description

[0047] The above and other objects, features and advantages of this disclosure will become more apparent from the more detailed description of exemplary embodiments of this disclosure taken in conjunction with the accompanying drawings, in which the same reference numerals generally represent the same components.

[0048] Figure 1 This is a schematic diagram of the layout of the radiator and the satellite body during the thermal balance test;

[0049] Figure 2 This is a schematic diagram of the radiator installation during the thermal balance test;

[0050] Figure 3 A flowchart illustrating an exemplary embodiment of this disclosure;

[0051] Among them: 1-test container, 2-infrared cage, 3-radiator, 4-fluid circuit hose, 5-liquid nitrogen cold plate, 6-suspension rope, 7-satellite body, 8-test platform, 9-radiator mounting bracket, 10-radiator hoisting screw, 11-M8 pre-embedded screw hole. Detailed Implementation

[0052] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0053] This disclosure provides a method for conducting equivalent thermal balance tests on a satellite with a deployable radiator. The method analyzes the heat transfer relationship between the deployable radiator and the satellite body using whole-satellite thermal analysis, providing a theoretical basis for conducting thermal balance tests by placing the radiator and satellite body in separate zones. It ensures the heat transfer capacity from the satellite body to the deployable radiator by replacing the metal flexible hoses connecting them. The infrared cages of the deployable radiator and the satellite body are separated by a liquid nitrogen cold plate to prevent mutual interference. The method uses the temperature data after thermal balance to correct the heat transfer between the deployable radiator and the satellite body, and then reapplies this heat transfer to the target via external heat flow, achieving iterative correction.

[0054] The process according to exemplary embodiments of this disclosure is as follows: Figure 3 As shown, it includes the following steps:

[0055] 1) Establish a whole-satellite thermal analysis model, and calculate and analyze the radiative heat transfer coefficient between the radiator and the adjacent structural plate through the model, so as to determine the heat transfer between the radiator and the adjacent structural plate.

[0056] 2) Attach thermocouples for measuring temperature and heat flow meters for measuring heat flux to the radiator and adjacent structural plates.

[0057] 3) The satellite body, the satellite body infrared cage, the liquid nitrogen cooling plate, the radiator infrared cage, and the radiator are sequentially installed in the test container. The liquid nitrogen cooling plate separates the satellite body infrared cage and the radiator infrared cage. The radiator has an M8 threaded hole on its side. A long screw is screwed into the screw hole of the radiator through the through hole on the bracket. The other side of the long screw is fixed to the bracket with a nut.

[0058] 4) Connect the radiator and the satellite body to the fluid circuit via a metal hose, and then suspend and fix the metal hose to the top of the test container using a rope.

[0059] 5) In the thermal equilibrium test, an external heat flow is first applied to the radiator and the satellite body according to the initial calculation results. After the test conditions are balanced (temperature stabilized), the temperature data of the radiator and the adjacent satellite structural plate are recorded. The recorded temperature is compared with the temperature data in the analysis model. If the difference is large, the actual temperature data is substituted into formulas (1) and (2) to calculate the heat exchange between the radiator and the satellite body (i.e., radiative heat flow). This heat exchange is then reapplied to the radiator and the adjacent satellite structural plate as an external heat flow to complete the first correction iteration. After the temperature is balanced, the above iteration is repeated until the test requirements are met (the temperature is basically consistent with the model temperature).

[0060] The above technical solutions are merely exemplary embodiments of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the specific embodiments of the present invention. Therefore, the methods described above are merely preferred and not restrictive.

Claims

1. A method for conducting an equivalent thermal balance test on a satellite equipped with a deployable radiator, comprising the following steps: S1. Establish a whole-satellite thermal analysis model to calculate the extra-orbital heat flux and infrared radiation heat flux of various parts of the satellite, including the deployable radiator. S2, The satellite body and the radiator are installed separately in the test container, and infrared heat flow simulation devices are set up for them respectively, and they are separated by liquid nitrogen cold plates; the fluid loop connecting the radiator and the satellite body is connected by a metal hose to simulate a closed fluid loop heat dissipation system. S3. In the thermal balance test, an external heat flow is first applied to the satellite body and radiator according to the initial calculation results. After the test conditions are balanced, the temperature data of the radiator and the adjacent structural plates of the satellite are recorded. The recorded temperature is compared with the temperature data in the whole satellite thermal analysis model. If the difference is large, the heat exchange between the radiator and the adjacent structural plates of the satellite is calculated based on the measured temperature. Based on the calculation results, the external heat flow of the radiator and the satellite body is corrected again. After the temperature is balanced, the above iterative work is repeated until the test requirements are met. In step S1, the infrared radiation heat flux of various parts of the satellite includes: The deployable radiator absorbs infrared radiation heat flux from adjacent structural panels of the satellite. （1） The satellite structural panels absorb the infrared radiation heat flux of the deployable radiator. （2） The solar panel absorbs the infrared radiation heat flux from the deployable radiator. （3） Infrared radiation heat flux from solar panels to satellite structural panels: （4） Where Q1~Q4 represent infrared radiation heat flux in W; m, n, and s represent the number of nodes in the deployable radiator, satellite structure plate, and solar panel model, respectively; i, j, and k are the corresponding node numbers; ε represents the surface infrared emissivity, dimensionless; and A represents the area in m². 2 B i,j B is the radiative heat transfer coefficient of the deployable radiator to the adjacent structural plates of the satellite. j,i B is the radiative heat transfer coefficient of the satellite's adjacent structural plates to the deployable radiator. k,i B is the radiative heat transfer coefficient of the solar panel to the deployable radiator. k,j is the radiative heat transfer coefficient of the solar panels to the adjacent structural panels of the satellite; T is the temperature calculated in the whole satellite thermal analysis model, in K.

2. The method according to claim 1, characterized in that, The external heat flow simulation device in step S2 uses an infrared cage.

3. The method according to claim 1, characterized in that, In step S2, the installation method of the deployable radiator includes: The radiator has aluminum alloy embedded blocks on all four edges of the radiator's radiating plate and is designed with M8 screw holes. The radiator is hoisted onto the trapezoidal test bracket using tooling, and the normal of the radiating plate is perpendicular to the direction of gravity.

4. The method according to claim 1, characterized in that, In step S2, the surface of the metal hose is heated by an electric heating wire, and then covered with a multi-layer heat insulation component.

5. The method according to any one of claims 1-4, characterized in that, It also includes the following steps: Several heat flux meters are attached to the radiator and the satellite body to measure the arriving infrared heat flux; Several thermocouples are attached to the radiator and the satellite body to measure temperature.

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