An external heat flow simulation method for low-orbit satellite batch heat test

Abstract

The application is a method for simulating external heat flow for low-orbit satellite batch thermal test. The application relates to the field of aerospace technology, and utilizes a vacuum test equipment heat sink to complete space external heat flow simulation and "cold, black" environment simulation. The method reduces resource consumption of a single satellite in the test, is suitable for satellite batch development, and is suitable for new satellite research and batch satellite production. The method reduces the use of external heat flow simulation devices, reduces the design and manufacturing period and cost of the infrared heating cage, and improves the safety of the thermal test. In the test process, nitrogen is used to control the heat sink temperature, which is energy-saving, environmentally friendly, economical, and the heat sink has a fast temperature rising and falling speed, which can significantly shorten the thermal equilibrium and the test time in the thermal vacuum. The test method has strong transplantability and can be applied to external heat flow simulation of common low-orbit satellites such as sun-synchronous orbit and low-inclination orbit.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology and is a method for simulating external heat flow in batch thermal tests of low-orbit satellites. Background Technology

[0002] Vacuum thermal testing of spacecraft is one of the most complex, costly, and time-consuming tests in the spacecraft development process. It is an effective and necessary means to improve the on-orbit reliability of spacecraft. External heat flow is the main simulation element of thermal tests, and the accuracy of the external heat flow simulation directly affects the success or failure of the test.

[0003] In the 1980s, Academician Min Guirong proposed developing infrared heating simulation as a primary means of spacecraft testing. To this day, infrared heating cages remain the most common method for simulating extraterrestrial heat flow. With the rise of commercial spaceflight, low-Earth orbit (LEO) satellites are becoming more sensitive to development costs and timelines, and the contradiction between speed and reliability in the development process is becoming more prominent. How to conduct reliable and efficient thermal testing has become an urgent problem to be solved. Exploring a set of efficient and reliable whole-satellite thermal testing methods based on traditional thermal testing is of great significance for LEO satellites that pursue low cost and short development cycles.

[0004] To address this issue, a method for simulating external heat flow in batch thermal tests of satellites is proposed. This method innovatively employs a vacuum testing facility with a heat sink to simulate external heat flow in space and a "cold, dark" environment. While ensuring satellite reliability, it aims to reduce development costs and shorten the vacuum thermal testing cycle. This external heat flow simulation method saves on the manufacturing costs of infrared heating cages (radiation plates), improves testing efficiency, saves testing time, and ensures the safety and reliability of the tests. Furthermore, this method reduces the resource consumption (space resources, energy resources, etc.) of a single satellite during testing, making it suitable for the batch development of low-Earth orbit satellites.

[0005] Patent Title: An External Heat Flow Simulation Device for Microsatellites, Patent No.: 202020338461.0 describes an external heat flow simulation device for microsatellites, including a support frame and a heating assembly. Essentially, it is still an infrared radiation plate external heat flow simulation device, with its heating assembly fixed within the support frame. The heating assembly includes a heating substrate, a heat-conducting plate on one side of the heating substrate, and multiple heaters on the other side of the heating substrate. The heat-conducting plate side faces the experimental microsatellite. This invention's uniformly heated plate-shaped heating assembly enhances the uniformity of heat flow, has a simple structure, is easy to manufacture, and has a low overall cost, making it suitable for simulating external heat flow in satellite thermal experiments. However, this invention has the following shortcomings:

[0006] 1. Infrared radiation plates, as external heat flow simulation devices, require vacuum container heat sink temperatures as low as possible. Using liquid nitrogen to cool the heat sink to below 100K involves slow heating and cooling rates, long experimental cycles, and high costs.

[0007] 2. The support frame and heating components have poor versatility and can generally only be adapted to one type of satellite;

[0008] 3. If the satellite has a complex shape, the error in simulating external heat flow will increase significantly, and the design and partitioning of the heating components will become more complex, resulting in reduced safety of the experiment;

[0009] 4. Each satellite participating in the test needs to be equipped with a separate heating component, resulting in a low cost-effectiveness ratio and making it unsuitable for conducting batch thermal tests on satellites. Summary of the Invention

[0010] This invention is primarily intended for application in low-Earth orbit (LEO) satellite thermal testing technology. Its aim is to improve the efficiency of spacecraft thermal testing, reduce testing costs, and make it suitable for batch testing of satellites. Based on this, this invention provides an external heat flow simulation method for batch thermal testing of LEO satellites.

[0011] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0012] This invention provides a method for simulating external heat flow in batch thermal tests of low-Earth orbit satellites. The invention provides the following technical solution:

[0013] A method for simulating external heat flow in batch thermal tests of low-Earth orbit satellites, the method comprising the following steps:

[0014] Step 1: Analyze the external heat flow of the satellite in various directions, and use the obtained external heat flow results of the satellite orbit as input conditions;

[0015] Step 2: Divide the satellite surface into multiple external heat flow simulation regions to determine the regions where heat sink simulation can be used;

[0016] Step 3: Determine whether the external heat flow is completely simulated by the heat sink;

[0017] Step 4: If there are still areas on the satellite surface that require the installation of external heat flow simulation devices, calculate the control point temperature of the external heat flow simulation device area;

[0018] Step 5: When the external heat flow of the satellite can be simulated using the heat sink equivalent, normalize the external heat flow in the heat sink simulation region;

[0019] Step 6: After completing the heat flux normalization process, calculate the heat sink set temperature in the simulated external heat flux region;

[0020] Step 7: After determining the heat sink set temperature, perform experimental model simulation verification. When it is necessary to re-divide the area of ​​the heat sink equivalent simulation external heat flow, that is, repeat step 2.

[0021] Preferably, step 2 specifically comprises:

[0022] The satellite surface is divided into n simulated external heat flow regions. When the K of region i is... i If the number is less than n, the area is considered suitable for simulating external heat flow using a heat sink; otherwise, an additional heat flow simulation device is required for the area. i The number is calculated using the following formula:

[0023]

[0024] Among them, Q i Q j The orbital arrival heat flux densities C in regions i and j are respectively. i For the equivalent specific heat capacity of the satellite in this region, A i M represents the equivalent area corresponding to the satellites in this region. i ΔT represents the equivalent mass of the satellite in this region, and ΔT is the allowable error.

[0025] Preferably, step 4 specifically comprises:

[0026] The external heat flow simulation device uses a radiant plate for closed-loop temperature control in area j, and the control point temperature is expressed by the following formula:

[0027]

[0028] Among them, Q Solar-j Q is the solar radiation heat flux density reaching region j. albedo-j Q is the Earth's albedo heat flux density reaching region j. EarthIR-j σ is the infrared heat flux density of the Earth reaching region j, σ is the Stefan Boltzmann constant, and α is the infrared radiation heat flux density reaching region j. j Let ε be the solar absorptivity of the satellite surface in region j. j Infrared absorption emissivity of satellite surface in region j.

[0029] Preferably, step 5 specifically comprises:

[0030] The heat flow in the simulated external heat flow region i using the heat sink is normalized using formula (3):

[0031]

[0032] Where, q avgThe normalized satellite absorbed heat flux density is used to calculate the heat sink setup temperature during thermal experiments, Q. Solar-i Q is the solar radiation heat flux density reaching region i. albedo-i Q is the Earth's albedo heat flux density reaching region i. EarthIR-i α is the Earth's infrared radiation heat flux density reaching region i. i Let ε be the solar absorptivity of the satellite surface in region i. i The infrared absorptivity of the satellite surface in region i, A S This represents the surface area of ​​the satellite.

[0033] Preferably, step 6 specifically comprises:

[0034] The temperature required to be set when simulating external heat flow in the heat sink of a vacuum testing equipment is calculated using the following formula:

[0035]

[0036] Where T0 is the heat sink temperature of the vacuum container, ε s The equivalent emissivity of the satellite surface.

[0037] Preferably, step 7 specifically comprises:

[0038] Using δ avg It can measure the magnitude of error in a thermal test model;

[0039]

[0040]

[0041] Where, δ avg δ represents the average error of the thermal test. i This is the predicted error of a single component's thermal test, where η represents the number of components, and T... i 'T' represents the predicted average temperature for the thermal test of the i-th component. i The on-orbit predicted average temperature for the i-th component.

[0042] Preferably, the allowable error ΔT is determined based on the specific circumstances of the heat extraction test, and should satisfy ΔT≥ΔT2.

[0043] An external heat flow simulation system for batch thermal testing of low-Earth orbit satellites, the system comprising:

[0044] The data analysis module analyzes the external heat flow of the satellite in various directions and uses the obtained external heat flow results of the satellite orbit as input conditions.

[0045] The partitioning module divides the satellite surface into multiple external heat flow simulation regions and determines the regions that can be simulated using heat sinks.

[0046] The judgment module determines whether the external heat flow is completely simulated by the heat sink;

[0047] The control point temperature determination module calculates the control point temperature of the area where the external heat flow simulation device needs to be installed when there are still areas on the satellite surface where the external heat flow simulation device needs to be installed.

[0048] The normalization module performs heat flow normalization processing on the external heat flow of the satellite in the heat sink simulation region, where the external heat flow can be simulated using the heat sink equivalent.

[0049] The temperature calculation module performs the normalization of heat flow and then calculates the set temperature of the heat sink in the simulated external heat flow area.

[0050] The verification module performs experimental model simulation verification after determining the heat sink set temperature, and re-divides the area that needs to simulate the external heat flow of the heat sink.

[0051] A computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement an external heat flow simulation method for batch thermal testing of low-Earth orbit satellites.

[0052] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement an external heat flow simulation method for batch thermal testing of low-Earth orbit satellites.

[0053] The present invention has the following beneficial effects:

[0054] Compared with the prior art, the present invention:

[0055] To address the problems existing in the prior art, this invention proposes an external heat flow simulation method for batch thermal testing of satellites. This method directly utilizes a vacuum testing equipment heat sink to simulate external heat flow in space and the "cold, dark" environment. This method reduces the resource consumption (space resources, energy resources, etc.) of a single satellite during testing, making it suitable for batch satellite development and applicable to both newly developed and mass-produced satellites. Reducing the use of external heat flow simulation devices lowers the design and manufacturing cycle and cost of infrared heating cages, and also improves the safety of thermal testing. The use of gaseous nitrogen to control the heat sink temperature during testing is energy-saving, environmentally friendly, and economical. The rapid heating and cooling of the heat sink significantly shortens the testing time for thermal equilibrium and thermal vacuum. The testing method is highly portable and applicable to the external heat flow simulation of common low-Earth orbit satellites such as those in sun-synchronous orbits and low-inclination orbits. Attached Figure Description

[0056] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0057] Figure 1 Implementation process of an external heat flow simulation method for batch thermal testing of satellites;

[0058] Figure 2 A schematic diagram of the satellite and the vacuum container when using a vacuum container heat sink to simulate external heat flow;

[0059] Figure 3 A schematic diagram defining the satellite coordinate system;

[0060] Figure 4 For comparison of testing time and liquid nitrogen consumption for different experimental methods;

[0061] Figure 5 This is a comparison between the heat sink equivalent thermal balance test results and the on-orbit temperature. Detailed Implementation

[0062] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0064] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0065] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0066] The present invention will be described in detail below with reference to specific embodiments. Specific Implementation Example 1:

[0068] according to Figures 1-5 As shown, the specific optimized technical solution adopted by the present invention to solve the above-mentioned technical problems is: The present invention relates to an external heat flow simulation method for batch thermal tests of low-orbit satellites.

[0069] A method for simulating external heat flow in batch thermal tests of low-Earth orbit satellites, the method comprising the following steps:

[0070] Step 1: Analyze the external heat flow of the satellite in various directions, and use the obtained external heat flow results of the satellite orbit as input conditions;

[0071] Step 2: Divide the satellite surface into multiple external heat flow simulation regions to determine the regions where heat sink simulation can be used;

[0072] Step 2 specifically involves:

[0073] The satellite surface is divided into n simulated external heat flow regions. When the K of region i is... i If the number is less than n, the area is considered suitable for simulating external heat flow using a heat sink; otherwise, an additional heat flow simulation device is required for the area. i The number is calculated using the following formula:

[0074]

[0075] Among them, Q i Q j The orbital arrival heat flux densities C in regions i and j are respectively. i For the equivalent specific heat capacity of the satellite in this region, A i M represents the equivalent area corresponding to the satellites in this region. i ΔT represents the equivalent mass of the satellite in this region, and ΔT is the allowable error.

[0076] Step 3: Determine whether the external heat flow is completely simulated by the heat sink;

[0077] Step 4: If there are still areas on the satellite surface that require the installation of external heat flow simulation devices, calculate the control point temperature of the external heat flow simulation device area;

[0078] Step 4 specifically involves:

[0079] The external heat flow simulation device uses a radiant plate for closed-loop temperature control in area j, and the control point temperature is expressed by the following formula:

[0080]

[0081] Among them, Q Solar-j Q is the solar radiation heat flux density reaching region j. albedo-j Q is the Earth's albedo heat flux density reaching region j. EarthIR-j σ is the infrared heat flux density of the Earth reaching region j, σ is the Stefan Boltzmann constant, and α is the infrared radiation heat flux density reaching region j. j Let ε be the solar absorptivity of the satellite surface in region j. j Infrared absorption emissivity of satellite surface in region j.

[0082] Step 5: When the external heat flow of the satellite can be simulated using the heat sink equivalent, normalize the external heat flow in the heat sink simulation region;

[0083] Step 5 specifically involves:

[0084] The heat flow in the simulated external heat flow region i using the heat sink is normalized using formula (3):

[0085]

[0086] Where, q avg The normalized satellite absorbed heat flux density is used to calculate the heat sink setup temperature during thermal experiments, Q. Solar-i Q is the solar radiation heat flux density reaching region i. albedo-i Q is the Earth's albedo heat flux density reaching region i. EarthIR-i α is the Earth's infrared radiation heat flux density reaching region i. i Let ε be the solar absorptivity of the satellite surface in region i. i The infrared absorptivity of the satellite surface in region i, A S This represents the surface area of ​​the satellite.

[0087] Step 6: After completing the heat flux normalization process, calculate the heat sink set temperature in the simulated external heat flux region;

[0088] Step 6 specifically involves:

[0089] The temperature required to be set when simulating external heat flow in the heat sink of a vacuum testing equipment is calculated using the following formula:

[0090]

[0091] Where T0 is the heat sink temperature of the vacuum container, ε s The equivalent emissivity of the satellite surface.

[0092] Step 7: After determining the heat sink set temperature, perform experimental model simulation verification. When it is necessary to re-divide the area of ​​the heat sink equivalent simulation external heat flow, that is, repeat step 2.

[0093] Step 7 specifically involves:

[0094] Using δ avg It can measure the magnitude of error in a thermal test model;

[0095]

[0096]

[0097] Where, δ avg δ represents the average error of the thermal test. i This is the predicted error of a single component's thermal test, where η represents the number of components, and T... i 'T' represents the predicted average temperature for the thermal test of the i-th component. i The on-orbit predicted average temperature for the i-th component.

[0098] The allowable error ΔT is determined based on the specific circumstances of the heat extraction test, and should satisfy ΔT≥ΔT2.

[0099] This invention provides an external heat flow simulation system for batch thermal testing of low-Earth orbit satellites, the system comprising:

[0100] The data analysis module analyzes the external heat flow of the satellite in various directions and uses the obtained external heat flow results of the satellite orbit as input conditions.

[0101] The partitioning module divides the satellite surface into multiple external heat flow simulation regions and determines the regions that can be simulated using heat sinks.

[0102] The judgment module determines whether the external heat flow is completely simulated by the heat sink;

[0103] The control point temperature determination module calculates the control point temperature of the area where the external heat flow simulation device needs to be installed when there are still areas on the satellite surface where the external heat flow simulation device needs to be installed.

[0104] The normalization module performs heat flow normalization processing on the external heat flow of the satellite in the heat sink simulation region, where the external heat flow can be simulated using the heat sink equivalent.

[0105] The temperature calculation module performs the normalization of heat flow and then calculates the set temperature of the heat sink in the simulated external heat flow area.

[0106] The verification module performs experimental model simulation verification after determining the heat sink set temperature, and re-divides the area that needs to simulate the external heat flow of the heat sink.

[0107] The present invention provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement an external heat flow simulation method for batch thermal testing of low-Earth orbit satellites.

[0108] The present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement an external heat flow simulation method for batch thermal testing of low-orbit satellites. Specific Implementation Example 2:

[0110] The only difference between Embodiment 2 and Embodiment 1 of this application is that:

[0111] To achieve the above objectives, the present invention provides the following technical solution:

[0112] A method for simulating external heat flow in batch thermal tests of satellites includes steps such as analyzing external heat flow in satellite orbit and calculating the heat sink setting temperature to simulate external heat flow during thermal tests. The specific implementation process is as follows: Figure 1 As shown.

[0113] The thermal environment of the space where the satellite is located mainly includes three aspects: "cold", "dark", and external heat flow.

[0114] In the thermal test, the "coldness" and "darkness" of the real space environment, as well as the heat flow outside the orbit, can all be simulated by the heat sink of the vacuum test equipment.

[0115] First, based on the mission input, orbit type and satellite external heat flux analysis are performed to determine the regions where heat sink equivalence simulation of external heat flux can be used. For regions where heat sink equivalence simulation is not feasible, fixed devices are installed to simulate external heat flux. Then, heat flux normalization is performed on the remaining regions to obtain the average satellite absorbed heat flux for that region. Using the absorbed heat flux, the temperature value that the heat sink should be set at in the experiment can be calculated, achieving the triple objective of heat sink simulation of "cold, black" conditions and external heat flux. Finally, a simulation model is established to predict the satellite test results, which are compared with the satellite's on-orbit predicted data. If the error is less than the allowable error ΔT, the external heat flux simulation scheme is considered accurate and effective; otherwise, the regions for heat sink equivalence simulation of external heat flux need to be redefined.

[0116] In implementation step S1, the external heat flow of the satellite in various directions is analyzed, mainly including three parts: solar incident heat flow, Earth albedo heat flow, and Earth infrared heat flow. Heat flow analysis is generally performed using specialized engineering software. The obtained results of the satellite orbital external heat flow analysis are used as input conditions for the next step of the analysis.

[0117] In implementation step S2, the satellite surface is divided into n external heat flow simulation regions, when region i's K i If the number is less than n, the area is considered suitable for simulating external heat flow using a heat sink; otherwise, an additional heat flow simulation device is required for the area. i The calculation method for the number is shown in equation (1);

[0118]

[0119] Among them, Q i Q j The orbital arrival heat flux densities C in regions i and j are respectively. i For the equivalent specific heat capacity of the satellite in this region, A i M represents the equivalent area corresponding to the satellites in this region. i ΔT represents the equivalent mass of the satellite in this region, and ΔT represents the allowable error for this experiment.

[0120] After completing the S2 calculation step, proceed to the judgment step S3: If the external heat flow of the satellite can be simulated by heat sink equivalent, then skip directly to step S5 to perform the normalization of the external heat flow; if there are still areas on the satellite surface that require the installation of external heat flow simulation devices, then proceed to step S4 to calculate the control point temperature of the external heat flow simulation device area.

[0121] In implementation step S4, the external heat flow simulation device region j uses a radiant plate for closed-loop temperature control during the thermal test. The formula for calculating the control point temperature is:

[0122]

[0123] Among them, Q Solar-j Q is the solar radiation heat flux density reaching region j. albedo-j Q is the Earth's albedo heat flux density reaching region j. EarthIR-j σ is the infrared heat flux density of the Earth reaching region j, σ is the Stefan Boltzmann constant, and α is the infrared radiation heat flux density reaching region j. j Let ε be the solar absorptivity of the satellite surface in region j. j Infrared absorption (emission) rate of satellite surface in region j.

[0124] Step S4 completes the heat flow simulation control settings for region j of the external heat flow simulation device.

[0125] After setting the control point temperature of the external heat flow simulation device area, proceed to step S5. The heat flow of the external heat flow region i simulated by the heat sink is normalized using formula (3):

[0126]

[0127] Where, q avg The normalized satellite absorbed heat flux density is used to calculate the heat sink setup temperature during thermal experiments, Q. Solar-i Q is the solar radiation heat flux density reaching region i. albedo-i Q is the Earth's albedo heat flux density reaching region i. EarthIR-i α is the Earth's infrared radiation heat flux density reaching region i. i Let ε be the solar absorptivity of the satellite surface in region i. i The infrared absorption (emissivity) of the satellite surface in region i, A S This represents the surface area of ​​the satellite.

[0128] After completing the heat flux normalization process, the heat sink setting temperature in the simulated external heat flux region is calculated, i.e., step S6.

[0129] In implementation step S6, the temperature calculation formula that needs to be set when simulating external heat flow in the heat sink of the vacuum testing equipment is:

[0130]

[0131] Where T0 is the heat sink temperature of the vacuum container, ε s The equivalent emissivity of the satellite surface.

[0132] The derivation of formula (4) is as follows:

[0133] The cosmic background temperature is approximately 3K. Ignoring cosmic background radiation, the heat balance equation for the satellite in orbit is:

[0134] q solar +q albedo +q EarthIR +q n =q o (5)

[0135] Where, q Solar It is the heat absorbed by the satellite from solar radiation, q albedo It is the heat absorbed by the satellite from Earth's reflected sunlight, q EarthIR It is the heat absorbed by the satellite from Earth's infrared radiation, q n It is an internal heat source, q o It is the heat radiated outward by the satellite.

[0136] Assuming the satellite has a fully convex surface, the average heat flux absorbed in orbit is q. avg (i.e., q)Solar q albedo q EarthIR (The average). After the satellite reaches thermal equilibrium, the on-orbit equilibrium equation can be written as:

[0137]

[0138] Among them, T a This refers to the surface temperature of the satellite in orbit.

[0139] In the satellite thermal test, ignoring the obstruction of heat transfer between the satellite and the heat sink by the test fixture, the heat balance equation of the test is:

[0140]

[0141] Among them, T S Let ε0 be the surface temperature of the satellite under test conditions, ε0 be the emissivity of the vacuum container surface, and A0 be the surface area of ​​the heat sink. According to formulas (6) and (7), we can obtain:

[0142]

[0143] The surface temperature of the experimental and in-orbit satellites is essentially the same, i.e., T. a ≈T S When the difference between the satellite's surface area and the heat sink's surface area is sufficiently large, and the heat sink's emissivity is sufficiently high, it can be considered that... Then, the temperature that the heat sink should be set in the heat sink equivalent heat balance test method can be obtained from equation (8):

[0144]

[0145] Due to approximation The resulting error can be expressed as:

[0146]

[0147] in,

[0148] From formula (9), when A S When / A0<0.1 and ε0>0.9, the principle error of the heat sink equivalent test method model is less than 1℃.

[0149] Formula (4) has been derived.

[0150] Finally, the calculated external heat flow simulation method and control temperature are verified through simulation.

[0151] In the implementation step S7, after determining the heat sink set temperature in the test, the test model simulation verification needs to be performed. If the test model verification result is compared with the on-orbit prediction result and the allowable error ΔT is met, the external heat flow simulation method of the test can be considered reasonable. Otherwise, the area of ​​the heat sink equivalent simulation external heat flow needs to be re-divided, that is, step S2 needs to be executed again.

[0152] Using δ avg It can be used to measure the magnitude of error in a thermal test model.

[0153]

[0154]

[0155] Where, δ avg δ represents the average error of the thermal test. i This is the predicted error of a single component's thermal test, where η represents the number of components, and T... i 'T' represents the predicted average temperature for the thermal test of the i-th component. i The on-orbit predicted average temperature for the i-th component.

[0156] Generally, the allowable error ΔT is determined based on the specific circumstances of the heat extraction test, and should satisfy ΔT≥ΔT2.

[0157] This invention utilizes a vacuum test equipment heat sink to perform three tasks: space external heat flow simulation and "cold and black" simulation. While ensuring satellite reliability, it aims to reduce development costs and shorten the vacuum thermal test cycle. This external heat flow simulation method saves on the manufacturing cost of infrared heating cages (radiation plates), improves test efficiency, saves test time, and ensures the safety and reliability of the test. Furthermore, this method reduces the resource consumption (space resources, energy resources, etc.) of a single satellite during the test, making it suitable for mass production of satellites.

[0158] Each satellite can save tens to hundreds of thousands of yuan in design and manufacturing costs for infrared heating cages (radiation plates). Compared with traditional thermal tests for satellites, the test cycle is shortened by one-third, the hourly liquid nitrogen consumption is reduced by more than half, and a single test can save more than 70% of energy consumption (economic expenditure).

[0159] Figure 2 The diagram shows the satellite and vacuum container when using a vacuum container heat sink to simulate external heat flow. It can be seen that there are no external heat flow simulation devices such as infrared heating cages (radiation plates) between the satellite and the vacuum container heat sink.

[0160] An optical remote sensing satellite is designed with a 535km SSO orbit, with its descending node at 11:00 AM local time. The satellite has a mass of approximately 230kg and an envelope size of 785×1140×1800mm. Its fixed coordinates are as follows: Figure 3 As shown, the description is as follows.

[0161] • Origin O: Center of the docking plane circle between the satellite docking ring and the rocket adapter;

[0162] • OZ: Parallel to the optical axis, pointing towards the optical camera;

[0163] • OX: Within the satellite docking surface, in the same direction as the satellite's flight direction;

[0164] • OY: Determined according to the right-hand rule.

[0165] First, an on-orbit heat flux analysis was performed on the satellite. Based on the satellite configuration, size, flight orbit parameters, and flight attitude, the orbital average heat flux density of the incoming external heat flux (solar radiation, Earth albedo, and Earth infrared radiation) on each surface of the satellite was calculated, as shown in Table 1 below.

[0166] Table 1. Average external heat flux density (W / m²) reaching the outer surface of each region when the satellite is oriented towards the sun. 2 )

[0167]

[0168] Based on the analysis results of external heat flow in each region, the formula (1) is used for discrimination. According to the calculation, except for the satellite base plate (-Z) region, other regions can be simulated by using heat sink equivalent to simulate external heat flow. The satellite base plate (-Z) uses an infrared radiation plate in conjunction with a heat flow meter to achieve closed-loop control of heat flow to simulate the external heat flow in this region.

[0169] First, use formula (2) to calculate the temperature setting value of the closed-loop control point of the satellite-Z-plane radiant heat flow meter. Based on the average heat flow of the -Z-plane on the winter solstice (perihelion) and summer solstice (aphelion) in the table, calculate the corresponding temperature setting values ​​of the control point for the high temperature and low temperature conditions of the test, which are 37.3℃ and -19.6℃, respectively.

[0170] Then, based on the satellite's surface optical properties and formula (3), the heat flux in regions other than the -Z plane is normalized, and the average heat flux absorbed by the satellite on the winter solstice (perihelion) can be calculated as q. avg =84W / m 2 The average heat flux absorbed on the summer solstice (aphelion) is q. avg =58W / m 2 According to formula (4), the temperature to be set for simulating external heat flow using a heat sink in the high-temperature test of the satellite is -50℃; and the temperature to be set for the heat sink in the low-temperature test is -70℃. Compared with the -170℃ heat sink temperature of the traditional heat flow simulation method, the heat sink temperature set by the present invention in the test is higher, and gaseous nitrogen can be used for temperature control, which has the advantages of low energy consumption and fast temperature adjustment speed.

[0171] In summary, the external heat flow simulation method in the experiment is as follows: the heat flow in the satellite-Z region is simulated using an infrared radiation plate, and the external heat flow in other regions of the satellite is simulated using heat sinks. Based on this, an experimental simulation model is established and verified against the on-orbit simulation model. After the verification is passed, the formal experiment is carried out.

[0172] Compared to traditional thermal tests, thermal tests utilizing heat sinks to simulate external space heat flow not only ensure the reliability of satellite development but also significantly reduce the test cycle and equipment costs. According to statistics from the satellite's thermal tests, traditional thermal tests take approximately 300 hours, consuming about 0.7 cubic meters of liquid nitrogen per hour. 3 The heat sink equivalent heat test takes approximately 200 hours, consuming about 0.3 m³ of liquid nitrogen per hour. 3 The test cycle was shortened by one-third, and the hourly liquid nitrogen consumption was reduced by more than half. Specific data is summarized as follows: Figure 4 As shown.

[0173] In this application example, the vacuum container heat sink is a cylindrical structure with a diameter of 6m and a length of 12m. Therefore, the ratio of the heat sink surface area to the satellite surface area is greater than 10, and the heat sink surface emissivity is greater than 0.9. According to formula (9), the error of the thermal test result should be within 1℃.

[0174] Comparative analysis of the satellite's thermal test results and on-orbit flight data, such as Figure 5 As shown:

[0175] Based on the on-orbit flight data, analysis was performed using formulas (10) and (11). The error of the thermal test for this satellite was 0.9℃. This indicates that the error of the external heat flow simulation method is consistent with expectations. This method can achieve good accuracy in thermal tests and can meet the requirements of various items in the thermal test.

[0176] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or N embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of the present invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified. Any process or method described in the flowcharts or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logical functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order according to the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain. The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection having one or N wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic device, and portable optical disc read-only memory (CDROM).Furthermore, the computer-readable medium can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory. It should be understood that various parts of the invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0177] The above description is merely a preferred embodiment of an external heat flow simulation method for batch thermal testing of low-Earth orbit satellites. The scope of protection for such a method is not limited to the above embodiments; all technical solutions falling within this conceptual framework are within the scope of protection of this invention. It should be noted that for those skilled in the art, any improvements and variations made without departing from the principles of this invention should also be considered within the scope of protection of this invention.

Claims

1. A method for simulating external heat flow in batch thermal tests of low-Earth orbit satellites, characterized by: The method includes the following steps: Step 1: Analyze the external heat flow of the satellite in various directions, and use the obtained external heat flow results of the satellite orbit as input conditions; Step 2: Divide the satellite surface into multiple external heat flow simulation regions to determine the regions where heat sink simulation can be used; Step 3: Determine whether the external heat flow is completely simulated by the heat sink; Step 4: If there are still areas on the satellite surface that require the installation of external heat flow simulation devices, calculate the control point temperature of the external heat flow simulation device area; Step 4 specifically involves: The external heat flow simulation device uses a radiant plate for closed-loop temperature control in area j, and the control point temperature is expressed by the following formula: ，(2) in, Q Solar-j It is the arrival area j The solar radiation heat flux density, Q albedo-j It is the arrival area j Earth's reflective heat flux density, Q EarthIR-j It is the arrival area j Earth's infrared radiation heat flux density, σ This is the Stefan Boltzmann constant. α j For the region j The solar absorptivity of the satellite surface ε j area j The infrared absorption emissivity of the satellite surface; Step 5: When the external heat flow of the satellite can be simulated using the heat sink equivalent, normalize the external heat flow in the heat sink simulation region; Step 6: After completing the heat flux normalization process, calculate the heat sink set temperature in the simulated external heat flux region; Step 7: After determining the heat sink set temperature, perform experimental model simulation verification. When it is necessary to re-divide the area of ​​the heat sink equivalent simulation external heat flow, that is, repeat step 2.

2. The method according to claim 1, characterized in that: Step 5 specifically involves: The heat sink will be used to simulate the external heat flow region. i The heat flux is normalized using formula (3): ，(3) in, q avg The normalized satellite absorbed heat flux density is used to calculate the heat sink setup temperature during thermal experiments. Q Solar-i It is the arrival area i The solar radiation heat flux density, Q albedo-i It is the arrival area i Earth's reflective heat flux density, Q EarthIR-i It is the arrival area i Earth's infrared radiation heat flux density, α i For the region i The solar absorptivity of the satellite surface ε i area i The infrared absorption emissivity of the satellite surface, A S This represents the surface area of ​​the satellite.

3. The method according to claim 2, characterized in that: Step 6 specifically involves: The temperature required to be set when simulating external heat flow in the heat sink of a vacuum testing equipment is calculated using the following formula: ，(4) in, T 0 represents the heat sink temperature of the vacuum container. ε s The equivalent emissivity of the satellite surface.

4. The method according to claim 3, characterized in that: Step 7 specifically involves: use It can measure the magnitude of error in a thermal test model; ，(10) ，(11) in, Represents the average error of the thermal test. This is an error predicted by the thermal test of a single component. η Represents the number of components. For the first i The thermal test results for each component indicate the average temperature. For the first i The on-orbit average temperature of each component is predicted.

5. An external heat flow simulation system for batch thermal testing of low-Earth orbit satellites, said system operating based on the external heat flow simulation method for batch thermal testing of low-Earth orbit satellites according to claim 1, characterized in that: The system includes: The data analysis module analyzes the external heat flow of the satellite in various directions and uses the obtained external heat flow results of the satellite orbit as input conditions. The partitioning module divides the satellite surface into multiple external heat flow simulation regions and determines the regions that can be simulated using heat sinks. The judgment module determines whether the external heat flow is completely simulated by the heat sink; The control point temperature determination module calculates the control point temperature of the area where the external heat flow simulation device needs to be installed when there are still areas on the satellite surface where the external heat flow simulation device needs to be installed. The normalization module performs heat flow normalization processing on the external heat flow of the satellite in the heat sink simulation region, where the external heat flow can be simulated using the heat sink equivalent. The temperature calculation module performs the normalization of heat flow and then calculates the set temperature of the heat sink in the simulated external heat flow area. The verification module performs experimental model simulation verification after determining the heat sink set temperature, and re-divides the area that needs to simulate the external heat flow of the heat sink.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method as claimed in any one of claims 1-4.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the method of any one of claims 1-4.

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