Spacecraft temperature control partition multi-level simulation method and device

Abstract

The application discloses a spacecraft temperature control partition multi-stage simulation method and device, and the method comprises the following steps: based on a thermal analysis model and a total number of nodes, an energy balance model of a node thermal network is established; the nodes are divided into multi-stage partitions, each partition corresponds to a level and comprises a plurality of nodes; a temperature convergence criterion is set for each partition respectively, and based on the temperature convergence criterion corresponding to each partition, each partition is iteratively simulated in sequence to obtain the temperature corresponding to each node; a unified transient solution end time is set for all the partitions, and a time step is set for each partition respectively; based on the temperature convergence criterion corresponding to each partition and the current solution time, transient heat iteration simulation is performed on each partition in sequence to obtain the temperature corresponding to each node at the current solution time. The method can be applied to similar devices with different temperature requirements and high-precision temperature control, and the solution speed is accelerated.

Description

Technical Field

[0001] This invention relates to the field of simulation technology, specifically to a multi-level simulation method and apparatus for spacecraft temperature control zones. Background Technology

[0002] Spacecraft operate in space, and since most of the equipment on the spacecraft generates heat, it is also affected by the external thermal environment in space. In order to ensure the temperature requirements of various parts of the spacecraft, a reasonable thermal control design is required to collect, transfer and dissipate the heat through various heat transfer methods.

[0003] Existing technologies for analyzing the heat transfer process in spacecraft typically involve constructing a thermal analysis model that characterizes the physical processes of heat transfer in each part, obtaining the heat of various heat transfers through direct input or indirect solution, and finally solving the thermal network equations of the corresponding nodes in each part to obtain the temperature results.

[0004] The basic modes of heat transfer include conduction, convection, and radiation. Conduction and convection are linear thermal conductions and include various forms, such as material-based thermal conductivity, contact heat transfer, convective heat transfer, and (upstream to downstream) fluid transport. Radiative thermal conductance generally requires specialized calculations to determine.

[0005] Thermal network equations typically require iterative methods such as Jacobi and Gauss-Seidel to solve. After each iteration, relaxation methods or similar techniques can be used to further process the temperature results to accelerate convergence. Currently, most research focuses on iterative methods and the processing of temperature results after iteration, while some studies investigate corrections for linear and nonlinear radiative thermal conductance in the equations. However, all known research and methods solve the equations using a unified convergence criterion and time step.

[0006] With the development of thermal design tasks, some equipment has proposed high-precision and high-stability temperature control at the μK level. Therefore, a multi-stage thermal design approach must be adopted, and passive insulation, active temperature control, or both must be implemented at the corresponding levels to achieve the temperature control objectives at each level. However, in the above design process, the thermal design states, such as the passive insulation state and the active temperature control parameters, need to be determined through multiple rapid iterations. Due to the high temperature accuracy requirements, the convergence criterion must be set to at least 10. -1 The minimum heating time for temperature control equipment needs to be set to the order of 0.01 seconds, which is at least 3 to 5 orders of magnitude stricter than conventional thermal analysis. According to traditional methods, all nodes can only be solved using the same criteria and time step, which results in excessive actual solution time and seriously affects the time required to determine the thermal design state through thermal analysis.

[0007] From a practical physical perspective, not all nodes, and even only a few nodes, require control at the μK level. Therefore, this method proposes an accelerated solution for the multi-level thermal network equations of spacecraft temperature control zones, based on the actual physical conditions. This method improves the solution speed and is suitable for solving thermal network equations in the field of high-precision temperature control. It can also be used for solving similar thermal network equations with different temperature requirements, better supporting the iteration of thermal design states and the optimization of thermal design parameters. This method has significant practical engineering application value. Summary of the Invention

[0008] In view of this, the present invention provides a multi-level simulation method and apparatus for spacecraft temperature control zones. The present invention is a high-precision multi-level simulation method and apparatus for spacecraft temperature control zones, which can solve the technical problem of insufficient solution speed of existing methods.

[0009] To solve the above-mentioned technical problems, the present invention is implemented as follows.

[0010] A multi-level simulation method for temperature control zones in spacecraft, the method comprising the following steps:

[0011] Step S1: Establish a thermal analysis model for the spacecraft; determine the nodes of the thermal analysis model, where each node represents the temperature of a different part of the spacecraft; based on the thermal analysis model and the total number of nodes, establish an energy balance model for the node thermal network.

[0012] Step S2: Based on the energy balance model and the allowable temperature range of each node, the nodes are divided into multi-level partitions, each partition corresponding to a level and including several nodes;

[0013] Step S3: Set a temperature convergence criterion for each partition. The temperature convergence criterion is the temperature criterion for all nodes in each partition to reach convergence.

[0014] Step S4: Set a uniform transient solution end time for all partitions, and set a time step for each partition. The time step indicates the time increment for each solution of the partition when the transient iterative calculation is less than the solution end time. Based on the temperature convergence criterion corresponding to each partition and the current solution time, perform transient heat transfer iterative simulation on each partition in sequence to obtain the temperature of each node at the current solution time.

[0015] Preferably, the energy balance model of the nodal thermal network is as follows:

[0016]

[0017] Where i and j represent nodes, N is the total number of nodes, and T i Let m be the temperature of node i. i Let c be the mass of node i.i Let q be the specific heat capacity of node i, t be time, and q be the specific heat capacity of node i. i The heat absorbed by node i includes the heat generated by node i itself, temperature-controlled heating, and heat received from the outside, T j D represents the temperature of node j; ji and G ji Let J represent the linear thermal conductance from node J to node I and the fourth-order nonlinear radiative thermal conductance, respectively. T is the fourth power of the temperature at node i. i 4 Let be the fourth power of the temperature of node j, and let be the relationship between node j and node i, where node i absorbs the heat conducted from node j to node i.

[0018] Preferably, in step S2, the maximum value of the lower limit of the allowable temperature range of each node is taken as the first lower limit, and the minimum value of the upper limit of the allowable temperature range of each node is taken as the first upper limit. The absolute value of the difference between the first upper limit and the first lower limit is taken as the partitioning criterion, denoted as TT. TT is divided into n levels. The node partition with the largest temperature range corresponding to the partitioning criterion is defined as level 1, and the node partition with the smallest temperature range corresponding to the partitioning criterion is defined as level n, 1≤num≤n, where num is the partitioning level. The larger the value of num, the higher the corresponding level.

[0019] Preferably, step S3 involves setting a temperature convergence criterion for each partition, where the temperature convergence criterion is the temperature criterion for all nodes corresponding to each partition to reach convergence; convergence is defined as the absolute value of the temperature difference between the current iteration step and the previous iteration step of a node being less than the temperature convergence criterion; wherein, the higher the level of the partition, the smaller the convergence criterion corresponding to that partition.

[0020] Preferably, step S4 involves: setting a uniform transient solution end time for all partitions, and setting a time step for each partition. The time step indicates the increment in time for each solution operation when the transient iterative calculation for that partition is performed before the solution end time; based on the temperature convergence criterion corresponding to each partition and the current solution time, transient heat transfer iterative simulation is performed sequentially on each partition to obtain the temperature of each node at the current solution time, including:

[0021] Step S41: Set a uniform transient solution end time for all partitions, and set a time step for each partition. The time step indicates the time increment for each solution operation when the transient iteration calculation for that partition is less than the solution end time. The higher the level of the partition, the larger the corresponding time step. num The smaller the value;

[0022] Step S42: Set the current time to time, and assign the initial value of the current time time to step. n step n Let n be the time step for the partition of level n; set a baseline iteration time t0 for each partition. num The initial value is step num step num This represents the time step corresponding to the partition with level num;

[0023] Step S43: If time is greater than the solution completion time, the method ends; otherwise, proceed to step S44.

[0024] Step S44: Determine whether the current time needs to be calculated for each partition in order from level 1 to level n-1; for each partition with level 'level', 1≤level≤n-1, the method for determining whether the current time needs to be calculated is: if the current processing time time≥t0 level Then a solution is needed, specifically based on t0. level Obtain the relevant parameters of the thermal network energy balance model for each node, and perform iterative simulations on all nodes of the partition. When all nodes in the partition satisfy the convergence criterion corresponding to that partition, then all nodes in that partition have reached convergence. Use the temperature corresponding to each node as the temperature result for the current processing time (t0). Finally, set t0... level Assigned the value t0 level +step level If the current processing time is time <t0 level If the partition does not require a solution, the temperature of each node remains constant.

[0025] Step S45: Assign the current processing time (time) to the value of time + step. n step n Let n be the time step corresponding to partition level n; based on the current processing time and the temperature convergence criterion corresponding to partition level n, perform iterative simulation on all nodes of partition level n to obtain the temperature corresponding to each node, and proceed to step S43.

[0026] Preferably, the thermal analysis model is a model that can characterize the heat transfer physical processes of various parts of the spacecraft.

[0027] The present invention provides a multi-level simulation device for spacecraft temperature control zones, the device comprising:

[0028] Modeling module: Configured to build a thermal analysis model for the spacecraft; determine the nodes of the thermal analysis model of the spacecraft, with each node representing the temperature of a different part of the spacecraft; based on the thermal analysis model and the total number of nodes, establish an energy balance model of the node thermal network;

[0029] Partitioning module: configured to divide the nodes into multi-level partitions based on the energy balance model and the allowable temperature range of each node, with each partition corresponding to a level and including several nodes;

[0030] The first simulation module is configured to set a temperature convergence criterion for each partition, wherein the temperature convergence criterion is the temperature criterion for all nodes corresponding to each partition to reach convergence.

[0031] The second simulation module is configured to set a uniform transient solution end time for all partitions and set a time step for each partition. The time step indicates the increment in time for each solution of the partition when the transient iterative calculation is performed before the solution end time. Based on the temperature convergence criterion corresponding to each partition and the current solution time, transient heat transfer iterative simulation is performed on each partition in sequence to obtain the temperature of each node at the current solution time.

[0032] The present invention provides a computer-readable storage medium storing a plurality of instructions; the plurality of instructions are used by a processor to load and execute the method as described above.

[0033] The present invention provides an electronic device, characterized in that the electronic device comprises:

[0034] A processor is used to execute multiple instructions;

[0035] Memory, used to store multiple instructions;

[0036] The plurality of instructions are to be stored in the memory and loaded and executed by the processor as described above.

[0037] The beneficial technical effects of this invention are as follows:

[0038] (1) The present invention constructs a thermal network model for spacecraft, which can accelerate the solution speed of thermal network equations. This method can also be applied to similar equipment that requires high-precision temperature control with different temperature requirements. The present invention can better support the iteration of thermal design state and the optimization of thermal design parameters.

[0039] (2) This invention is based on the idea of ​​multi-level insulation and graded temperature control. It divides the space according to the state of multi-level insulation, sets the convergence criteria according to the temperature control accuracy requirements, and sets the transient time step according to the minimum execution time of the actual temperature control equipment at each level. It can reflect the actual thermophysical process more realistically. Based on this, the proposed partitioned multi-level heat network solution acceleration method can effectively reduce the solution calculation amount except for the last level. The earlier the level, the greater the reduction. Therefore, it can effectively accelerate the heat network solution.

[0040] (3) Compared with the traditional method that can only be processed according to a unified convergence criterion and time step, this invention can effectively reduce the amount of computation, accelerate the solution of thermal network equations, and quickly obtain thermal analysis results.

[0041] (4) This invention can better support the iteration of thermal design state and the optimization of thermal design parameters, and has important practical engineering application significance. Attached Figure Description

[0042] Figure 1 A flowchart of the multi-level simulation method for spacecraft temperature control partitioning provided by the present invention;

[0043] Figure 2 This is a schematic diagram of the multi-level simulation device for spacecraft temperature control zones provided by the present invention. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] like Figure 1 As shown, this invention proposes a multi-level simulation method for spacecraft temperature control zones, the method comprising the following steps:

[0046] Step S1: Establish a thermal analysis model for the spacecraft; determine the nodes of the thermal analysis model, where each node represents the temperature of a different part of the spacecraft; based on the thermal analysis model and the total number of nodes, establish an energy balance model for the node thermal network.

[0047] Step S2: Based on the energy balance model and the allowable temperature range of each node, the nodes are divided into multi-level partitions, each partition corresponding to a level and including several nodes;

[0048] Step S3: Set a temperature convergence criterion for each partition. The temperature convergence criterion is the temperature criterion for all nodes in each partition to reach convergence.

[0049] Step S4: Set a uniform transient solution end time for all partitions, and set a time step for each partition. The time step indicates the time increment for each solution of the partition when the transient iterative calculation is less than the solution end time. Based on the temperature convergence criterion corresponding to each partition and the current solution time, perform transient heat transfer iterative simulation on each partition in sequence to obtain the temperature of each node at the current solution time.

[0050] Furthermore, the thermal analysis model is a model that can characterize the heat transfer physical processes of various parts of the spacecraft.

[0051] Furthermore, the energy balance model of the nodal thermal network is as follows:

[0052]

[0053] Where i and j represent nodes, N is the total number of nodes, and T i Let m be the temperature of node i. i Let c be the mass of node i. i Let q be the specific heat capacity of node i, t be time, and q be the specific heat capacity of node i. i The heat absorbed by node i includes the heat generated by node i itself, temperature-controlled heating, and heat received from the outside, T j D represents the temperature of node j; ji and G ji Let J represent the linear thermal conductance and the fourth-order nonlinear radiative thermal conductance from node J to node i, respectively. T is the fourth power of the temperature at node i. i 4 Let be the fourth power of the temperature of node j, and let be the relationship between node j and node i, where node i absorbs the heat conducted from node j to node i.

[0054] In this equation, the left side represents the rate of change of the internal energy of node i, and the right side represents, in order, the heat absorbed by node i, the total linear thermal conduction heat transfer flowing into node i, and the total radiative heat transfer flowing into node i.

[0055] In step S2, based on the allowable temperature range of each node, the maximum value of the lower limit of the allowable temperature of each node is taken as the first lower limit, and the minimum value of the upper limit of the allowable temperature of each node is taken as the first upper limit. The absolute value of the difference between the first upper limit and the first lower limit is taken as the partitioning criterion, denoted as TT. TT is divided into n levels. The node partition with the largest temperature range corresponding to the partitioning criterion is defined as level 1, and the node partition with the smallest temperature range corresponding to the partitioning criterion is defined as level n, 1≤num≤n, where num is the partitioning level. The larger the value of num, the higher the corresponding level.

[0056] For example, starting from 1K, the division is carried out by decreasing by 1 to 2 orders of magnitude, such as TT≥1K, 10 -2 K≤TT<1K, 10 -4 K≤TT<10 -2 K, 10 -6 K≤TT<10 -4 K serves as the partitioning criterion for levels 1 through 4, respectively.

[0057] Step S3: Set a temperature convergence criterion for each partition. The temperature convergence criterion is the temperature criterion for all nodes corresponding to each partition to reach convergence. Convergence means that the absolute value of the temperature difference between the current iteration step and the previous iteration step of a node is less than the temperature convergence criterion. The higher the level of the partition, the smaller the convergence criterion for that partition.

[0058] Step S4: Set a uniform transient solution end time for all partitions, and set a time step for each partition. The time step indicates the increment in time for each solution operation when the transient iteration calculation for that partition is less than the solution end time. Based on the temperature convergence criterion corresponding to each partition and the current solution time, perform transient heat transfer iterative simulation on each partition sequentially to obtain the temperature of each node at the current solution time, including:

[0059] Step S41: Set a uniform transient solution end time for all partitions, and set a time step for each partition. The time step indicates the time increment for each solution operation when the transient iteration calculation for that partition is less than the solution end time. The higher the level of the partition, the larger the corresponding time step. num The smaller the value;

[0060] Step S42: Set the current time to time, and assign the initial value of the current time time to step. n step n Let n be the time step for the partition of level n; set a baseline iteration time t0 for each partition. num The initial value is step num step num This represents the time step corresponding to the partition with level num;

[0061] Step S43: If time is greater than the solution completion time, the method ends; otherwise, proceed to step S44.

[0062] Step S44: Determine whether the current time needs to be calculated for each partition in order from level 1 to level n-1; for each partition with level 'level', 1≤level≤n-1, the method for determining whether the current time needs to be calculated is: if the current processing time time≥t0 level Then a solution is needed, specifically based on t0. level Obtain the relevant parameters of the thermal network energy balance model for each node, and perform iterative simulations on all nodes of the partition. When all nodes in the partition satisfy the convergence criterion corresponding to that partition, then all nodes in that partition have reached convergence. Use the temperature corresponding to each node as the temperature result for the current processing time (t0). Finally, set t0... level Assigned the value t0 level +step level If the current processing time is time <t0 level If the partition does not require a solution, the temperature of each node remains constant.

[0063] Step S45: Assign the current processing time (time) to the value of time + step. n step n Let n be the time step corresponding to partition level n; based on the current processing time and the temperature convergence criterion corresponding to partition level n, perform iterative simulation on all nodes of partition level n to obtain the temperature corresponding to each node, and proceed to step S43.

[0064] In this embodiment, the iterative solution method is a conventional numerical solution method, including Jacobi iteration, Gauss-Seidel iteration, etc.; during the iteration process, publicly available iterative acceleration methods, including relaxation acceleration method, Aitken acceleration method, etc., can also be used.

[0065] like Figure 2 As shown, this invention proposes a multi-level simulation device for spacecraft temperature control zones, the device comprising:

[0066] Modeling module: Configured to build a thermal analysis model for the spacecraft; determine the nodes of the thermal analysis model of the spacecraft, with each node representing the temperature of a different part of the spacecraft; based on the thermal analysis model and the total number of nodes, establish an energy balance model of the node thermal network;

[0067] Partitioning module: configured to divide the nodes into multi-level partitions based on the energy balance model and the allowable temperature range of each node, with each partition corresponding to a level and including several nodes;

[0068] The first simulation module is configured to set a temperature convergence criterion for each partition, wherein the temperature convergence criterion is the temperature criterion for all nodes corresponding to each partition to reach convergence.

[0069] The second simulation module is configured to set a uniform transient solution end time for all partitions and set a time step for each partition. The time step indicates the increment in time for each solution of the partition when the transient iterative calculation is performed before the solution end time. Based on the temperature convergence criterion corresponding to each partition and the current solution time, transient heat transfer iterative simulation is performed on each partition in sequence to obtain the temperature of each node at the current solution time.

[0070] The specific embodiments described above only illustrate the design principles of the present invention. The shapes and names of the components in this description may differ and are not limited. Therefore, those skilled in the art can modify or make equivalent substitutions to the technical solutions described in the foregoing embodiments; and these modifications and substitutions do not depart from the inventive spirit and technical solutions of the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A multi-level simulation method for temperature control zones in spacecraft, characterized in that, The method includes the following steps: Step S1: Establish a thermal analysis model for the spacecraft; determine the nodes of the thermal analysis model, where each node represents the temperature of a different part of the spacecraft; based on the thermal analysis model and the total number of nodes, establish an energy balance model for the node thermal network; Step S2: Based on the energy balance model and the allowable temperature range of each node, the nodes are divided into multi-level partitions, each partition corresponding to a level and including several nodes; Step S3: Set a temperature convergence criterion for each partition, wherein the temperature convergence criterion is the temperature criterion for all nodes corresponding to each partition to reach convergence. Step S4: Set a uniform transient solution end time for all partitions, and set a time step for each partition. The time step indicates the increment in time for each solution of the partition when the transient iterative calculation is performed before the solution end time. Based on the temperature convergence criterion corresponding to each partition and the current solution time, perform transient heat transfer iterative simulation on each partition in sequence to obtain the temperature of each node at the current solution time. Step S4: Set a uniform transient solution end time for all partitions, and set a time step for each partition. The time step indicates the increment in time for each solution operation when the transient iteration calculation for that partition is less than the solution end time. Based on the temperature convergence criterion corresponding to each partition and the current solution time, perform transient heat transfer iterative simulation on each partition sequentially to obtain the temperature of each node at the current solution time, including: Step S41: Set a uniform transient solution end time for all partitions, and set a time step for each partition. The time step indicates the time increment for each solution operation when the transient iteration calculation for that partition is less than the solution end time. The higher the level of the partition, the larger the corresponding time step. num The smaller the value; Step S42: Set the current time to time, and assign the initial value of the current time time to step. n step n Let n be the time step for the partition of level n; set a baseline iteration time t0 for each partition. num The initial value is step num step num This represents the time step corresponding to the partition with level num; Step S43: If time is greater than the solution completion time, the method ends; otherwise, proceed to step S44. Step S44: Determine whether the current time needs to be calculated sequentially, according to the partitions from level 1 to level n-1; where, for each partition with level 'level', The method to determine whether the current time needs to be calculated is: if the current processing time time ≥ t0 level Then a solution is needed, specifically based on t0. level Obtain the relevant parameters of the thermal network energy balance model for each node, and perform iterative simulations on all nodes of the partition. When all nodes in the partition satisfy the convergence criterion corresponding to that partition, then all nodes in that partition have reached convergence. Use the temperature corresponding to each node as the temperature result for the current processing time (t0). Finally, set t0... level Assigned the value t0 level +step level If the current processing time is time <t0 level If the partition does not require a solution, the temperature of each node remains constant. Step S45: Assign the current processing time (time) to the value of time + step. n step n Let n be the time step corresponding to partition level n; based on the current processing time and the temperature convergence criterion corresponding to partition level n, perform iterative simulation on all nodes of partition level n to obtain the temperature corresponding to each node, and proceed to step S43.

2. The method as described in claim 1, characterized in that, The energy balance model of the nodal thermal network is as follows: Where i and j represent nodes, and N is the total number of nodes. i For nodes i temperature, i For nodes i quality i For nodes i Specific heat capacity, For time, For nodes i The absorbed heat, including the nodes i Heat generated by its own processes, temperature-controlled heating, and heat received from the outside. j For nodes j Temperature; and Let J represent the linear thermal conductance and the fourth-order nonlinear radiative thermal conductance from node J to node i, respectively. For nodes i The fourth power of the temperature, For nodes j The fourth power of the temperature, node j and i The relationship between nodes is i Node absorption j Node to Node i Heat conducted through conduction.

3. The method as described in claim 2, characterized in that, In step S2, based on the allowable temperature range of each node, the maximum value of the lower limit of the allowable lower temperature of each node is taken as the first lower limit, and the minimum value of the upper limit of the allowable upper temperature of each node is taken as the first upper limit. The absolute value of the difference between the first upper limit and the first lower limit is taken as the partitioning criterion, denoted as TT. TT is divided into n levels. The node partition with the largest temperature range corresponding to the partitioning criterion is defined as level 1, and the node partition with the smallest temperature range corresponding to the partitioning criterion is defined as level n. , num For partition level, num The higher the number, the higher the level.

4. The method as described in claim 3, characterized in that, Step S3: Set a temperature convergence criterion for each partition. The temperature convergence criterion is the temperature criterion for all nodes corresponding to each partition to reach convergence. Convergence means that the absolute value of the temperature difference between the current iteration step and the previous iteration step of a node is less than the temperature convergence criterion. The higher the level of the partition, the smaller the convergence criterion for that partition.

5. The method according to any one of claims 1-4, characterized in that, The thermal analysis model is a model that can characterize the heat transfer physical processes in various parts of the spacecraft.

6. A multi-level simulation device for spacecraft temperature control zones, characterized in that, The apparatus is used to implement the method as described in any one of claims 1-5, comprising: Modeling module: Configured to build a thermal analysis model for the spacecraft; determine the nodes of the thermal analysis model, each node representing the temperature of a different part of the spacecraft; based on the thermal analysis model and the total number of nodes, establish an energy balance model of the node thermal network; Partitioning module: configured to divide the nodes into multi-level partitions based on the energy balance model and the allowable temperature range of each node, with each partition corresponding to a level and including several nodes; The first simulation module is configured to set a temperature convergence criterion for each partition, wherein the temperature convergence criterion is the temperature criterion for all nodes corresponding to each partition to reach convergence. The second simulation module is configured to set a uniform transient solution end time for all partitions and set a time step for each partition. The time step indicates the increment in time for each solution of the partition when the transient iterative calculation is performed before the solution end time. Based on the temperature convergence criterion corresponding to each partition and the current solution time, transient heat transfer iterative simulation is performed on each partition in sequence to obtain the temperature of each node at the current solution time.

7. A computer-readable storage medium storing a plurality of instructions; the plurality of instructions being loaded by a processor and executing the method as claimed in any one of claims 1-5.

8. An electronic device, characterized in that, The electronic device includes: A processor is used to execute multiple instructions; Memory, used to store multiple instructions; The plurality of instructions are to be stored in the memory and loaded by the processor and executed as described in any one of claims 1-5.

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