A method, device, equipment and medium for determining coupling boundary of high altitude engine

Abstract

The present application discloses a coupling boundary determination method, device, equipment and medium for a high-altitude engine, which relates to the field of rarefied fluid mechanics. The method comprises: by setting the Knudsen value and the Knudsen threshold, selecting the initial grid unit set, extracting the coupling boundary position by the infection method, if the Knudsen value of the adjacent grid unit in the activated state is less than the Knudsen threshold, it is marked as an inactive state, if the Knudsen value of the adjacent grid unit in the activated state is greater than or equal to the Knudsen threshold, then the boundary between the inactive grid unit and the activated grid unit is determined as the first coupling boundary, and then the internal islands and boundary denoising are eliminated. The method can identify and dynamically adjust the coupling boundary position, and significantly simplify the complexity of continuous and rarefied cross-domain coupling numerical simulation based on the change of flow field parameters.

Description

Technical Field

[0001] The present application relates to the field of rarefied fluid mechanics, and in particular to a method, device, equipment and medium for determining the coupling boundary of a high-altitude engine. Background Art

[0002] In the field of rarefied fluid mechanics, engine plumes in a high vacuum environment can cause non-negligible "pollution" effects on spacecraft, such as aerodynamics and electromagnetic interference. Due to the limitations of the high vacuum environment, ground experiments on engine plumes are very difficult and costly. Numerical simulation is an important research and analysis method.

[0003] Currently, a common approach in engineering is to couple a continuous flow solution based on CFD (Computational Fluid Dynamics) with a rarefied flow solution based on DSMC (Direct Simulation of Monte Carlo). A key issue in this coupled approach is determining the location of the coupling boundary. Two approaches are commonly used: manual specification, which is relatively simple to calculate and set up, and automatic boundary identification based on a predefined criterion, such as the local Knudsen number.

[0004] However, the manually specified method lacks flexibility and adaptability to flow field changes and requires repeated human intervention. The method of automatically identifying boundaries based on set judgment criteria is not universal and will also identify far-field high vacuum areas as continuous flow areas. Summary of the Invention

[0005] The present application provides a method, device, equipment and medium for determining the coupling boundary of a high-altitude engine, which can more accurately identify and dynamically adjust the coupling boundary position, and significantly simplify the complexity of numerical simulation of continuous and rarefied cross-domain coupling based on changes in flow field parameters.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a method for determining a coupling boundary of a high-altitude engine, which is applied to a processing device, and the method comprises:

[0008] simulating the computational domain of the high-altitude engine to obtain simulation results;

[0009] Determining an initial grid cell set from the simulation results, and marking an initial grid cell in the initial grid cell set as an inactive state, wherein the inactive state indicates that the grid cell is in a continuous flow region;

[0010] Determine whether t is less than a first iteration number threshold, where t is the first iteration number and t is a positive integer; determine the first adjacent grid cell set based on the initial grid cell set;

[0011] If t is less than the first iteration number threshold, determining a t+1th adjacent grid cell set adjacent to the inactive grid cell in the tth adjacent grid cell set, and marking the grid cells in the t+1th adjacent grid cell set that are in an active state and whose Knudsen values ​​are less than the Knudsen threshold as inactive; the active state indicates that the grid cell is in a discontinuous flow region;

[0012] If t is greater than or equal to the first iteration number threshold, a boundary between the inactive grid cell and the active grid cell is determined as a first coupling boundary.

[0013] In some possible implementations, after determining the boundary between the inactive grid cell and the active grid cell as the first coupling boundary, the method further includes:

[0014] Determining whether there is a grid cell having a Mach number less than a Mach threshold in the s-th layer of grid cell set, wherein the first layer of grid cell set is a set of outermost grid cells in a continuous flow region adjacent to the first coupling boundary;

[0015] If there is a grid cell with a Mach number less than the Mach threshold in the s-th grid cell set, the grid cell with the Mach number less than the Mach threshold is marked as an activated state; and an s+1-th grid cell set adjacent to the activated grid cell in the s-th grid cell set is determined;

[0016] If there is no grid cell with a Mach number less than the Mach threshold in the s-th layer grid cell set, the boundary between the grid cell in the inactive state and the grid cell in the active state is determined as the second coupling boundary.

[0017] In some possible implementations, the method further includes:

[0018] The grid cells in the area within the second coupling boundary are marked as inactive, and the grid cells in the area outside the second coupling boundary are marked as active.

[0019] In some possible implementations, the method further includes:

[0020] determining a first target grid cell adjacent to the second coupling boundary;

[0021] Obtaining a first number of inactive grid cells and a second number of active grid cells adjacent to the first target grid cell;

[0022] If the first number is less than the second number, marking the first target grid unit as activated.

[0023] In some possible implementations, determining an initial grid unit set from the simulation results includes:

[0024] The grid cells between the engine inlet and the nozzle outlet in the simulation results are determined as an initial grid cell set.

[0025] In some possible implementations, determining the grid cells between the engine inlet and the nozzle outlet in the simulation results as the initial grid cell set includes:

[0026] Obtaining a Knudsen value of a second target grid cell between an engine inlet and a nozzle outlet in the simulation result;

[0027] Determining whether the Knudsen value of the second target grid cell is less than a Knudsen threshold;

[0028] If the Knudsen value of the second target grid cell is less than the Knudsen threshold, the second target grid cell is determined as the initial grid cell in the initial grid cell set.

[0029] In a second aspect, the present application provides a device for determining a coupling boundary of a high-altitude engine, the device comprising:

[0030] The simulation module is used to simulate the computational domain of the high-altitude engine and obtain simulation results;

[0031] a calibration module, configured to determine an initial grid cell set from the simulation results, and mark the initial grid cells in the initial grid cell set as being in an inactive state, wherein the inactive state indicates that the grid cells are in a continuous flow region;

[0032] a judgment module, configured to judge whether t is less than a first iteration number threshold, where t is the first iteration number and t is a positive integer; a first adjacent grid cell set is determined based on the initial grid cell set; if t is less than the first iteration number threshold, a t+1th adjacent grid cell set adjacent to the inactive grid cell in the tth adjacent grid cell set is determined, and grid cells in the t+1th adjacent grid cell set that are in an active state and have a Knudsen value less than the Knudsen threshold are marked as inactive; the active state indicates that the grid cell is in a discontinuous flow region;

[0033] A determination module is configured to determine a boundary between an inactive grid cell and an active grid cell as a first coupling boundary if t is greater than or equal to the first iteration number threshold.

[0034] In some possible implementations, after determining the boundary between the inactive grid unit and the active grid unit as the first coupling boundary, the apparatus further includes:

[0035] A judgment module is configured to judge whether there are grid cells with Mach numbers less than a Mach threshold in the s-th grid cell set, wherein the 1st grid cell set is a set of grid cells in the outermost layer of the continuous flow region adjacent to the first coupling boundary; if there are grid cells with Mach numbers less than the Mach threshold in the s-th grid cell set, the grid cells with Mach numbers less than the Mach threshold are marked as being in an activated state; determine an s+1th grid cell set adjacent to the grid cells in the s-th grid cell set that are in an activated state; and if there are no grid cells with Mach numbers less than the Mach threshold in the s-th grid cell set, determine the boundary between the inactive grid cells and the active grid cells as a second coupling boundary.

[0036] In a third aspect, the present application provides a computing device, including a memory and a processor;

[0037] One or more computer programs are stored in the memory, and the one or more computer programs include instructions; when the instructions are executed by the processor, the computing device executes the method as described in any one of the first aspects.

[0038] In a fourth aspect, the present application provides a computer-readable storage medium for storing a computer program for executing the method as described in any one of the first aspects.

[0039] It can be seen from the above technical solution that this application has at least the following beneficial effects:

[0040] In the present application, a processing device simulates the computational domain of a high-altitude engine to obtain simulation results, determines an initial grid cell set based on the simulation results, marks the initial grid cell in the initial grid cell set as inactive, determines whether the Knudsen value of an active grid cell adjacent to the initial grid cell is less than a Knudsen threshold, and if the Knudsen value of the adjacent active grid cell is less than the Knudsen threshold, marks it as inactive, and if the Knudsen value of the adjacent active grid cell is greater than or equal to the Knudsen threshold, determines the boundary between the inactive grid cell and the active grid cell as the first coupling boundary. In traditional schemes, two methods are usually used to determine the location of the coupling boundary. One is manual designation, which is relatively simple to calculate and set, and the other is automatic identification of the boundary based on a set judgment criterion, such as the most commonly used local Knudsen number criterion. However, the manually specified method lacks flexibility and adaptability to flow field changes, and requires repeated human intervention. The method of automatically identifying boundaries based on the set judgment criteria is not universal and will also identify the far-field high vacuum area as a continuous flow area. It can be seen that in this application, starting from the initial grid unit, layer-by-layer judgment is performed to determine the state of the grid unit, thereby dividing the interface between the grid unit in the inactive state and the grid unit in the active state, and determining the interface as the first coupling boundary. It can be seen that the present application can identify and dynamically adjust the coupling boundary position, and based on the changes in flow field parameters, significantly simplify the complexity of the continuous and rarefied cross-domain coupling numerical simulation.

[0041] It should be understood that the description of technical features, technical solutions, beneficial effects or similar language in this application does not imply that all features and advantages can be realized in any single embodiment. On the contrary, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution or beneficial effect is included in at least one embodiment. Therefore, the description of a technical feature, technical solution or beneficial effect in this specification does not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions and beneficial effects described in the present embodiment can also be combined in any appropriate manner. Those skilled in the art will understand that the embodiment can be implemented without one or more specific technical features, technical solutions or beneficial effects of a specific embodiment. In other embodiments, additional technical features and beneficial effects can also be identified in specific embodiments that do not embody all embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A flow chart of a method for determining a coupling boundary of a high-altitude engine provided in an embodiment of the present application;

[0043] Figure 2 A schematic diagram of an initial grid unit set provided in an embodiment of the present application;

[0044] Figure 3 A schematic diagram of a first coupling boundary provided in an embodiment of the present application;

[0045] Figure 4 A schematic diagram of the second coupling boundary after removing the isolated island provided in an embodiment of the present application;

[0046] Figure 5 A schematic diagram of a third coupling boundary provided in an embodiment of the present application;

[0047] Figure 6 A schematic diagram of a coupling boundary determination device for a high-altitude engine provided in an embodiment of the present application;

[0048] Figure 7 A schematic diagram of a computing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The terms "first", "second" and "third" in this application specification and the accompanying drawings are used to distinguish different objects rather than to limit a specific order.

[0050] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0051] To make the description of the following embodiments clear and concise, a brief introduction to the related technologies is first given:

[0052] The continuous flow region refers to the region of gas flow where the mean free path of gas molecules is much smaller than characteristic dimensions in the flow field (such as channel dimensions and object size), allowing the gas to be treated as a continuous medium. Within this region, the discreteness and mutual collisions of gas molecules have negligible effects on flow characteristics, and the flow behavior can be described using the classical equations of continuum fluid mechanics. In the continuous flow region, physical quantities of the fluid (such as velocity, pressure, and density) vary continuously in space and time, without discontinuities or jumps.

[0053] The continuum flow regime is one of the most fundamental and common flow domains in fluid mechanics, encompassing most fluid flow problems encountered in engineering practice and natural phenomena. Within this regime, factors such as fluid viscosity, inertia, and pressure gradients influence flow characteristics, requiring solutions based on fundamental equations and boundary conditions in fluid mechanics.

[0054] The rarefied flow region refers to a region in a gas flow where the mean free path between gas molecules is no longer significantly less than 1 compared to characteristic scales in the flow field (such as object size and boundary layer thickness). This results in the discreteness of gas molecules and their mutual collisions having a significant impact on the flow characteristics. In this region, the frequency of collisions between gas molecules is comparable to or lower than the frequency of collisions between molecules and surfaces, causing the flow behavior to deviate from the description of traditional continuum fluid mechanics.

[0055] At present, there are usually two methods to determine the location of the coupling boundary between the continuous flow region and the rarefied flow region. One is manual specification, which is relatively simple to calculate and set up; the other is automatic identification of the boundary based on set judgment criteria, such as the most commonly used local Knudsen number criterion.

[0056] However, the manually specified method lacks flexibility and adaptability to flow field changes and requires repeated human intervention. The method of automatically identifying boundaries based on set judgment criteria is not universal and will also identify far-field high vacuum areas as continuous flow areas.

[0057] In view of this, an embodiment of the present application provides a method for determining the coupling boundary of a high-altitude engine. The method can be applied to a processing device, which can be a terminal or a server. Terminals include but are not limited to smartphones, tablets, laptops, personal digital assistants, or smart wearable devices. The server can be a cloud server, such as a central server in a central cloud computing cluster, or an edge server in an edge cloud computing cluster. Of course, the server can also be a server in a local data center. A local data center refers to a data center directly controlled by the user.

[0058] In the method, a processing device simulates a computational domain of a high-altitude engine to obtain simulation results, determines an initial grid cell set based on the simulation results, marks an initial grid cell in the initial grid cell set as inactive, determines whether a Knudsen value of an active grid cell adjacent to the initial grid cell is less than a Knudsen threshold, marks the initial grid cell as inactive if the Knudsen value of the adjacent active grid cell is less than the Knudsen threshold, and determines a boundary between the inactive grid cell and the active grid cell as a first coupling boundary if the Knudsen value of the adjacent active grid cell is greater than or equal to the Knudsen threshold.

[0059] In order to make the technical solution of this application clearer and easier to understand, the technical solution of this application is introduced below with reference to the accompanying drawings. Figure 1 As shown, this figure is a flow chart of a method for determining the coupling boundary of a high-altitude engine provided in an embodiment of the present application.

[0060] The embodiment of the present application is applied to a processing device, and the coupling boundary determination method of the high-altitude engine includes:

[0061] S101. The processing device simulates the calculation domain of the high-altitude engine.

[0062] Before performing high-altitude engine simulation, the computational domain must first be accurately defined. The computational domain is usually a virtual space that contains the engine body and its surrounding flow field environment. It must be large enough to accommodate all important flow phenomena generated when the engine is running, such as airflow capture in the intake duct, the combustion process in the combustion chamber, and exhaust expansion in the tail nozzle. At the same time, considering the particularity of the high-altitude environment, such as low pressure, low temperature, high wind speed and other conditions, the setting of the computational domain must also take into account the impact of these environmental factors on engine performance. The processing device then performs simulation based on the obtained computational domain. In some embodiments, the processing device can simulate the high-altitude engine and obtain the simulation results corresponding to the high-altitude engine.

[0063] S102: The processing device determines an initial grid unit set from the simulation results.

[0064] The grid cells between the engine inlet and the nozzle outlet in the simulation results are determined as the initial grid cell set, such as Figure 2 As shown in FIG, this figure is a schematic diagram of an initial grid unit set provided in an embodiment of the present application.

[0065] All initial grid cells in the initial grid cell set should be in the continuous flow region. The Knudsen value of the second target grid cell between the engine inlet and the nozzle outlet in the simulation results is obtained. The Knudsen threshold is set to 0.005 to ensure that the Knudsen value of all initial grid cells is less than 0.005.

[0066] First, a continuous assumption failure criterion is defined. In this application, the local Knudsen number criterion is adopted, and formula (1) is obtained:

[0067] (1)

[0068] in, is the local Knudsen number, is the molecular free path, Based on local parameters The characteristic length, local parameter Including density, pressure and velocity.

[0069] Molecular free path It can be calculated by formula (2):

[0070] (2)

[0071] in, is the molecular mass, is the molecular diameter, is the continuous flow density.

[0072] Based on local parameters Characteristic length Calculated by formula (3):

[0073] (3)

[0074] Extract the distribution of density, pressure and velocity from the simulation results and calculate the local parameters The gradient of , can be seen from formula (4):

[0075]

[0076] Where n is the local direction vector.

[0077] And take local parameters The maximum value of the gradient, as shown in formula (5):

[0078] (5)

[0079] in, is the speed of the high-altitude engine, speed Take the absolute value , is the pressure of the continuous flow, u is the velocity in the X direction, v is the velocity in the Y direction, and w is the velocity in the Z direction. Assume a minimum value , if the speed is too low (i.e. ), in order to avoid obviously unreasonable characteristic length values ​​caused by numerical errors, the velocity can be eliminated and only density and pressure can be considered.

[0080] Determine whether the Knudsen value of the second target grid cell is less than a Knudsen threshold, where the Knudsen threshold is set to 0.005 in S102;

[0081] If the Knudsen value of the second target grid cell is less than the Knudsen threshold, the second target grid cell is determined as an initial grid cell in the initial grid cell set, and the initial grid cell in the initial grid cell set is marked as an inactive state, where the inactive state indicates that the grid cell is in a continuous flow area.

[0082] S103: The processing device determines whether t is less than a first iteration number threshold.

[0083] t is the first iteration number, and t is a positive integer; the first adjacent grid unit set is determined based on the initial grid unit set.

[0084] It is determined whether t is less than a first iteration number threshold to obtain a first determination result.

[0085] If the first judgment result indicates that t is less than the first iteration number threshold, execute S104;

[0086] If the first judgment result indicates that t is greater than the first iteration number threshold, S106 is executed.

[0087] S104: The processing device determines a t+1th adjacent grid cell set adjacent to the inactive grid cell in the tth adjacent grid cell set.

[0088] If t is less than the first iteration number threshold, then determine the t+1th adjacent grid cell set adjacent to the inactive grid cell in the tth adjacent grid cell set. All grid cells in the tth adjacent grid cell set are in the inactive state. Therefore, it is necessary to further determine the state of the grid cells in the t+1th adjacent grid cell set. If the Knudsen value of the grid cells in the t+1th adjacent grid cell set is less than the Knudsen threshold, execute S105.

[0089] S105 : The processing device marks the t+1th adjacent grid cells that are in an activated state and whose Knudsen values ​​are smaller than the Knudsen threshold as in an inactivated state.

[0090] Starting from the initial grid cell, the infection is carried out layer by layer to the adjacent grid cells. If the adjacent grid cell is already in an inactive state, it is skipped. If the adjacent grid cell is in an active state, it is infected and marked as inactive. The active state indicates that the grid cell is in a discontinuous flow area, which is a rarefied flow area.

[0091] The above process is repeated until the Knudsen values ​​of all grid cells on the boundary reach the Knudsen threshold, and then S106 is executed.

[0092] S106: The processing device determines a boundary between an inactive grid unit and an active grid unit as a first coupling boundary.

[0093] If t is greater than or equal to the first iteration number threshold, the boundary between the inactive grid unit and the active grid unit is determined as the first coupling boundary. Figure 3 As shown, the figure is a schematic diagram of a first coupling boundary provided in an embodiment of the present application. In the figure, it can be seen that the boundary line where the black area and the white area meet is the first coupling boundary. There are a few white grid units in the black area in the figure, and the grid units are islands.

[0094] The above operation can ensure that the continuous flow region is located in the jet zone downstream of the engine nozzle, avoiding infinite extension and preventing the far-field incoming flow region from being judged as a continuous flow region. It can ensure the rationality of the identified boundary position in the engine plume problem.

[0095] After determining the first coupling boundary, it is also necessary to determine whether there is a grid cell with a Mach number less than the Mach threshold in the s-th layer grid cell set, wherein the first layer grid cell set is a set of outermost grid cells in the continuous flow region adjacent to the first coupling boundary.

[0096] In the embodiment of the present application, the first coupling boundary is obtained by determining the Knudsen value. In order to make the boundary between the continuous flow region and the rarefied flow region more accurate, the relationship between the Mach number and the predicted Mach number of the grid cells is determined one by one starting from the outer grid cell set, thereby obtaining a more accurate coupling boundary.

[0097] S107 . The processing device determines whether there is a grid unit with a Mach number less than a Mach threshold in the grid unit set of the s-th layer.

[0098] If there is a grid cell with a Mach number less than the Mach threshold in the s-th layer grid cell set, then execute S108;

[0099] If there is no grid cell with a Mach number less than the Mach threshold in the s-th layer grid cell set, S109 is executed.

[0100] S108. The processing device marks the grid cells whose Mach numbers are less than the Mach threshold as being in an activated state.

[0101] The grid cells with Mach numbers less than the Mach threshold are marked as active, and the grid cell set of the s+1th layer adjacent to the grid cells in the active state in the grid cell set of the sth layer is determined. The determination is continued until no more grid cells with Mach numbers less than the Mach threshold appear on the boundary, and then S109 is executed.

[0102] S109: The processing device determines a boundary between the grid unit in the inactive state and the grid unit in the active state as a second coupling boundary.

[0103] After determining the second coupling boundary, islands may exist within the continuous and rarefied flow regions. This means that a small number of active cells cluster within the inactive cells in the continuous flow region, and a small number of inactive cells cluster within the active cells in the rarefied region. This can cause disconnection between computational domains, affecting computational stability. Therefore, further efforts are needed to eliminate islands within these regions.

[0104] First, all grid cells are relabeled as active cells. Then, the infection method is used, starting from the far-field boundary outside the computational domain and infecting inward layer by layer until the second coupling boundary is reached. The grid cells within the second coupling boundary are marked as inactive, and the grid cells outside the second coupling boundary are marked as active.

[0105] This operation method can effectively remove the island, making the two sides of the second coupling boundary pure continuous flow area or pure rarefied flow area. Figure 4 As shown, this figure is a schematic diagram of the second coupling boundary after removing the island provided in an embodiment of the present application.

[0106] In order to make the shape of the second coupling boundary smoother and improve the calculation stability, the second coupling boundary is further smoothed. The method includes:

[0107] determining a first target grid cell adjacent to the second coupling boundary;

[0108] Obtaining a first number of inactive grid cells and a second number of active grid cells adjacent to the first target grid cell;

[0109] If the first number is smaller than the second number, the first target grid unit is marked as an activated state; if the first number is larger than the second number, the first target grid unit is marked as an inactivated state.

[0110] Repeat the above operation until the maximum number of smoothing times is reached. In the embodiment of the present application, in order to ensure the calculation efficiency, the maximum number of smoothing times is set to 10 times, thereby determining the final coupling boundary, and determining the coupling boundary as the third coupling boundary, such as Figure 5 As shown, this figure is a schematic diagram of a third coupling boundary provided in an embodiment of the present application.

[0111] Based on the above content, the processing equipment simulates the computational domain of the high-altitude engine to obtain simulation results, determines the initial grid cell set according to the simulation results, marks the initial grid cell in the initial grid cell set as inactive, determines whether the Knudsen value of the active grid cell adjacent to the initial grid cell is less than the Knudsen threshold, if the Knudsen value of the adjacent active grid cell is less than the Knudsen threshold, it is marked as inactive, if the Knudsen value of the adjacent active grid cell is greater than or equal to the Knudsen threshold, then the boundary between the inactive grid cell and the active grid cell is determined as the first coupling boundary. Therefore, starting from the initial grid cell, the present application makes a layer-by-layer judgment to determine the state of the grid cell, thereby dividing the interface between the inactive grid cell and the active grid cell, and determining the interface as the first coupling boundary. It can be seen that the present application can identify and dynamically adjust the coupling boundary position, and significantly simplify the complexity of the continuous and rarefied cross-domain coupling numerical simulation based on the change of flow field parameters.

[0112] The embodiment of the present application also provides a coupling boundary determination device for a high-altitude engine, such as Figure 6 As shown in the figure, a schematic diagram of a coupling boundary determination device for a high-altitude engine provided by an embodiment of the present application, the device includes: a simulation module 601, a marking module 602, a judgment module 603 and a determination module 604;

[0113] A simulation module 601 is used to simulate the calculation domain of the high-altitude engine to obtain simulation results;

[0114] a marking module 602 for determining an initial grid cell set from the simulation results, and marking an initial grid cell in the initial grid cell set as an inactive state, wherein the inactive state indicates that the grid cell is in a continuous flow region;

[0115] Determination module 603 is configured to determine whether t is less than a first iteration number threshold, where t is the first iteration number and is a positive integer; the first adjacent grid cell set is determined based on the initial grid cell set; if t is less than the first iteration number threshold, the t+1th adjacent grid cell set adjacent to the inactive grid cell in the tth adjacent grid cell set is determined, and grid cells in the t+1th adjacent grid cell set that are in an active state and have a Knudsen value less than the Knudsen threshold are marked as inactive; the active state indicates that the grid cell is in a discontinuous flow region;

[0116] The determining module 604 is configured to determine a boundary between an inactive grid cell and an active grid cell as a first coupling boundary if t is greater than or equal to the first iteration number threshold.

[0117] The present application also provides a computing device. Figure 7 As shown, this figure is a schematic diagram of a computing device provided by an embodiment of the present application, wherein the computing device 700 includes a bus 701, a processor 702, a communication interface 703, and a memory 704. The processor 702, the memory 704, and the communication interface 703 communicate with each other via the bus 701.

[0118] The bus 701 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 7 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0119] The processor 702 may be any one or more of a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor (MP), or a digital signal processor (DSP).

[0120] The communication interface 703 is used for external communication. For example, when the computing device is a first switch, the communication interface 703 can be used for communication between the first switch and the first user terminal, or between the first switch and the second switch.

[0121] The memory 704 may include volatile memory, such as random access memory (RAM). The memory 704 may also include non-volatile memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive (SSD).

[0122] The memory 704 stores executable codes, and the processor 702 executes the executable codes to perform the aforementioned method for determining the coupling boundary of the high-altitude engine.

[0123] Embodiments of the present application also provide a computer-readable storage medium. The computer-readable storage medium can be any available medium capable of being stored by a computing device, or a data storage device such as a data center that contains one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, hard disk, or magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive). The computer-readable storage medium includes instructions that instruct the computing device to execute the method for determining the coupling boundary of a high-altitude engine.

[0124] The present application also provides a computer program product comprising one or more computer instructions that, when loaded and executed on a computing device, fully or partially generate the process or function described in the present application.

[0125] The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer or data center to another website, computer or data center via wired (e.g., coaxial cable, optical fiber) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0126] When the computer program product is executed by a computer, the computer performs any of the aforementioned methods for determining the coupling boundary of a high-altitude engine. The computer program product may be a software installation package. When any of the aforementioned methods for determining the coupling boundary of a high-altitude engine is required, the computer program product may be downloaded and executed on the computer.

[0127] The descriptions of the processes or structures corresponding to the above figures have different emphases. For parts that are not described in detail in a certain process or structure, please refer to the relevant descriptions of other processes or structures.

[0128] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical scope disclosed in the present application should be included in the protection scope of the present application.

Claims

1. A method for determining the coupling boundary of a high-altitude engine, characterized in that: Applied to a processing device, the method comprises: Simulate the computational domain of the high-altitude engine and obtain simulation results; Determine an initial grid cell set from the simulation results, and mark the initial grid cells in the initial grid cell set as inactive, wherein the inactive state indicates that the grid cells are in a continuous flow region; Determine whether t is less than a first iteration number threshold, where t is the first iteration number and t is a positive integer; the first adjacent grid unit set is determined based on the initial grid unit set; If t is less than the first iteration number threshold, determine the t+1th adjacent grid cell set adjacent to the grid cell in the inactive state in the tth adjacent grid cell set, and mark the grid cells in the t+1th adjacent grid cell set that are in the active state and whose Knudsen values ​​are less than the Knudsen threshold as inactive; the active state indicates that the grid cell is in a discontinuous flow area; If t is greater than or equal to the first iteration number threshold, determining the boundary between the grid unit in the inactive state and the grid unit in the active state as the first coupling boundary; Determine whether there is a grid unit having a Mach number less than a Mach threshold in the s-th grid unit set, wherein the first-layer grid unit set is a set of outermost grid units in a continuous flow region adjacent to the first coupling boundary; If there are grid cells with Mach numbers less than the Mach threshold in the s-th grid cell set, the grid cells with Mach numbers less than the Mach threshold are marked as activated; and an s+1-th grid cell set adjacent to the activated grid cells in the s-th grid cell set is determined; If there is no grid unit with a Mach number less than the Mach threshold in the s-th layer grid unit set, the boundary between the grid unit in the inactive state and the grid unit in the active state is determined as the second coupling boundary.

2. The method according to claim 1, characterized in that: The method further comprises: The grid cells in the area within the second coupling boundary are marked as inactive, and the grid cells in the area outside the second coupling boundary are marked as active.

3. The method according to claim 2, characterized in that The method further comprises: determining a first target grid cell adjacent to the second coupling boundary; Acquire a first number of inactive grid cells and a second number of active grid cells adjacent to the first target grid cell; If the first number is less than the second number, marking the first target grid unit as activated.

4. The method according to claim 1, characterized in that: The step of determining an initial grid unit set from the simulation results comprises: The grid cells between the engine inlet and the nozzle outlet in the simulation results are determined as an initial grid cell set.

5. The method according to claim 4, characterized in that The step of determining the grid cells between the engine inlet and the nozzle outlet in the simulation result as the initial grid cell set includes: Obtaining a Knudsen value of a second target grid cell between an engine inlet and a nozzle outlet in the simulation result; Determining whether the Knudsen value of the second target grid cell is less than a Knudsen threshold; If the Knudsen value of the second target grid cell is less than the Knudsen threshold, the second target grid cell is determined as an initial grid cell in the initial grid cell set.

6. A coupling boundary determination device for a high altitude engine, characterized in that: The device comprises: The simulation module is used to simulate the computational domain of the high-altitude engine and obtain simulation results; A calibration module, used for determining an initial grid unit set from the simulation results, and marking the initial grid units in the initial grid unit set as an inactive state, wherein the inactive state indicates that the grid units are in a continuous flow region; A judgment module, used to judge whether t is less than a first iteration number threshold, t is the first iteration number, and t is a positive integer; the first adjacent grid cell set is determined based on the initial grid cell set; if t is less than the first iteration number threshold, the t+1th adjacent grid cell set adjacent to the grid cell in the inactive state in the tth adjacent grid cell set is determined, and the grid cell in the t+1th adjacent grid cell set that is in the active state and whose Knudsen value is less than the Knudsen threshold is marked as an inactive state; the active state indicates that the grid cell is in a discontinuous flow area; a determination module, configured to determine a boundary between a grid unit in an inactive state and a grid unit in an active state as a first coupling boundary if t is greater than or equal to the first iteration number threshold; A judgment module is used to judge whether there are grid cells with Mach numbers less than the Mach threshold in the s-th grid cell set, wherein the 1st grid cell set is a set of outermost grid cells in the continuous flow region adjacent to the first coupling boundary; if there are grid cells with Mach numbers less than the Mach threshold in the s-th grid cell set, the grid cells with Mach numbers less than the Mach threshold are marked as activated; an s+1th grid cell set adjacent to the grid cells in the s-th grid cell set in the activated state is determined; if there are no grid cells with Mach numbers less than the Mach threshold in the s-th grid cell set, the boundary between the grid cells in the inactive state and the grid cells in the activated state is determined as the second coupling boundary.

7. A computing device, characterized in that including memory and processor; One or more computer programs are stored in the memory, and the one or more computer programs include instructions; when the instructions are executed by the processor, the computing device executes the method as claimed in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store a computer program, and the computer program is used to execute the method according to any one of claims 1 to 5.

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