Numerical simulation method considering aircraft nitrogen injection

Abstract

The invention discloses a numerical simulation method considering aircraft nitrogen injection, which relates to the technical field of digital twinning and comprises the following steps of: constructing an initial digital twinning model of an aircraft fuel tank through computer aided design software and a computational fluid mechanics tool; the method comprises the following steps: acquiring flight data by using various sensors mounted on an airplane, recording vibration characteristics and real-time states of a box body, and outputting time sequence data; updating the digital twin model and coupling a vibration effect, generating a flow field change, and outputting a real-time simulation model reflecting a flight state; simulating nitrogen injection speed and concentration distribution, analyzing vibration influence, and outputting real-time flow field data; and generating a three-dimensional visual graph through a visual tool, calculating a nitrogen injection efficiency index, adding the nitrogen injection efficiency index into the three-dimensional visual graph, rendering and packaging the three-dimensional visual graph, transmitting the three-dimensional visual graph to a control center, and displaying the distribution state and the nitrogen injection efficiency index. According to the invention, the efficiency of airplane nitrogen injection numerical simulation is enhanced through the digital twin platform.

Description

Technical Field

[0001] The present invention relates to the technical field of digital twins, and in particular to a numerical simulation method considering nitrogen injection in an aircraft. Background Art

[0002] With the development of the aviation industry, nitrogen injection technology, as an effective inerting means, has been widely applied to aircraft fuel tanks to reduce the oxygen concentration, inhibit fuel volatility, and enhance flight safety. In recent years, the application of computational fluid dynamics in the aviation field has significantly advanced the numerical simulation research on the internal flow field and concentration distribution of fuel tanks. Typical methods include the finite volume method based on a static geometric model for solving and multiphase flow simulation. In addition, the rise of digital twin technology provides a new path for real-time monitoring and dynamic simulation. By integrating sensor data and virtual models, it can partially reflect the physical behavior under flight conditions. However, existing technologies mostly focus on static or quasi-static simulations, rarely considering the influence of vibration effects during flight on nitrogen injection, and data collection usually relies on offline analysis, making it difficult to achieve the unity of real-time performance and dynamic adaptability.

[0003] There are significant deficiencies in existing technologies when simulating nitrogen injection in aircraft, mainly reflected in the following aspects: First, there is a lack of systematic coupling of vibration effects, resulting in a large deviation between the simulation results and the actual flight state. Especially in high-frequency vibration or turbulent environments, the prediction accuracy of the flow field and concentration distribution is limited. Second, there is a lack of real-time performance. Traditional methods fail to fully utilize sensor data during flight to update the model, making it difficult to dynamically reflect the transient changes of nitrogen injection behavior. Third, the visualization and decision support capabilities are limited. Existing simulation results are mostly presented as static charts, lacking intuitive dynamic displays and real-time transmission of key indicators, which limits the rapid response of the control center to the state of the fuel tank. Summary of the Invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a numerical simulation method considering nitrogen injection in an aircraft to solve the problem of difficultly accurately simulating the dynamic behavior of nitrogen injection during aircraft flight.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] In the first aspect, the present invention provides a numerical simulation method considering nitrogen injection in an aircraft, which includes constructing an initial digital twin model of the aircraft fuel tank through computer-aided design software and computational fluid dynamics tools; collecting flight data using various sensors installed on the aircraft, recording the vibration characteristics and real-time status of the tank body, and outputting time series data; updating the digital twin model and coupling the vibration effect to generate a flow field change, and outputting a real-time simulation model reflecting the flight state; simulating the injection speed and concentration distribution of nitrogen, analyzing the vibration influence, and outputting real-time flow field data; generating three-dimensional visualization graphics through a visualization tool, calculating the nitrogen injection efficiency index and adding it to the three-dimensional visualization graphics, rendering and packaging the three-dimensional visualization graphics and transmitting them to the control center to display the distribution state and the nitrogen injection efficiency index.

[0008] As a preferred solution of the numerical simulation method considering nitrogen injection in an aircraft according to the present invention, wherein: the specific steps of constructing the initial digital twin model of the aircraft fuel tank through computer-aided design software and computational fluid dynamics tools are as follows,

[0009] Set the top center as the nitrogen injection point through SolidWorks and output a three-dimensional geometric model;

[0010] Import the three-dimensional geometric model into ANSYS Fluent;

[0011] Use the unstructured grid in ANSYS Fluent to spatially divide the partitions and the tank body in the three-dimensional geometric model and save it as a grid file;

[0012] Open the three-dimensional geometric model, initialize the flow rate, pressure and temperature of nitrogen injection and the oxygen concentration distribution of the fuel tank, and output an aircraft physical field configuration file;

[0013] Add vibration characteristics to the tank body at the top of the three-dimensional geometric model through boundary settings in ANSYS Fluent and output a boundary condition file;

[0014] Start the digital twin platform, configure the data interface and connect ANSYS Fluent with various sensors on the aircraft as the data receiving channel for initial simulation;

[0015] Load and integrate the three-dimensional geometric model, the grid file, the physical field configuration file, the boundary condition file and the data interface configuration file to generate a preliminary velocity distribution and concentration distribution, and output an initial digital twin model.

[0016] As a preferred solution of the numerical simulation method considering nitrogen injection in an aircraft according to the present invention, wherein: the various sensors include an acceleration sensor, a pressure sensor, a temperature sensor and an oxygen concentration sensor;

[0017] The flight data includes vibration data and environmental parameters;

[0018] The environmental parameters include pressure data, temperature data, and oxygen concentration data.

[0019] As a preferred embodiment of the numerical simulation method considering nitrogen injection in an aircraft according to the present invention, wherein: recording the vibration characteristics and real-time state of the recording box and outputting time series data, the specific steps are as follows,

[0020] Combining the vibration data and environmental parameters through a data acquisition device on the aircraft to generate a unified flight data packet;

[0021] Through the data interface configuration in the initial digital twin model, the flight data packet is sent to the digital twin platform in JSON format using wireless transmission;

[0022] The digital twin platform receives and parses the flight data packet, extracts the vibration data as the vibration characteristics of the box, extracts the environmental parameters as the real-time state of the box, organizes them in chronological order, and saves them as time series data.

[0023] As a preferred embodiment of the numerical simulation method considering nitrogen injection in an aircraft according to the present invention, wherein: updating the digital twin model and coupling the vibration effect to generate a flow field change and outputting a real-time simulation model reflecting the flight state, the specific steps are as follows,

[0024] Loading the initial digital twin model and importing the time series data;

[0025] Reading the environmental parameters from the time series data and mapping them to the aircraft physical field configuration file of the initial digital twin model, and saving them as a new aircraft physical field configuration file;

[0026] Reading the vibration data from the time series data and replacing the initial vibration characteristics, and saving them as a new boundary condition file;

[0027] Performing frequency domain analysis on the vibration data in the time series data using wavelet transform, setting the decomposition level to three layers, and separating different frequency vibration components;

[0028] Combining the new aircraft physical field configuration file, the new boundary condition file, and the spatial segmentation in the grid file to simulate the dynamic influence of the vibration characteristics on the nitrogen gas flow field;

[0029] Integrating the initial digital twin model, the new aircraft physical field configuration file, the new boundary condition file, and the real-time flow field data in ANSYS Fluent to output a real-time simulation model of the flight state.

[0030] As a preferred embodiment of the numerical simulation method for aircraft nitrogen injection according to the present invention, wherein: simulating the velocity and concentration distribution of nitrogen injection, analyzing the vibration influence, and outputting real-time flow field data, the specific steps are as follows:

[0031] Load the real-time simulation model, select the injection point at the top center, and confirm the initial flow rate, pressure, and temperature values of nitrogen injection;

[0032] Divide nitrogen and oxygen into multiple components, start the simulation in ANSYS Fluent, simulate the diffusion process of nitrogen from the injection point at the top center into the box body, and obtain real-time flow field data;

[0033] Load the real-time flow field data, and determine whether the nitrogen injection is reasonable according to the flow direction and velocity at the top injection point and the spatial changes in the box body;

[0034] If any abnormality is found, re-run the simulation until it is stable;

[0035] If there is no abnormality, save the checked real-time flow field data.

[0036] As a preferred embodiment of the numerical simulation method for aircraft nitrogen injection according to the present invention, wherein: generating three-dimensional visualization graphics through a visualization tool, the specific steps are as follows:

[0037] Log in to the digital twin platform and import the real-time flow field data;

[0038] Open the visualization tool, set the visualization parameters, and load the real-time flow field data into the visualization tool;

[0039] Generate a vector diagram according to the velocity distribution in the real-time flow field data, and generate a volume view according to the concentration distribution in the real-time flow field data;

[0040] Render the vector diagram and the volume view through the rendering function to generate three-dimensional visualization graphics, and display the velocity distribution and concentration distribution of the real-time flow field of nitrogen injection in the box body.

[0041] As a preferred embodiment of the numerical simulation method for aircraft nitrogen injection according to the present invention, wherein: calculating the nitrogen injection efficiency index and adding it to the three-dimensional visualization graphics, rendering and packaging the three-dimensional visualization graphics and transmitting them to the control center to display the distribution state and the nitrogen injection efficiency index, the specific steps are as follows:

[0042] Utilize the data analysis of the digital twin platform to analyze the velocity distribution and concentration distribution of the real-time flow field, and calculate the nitrogen injection efficiency index;

[0043] Add the nitrogen injection performance index into the 3D visualization graph, turn on the video rendering, set the rendering parameters, convert the 3D visualization graph into a real-time video stream, and display the dynamic changes of nitrogen injection;

[0044] In the page design, generate an interactive interface based on the real-time video stream;

[0045] Package the real-time video stream and the nitrogen injection performance index, and send them to the control center through the Ethernet interface.

[0046] In a second aspect, the present invention provides a computer device, including a memory and a processor, where the memory stores a computer program, and: when the computer program is executed by the processor, any step of the numerical simulation method for considering aircraft nitrogen injection as described in the first aspect of the present invention is implemented.

[0047] In a third aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored, and: when the computer program is executed by the processor, any step of the numerical simulation method for considering aircraft nitrogen injection as described in the first aspect of the present invention is implemented.

[0048] The beneficial effects of the present invention are as follows: The present invention enhances the efficiency of aircraft nitrogen injection numerical simulation through a digital twin platform. By constructing an initial digital twin model using computer-aided design software and computational fluid dynamics tools, it realizes the accurate digital mapping of the physical structure of the fuel tank, providing a high-fidelity basis for simulation. It receives and analyzes the flight data packets collected by aircraft sensors, integrates vibration and environmental parameters into time-series data, ensures a high degree of synchronization between simulation inputs and actual flight states, updates the digital twin model and couples the vibration effect, and generates a real-time simulation model reflecting dynamic flight conditions, breaking through the limitations of traditional static simulations. Description of the Drawings

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0050] Figure 1 It is a flowchart of the numerical simulation method for considering aircraft nitrogen injection in Embodiment 1.

[0051] Figure 2 It is a flowchart of generating a 3D visualization graph in Embodiment 1. Detailed Embodiments

[0052] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following detailed description of the specific embodiments of the present invention will be given in conjunction with the accompanying drawings of the specification.

[0053] In the following description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention may be practiced in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0054] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that exclude each other.

[0055] Example 1, referring to Figure 1 and Figure 2 , is the first embodiment of the present invention. This embodiment provides a numerical simulation method considering aircraft nitrogen injection, including the following steps:

[0056] S1. Construct an initial digital twin model of the aircraft fuel tank through computer-aided design software and computational fluid dynamics tools.

[0057] Furthermore, open the design drawing of the aircraft fuel tank through SolidWorks, draw a rectangular box and partitions, and set the center of the top as the nitrogen injection point, and output a three-dimensional geometric model;

[0058] Specifically, the operator starts the computer-aided design software (SolidWorks), clicks on the "File" menu in the software main interface, selects the "Open" option, and loads the design drawing file of the aircraft fuel tank (usually in DXF or DWG format);

[0059] Use the "Part" function of the computer-aided design software (SolidWorks) to create a three-dimensional geometric model: click on the "Sketch" tool to draw the bottom contour of the rectangular box, and set it to the shape of a cuboid; generate the box shell through the "Extrusion" function; then add partitions inside the box, use the "Sketch" tool to draw the partition contour perpendicular to the bottom surface, and then generate the partition entity through "Extrusion". Then add a nitrogen injection point at the center of the top of the box (geometric center), marked as a circular opening;

[0060] Adjust the view angle, and use the "Check Geometry" function to verify whether the box and partitions meet the requirements of the design drawing, and confirm that there is no deviation in the position of the injection point;

[0061] After completion, click on the "File" menu, select the "Save" option, and save the drawn model as a SolidWorks part file (.SLDPRT format) as the 3D geometric model;

[0062] Save the drawn 3D geometric model as a STEP standard format file and import it into ANSYS Fluent;

[0063] Specifically, the operator opens the generated geometric file (.SLDPRT format) in the computer-aided design software (SolidWorks), clicks on the "File" menu, and selects the "Save As" option;

[0064] In the save dialog box, select the STEP format (.STEP), click the "Save" button, convert the 3D geometric model to a STEP standard format file, name it the geometric export file, and ensure compatibility with the computational fluid dynamics tool;

[0065] Start the computational fluid dynamics tool (ANSYS Fluent) software, click on the "File" menu in the main interface, select the "Import" option, browse and load the just-saved geometric export file (.STEP format);

[0066] After the import is completed, check the 3D geometric model in the geometric editing interface of the computational fluid dynamics tool (ANSYS Fluent) to confirm that the positions of the box shell, partition, and injection points are complete and error-free, and avoid geometric loss during the import process;

[0067] Use the unstructured mesh in ANSYS Fluent to spatially divide the partition and rectangular box in the 3D geometric model and save it as a mesh file;

[0068] Specifically, the operator opens the imported 3D geometric model in the computational fluid dynamics tool (ANSYS Fluent), selects the "Mesh" menu, and enters the "Mesh Generation" function;

[0069] In the mesh settings interface, select the unstructured mesh type, click the "Auto Mesh" option, set the mesh density to a medium level, ensure coverage of the box and partition areas, and especially increase the mesh density near the top injection point;

[0070] Click the "Generate" button, and the computational fluid dynamics tool (ANSYS Fluent) automatically divides the box space into irregular small pieces to form a mesh structure. After the division process is completed, click the "Check Mesh" function to confirm that there are no overlapping or missing areas;

[0071] Select the "Save Mesh" option in the "File" menu and save the generated mesh data as a mesh file (.MSH format);

[0072] Open the 3D geometric model, initialize the flow rate, pressure, and temperature of nitrogen injection, and initialize the oxygen concentration distribution in the fuel tank, and output the aircraft physical field configuration file;

[0073] Specifically, the operator opens the imported 3D geometric model in the computational fluid dynamics tool (ANSYS Fluent), clicks on the "Settings" menu, and enters the "Physical Field Settings" interface;

[0074] In the "Boundary Conditions" option, select the top center injection point, input the initial flow rate, pressure, and temperature values of nitrogen injection, set based on aviation field standards (specific values are provided by design requirements), and confirm that the injection point position is correct;

[0075] In the "Materials" option, select the interior space of the box, and set the initial oxygen concentration distribution to a uniform state, covering the entire box area;

[0076] Click the "Save Configuration" button to save these physical field setting data as an aircraft physical field configuration file (.BCF format);

[0077] Add vibration characteristics to the top of the box of the 3D geometric model through the software boundary setting function in ANSYS Fluent, and output the boundary condition file;

[0078] Specifically, the operator opens the imported 3D geometric model again in the computational fluid dynamics tool (ANSYS Fluent), clicks on the "Boundary Conditions" menu, and enters the boundary setting interface;

[0079] Select the top surface of the box, add vibration characteristics in the "Boundary Type" option, set it to a periodic perturbation form, and the vibration direction is perpendicular to the top;

[0080] Click the "Apply" button to load the vibration characteristics to the top boundary, and check whether the settings are correctly displayed on the surface of the 3D geometric model;

[0081] In the "File" menu, select the "Save Boundary Conditions" option to save the vibration characteristics as a boundary condition file (.BCF format);

[0082] Start the digital twin platform, configure the data interface and connect ANSYS Fluent and various sensors on the aircraft as the data receiving channel for the initial simulation, and generate the data interface configuration file;

[0083] Specifically, the operator starts the digital twin platform (Siemens MindSphere) platform, clicks on the "Interface Management" option on the main interface, and selects the "New Data Interface" function;

[0084] On the interface configuration interface, select the wireless transmission mode, input the receiver identifier of the computational fluid dynamics tool (ANSYS Fluent) and the transmitter identifier of the aircraft sensor, and establish a connection channel;

[0085] Click the "Test Connection" button to send a test signal, and confirm that the digital twin platform (Siemens MindSphere) can receive flight data (vibration data and environmental parameters (pressure, temperature, oxygen concentration)), and adjust the settings until the connection is stable;

[0086] Click the "Save" button to save the interface settings as a data interface configuration file (.JSON format);

[0087] Load and integrate the drawn 3D geometric model, mesh file, physical field configuration file, boundary condition file, and data interface configuration file in ANSYS Fluent, simulate the initial flow of nitrogen in the box, generate the initial velocity distribution and concentration distribution, and output the initial digital twin model;

[0088] Specifically, the operator opens the "Model Integration" interface in the computational fluid dynamics tool (ANSYS Fluent), and sequentially loads the 3D geometric model (STEP format), mesh file (.MSH format), aircraft physical field configuration file (.BCF format), boundary condition file (.BCF format), and data interface configuration file (.JSON format);

[0089] Click the "Check Integration" button to confirm that the mesh covers the geometry, the physical field parameters and vibration characteristics are correctly applied, and the interface configuration shows the connection status;

[0090] In the "Solve" menu, select the "Static Simulation" option, click the "Run" button, and the computational fluid dynamics tool (ANSYS Fluent) simulates the initial flow of nitrogen in the box according to the mesh file, physical field configuration file, and boundary condition file, and generates velocity distribution data (describing the nitrogen flow direction) and concentration distribution data (showing the nitrogen and oxygen distribution);

[0091] After the simulation is completed, check the result interface, confirm whether the distribution of nitrogen from the top injection point is reasonable, save it as an initial flow field data file (.DAT format), and name it the initial flow field export file;

[0092] Click the "Save Project" button to package all the integrated files (3D geometric model (STEP format), mesh file (.MSH format), aircraft physical field configuration file (.BCF format), boundary condition file (.BCF format), and data interface configuration file (.JSON format)) and the initial flow field data file into an initial digital twin model (.CAS format);

[0093] It should be noted that by using computer-aided design software and computational fluid dynamics tools to construct the initial digital twin model, high-precision digital mapping of the aircraft fuel tank is achieved. The three-dimensional geometric model is accurately drawn by SolidWorks and unstructured grids are generated in ANSYS Fluent, ensuring fine spatial segmentation and conforming to the actual structure. The nitrogen injection parameters and vibration characteristics are initialized, the sensor data interfaces are integrated, the preliminary flow is simulated, and the initial digital twin model is output, laying a foundation for subsequent real-time simulation.

[0094] S2. Use various sensors installed on the aircraft to collect flight data, record the vibration characteristics and real-time status of the tank body, and output time series data.

[0095] Furthermore, the flight data includes vibration data and environmental parameters;

[0096] The environmental parameters include pressure data, temperature data, and oxygen concentration data;

[0097] Specifically, activate the acceleration sensor (ADXL345) through the data acquisition device (Raspberry Pi 4), which is installed at the center of the top of the fuel tank and is consistent with the injection point of the three-dimensional geometric model (.SLDPRT and.STEP formats);

[0098] The acceleration sensor measures the vibration data (speed and amplitude) of the top of the tank body in different flight phases in real time, with the direction perpendicular to the top and consistent with the boundary condition file (.BCF format);

[0099] Activate the environmental sensor group through the data acquisition device, including a pressure sensor (BMP280), a temperature sensor (DS18B20), and an oxygen concentration sensor (KE-25), which are installed on the inner wall of the fuel tank;

[0100] The environmental sensor group measures the pressure data, temperature data, and oxygen concentration data inside the tank body in real time, generates environmental parameters, and reflects the real-time status of the tank body;

[0101] Merge the vibration data and environmental parameters through the data acquisition device on the aircraft to generate a unified flight data packet. Define the transmission protocol through the data interface configuration file in the initial digital twin model, set the transmission frequency at a fixed interval, and send the flight data packet in JSON format to the digital twin platform through wireless transmission;

[0102] Specifically, start the "data integration" function in the data acquisition device on the aircraft and open the data input interface;

[0103] Receive raw data collected in real time from multiple sensors: vibration data (speed and amplitude) provided by an acceleration sensor (ADXL345), and environmental parameters (pressure data, temperature data, oxygen concentration data) provided by a pressure sensor (BMP280), a temperature sensor (DS18B20), and an oxygen concentration sensor (KE-25);

[0104] The data acquisition device integrates these raw data into a unified data set, ensuring that each set of data contains a time point, vibration speed, vibration amplitude, pressure value, temperature value, and oxygen concentration value, and generates unified flight data;

[0105] Open the "Transfer Settings" interface in the data acquisition device, select the "Frequency Configuration" option, and set the transfer frequency to a fixed interval (e.g., once per second) to ensure data real-time;

[0106] The data acquisition device converts the unified flight data into the standard JSON format. Each data packet contains time markers (such as "timestamp"), vibration speed (such as "frequency"), vibration amplitude (such as "amplitude"), pressure value (such as "pressure"), temperature value (such as "temperature"), and oxygen concentration value (such as "oxygen");

[0107] Click the "Pack" button to generate a JSON format data packet, ensuring a clear data structure for subsequent parsing;

[0108] Activate the "Wireless Transmission" function in the data acquisition device, and use the data interface configuration file (.JSON format) included in the initial digital twin model to define the transmission protocol (such as Wi-Fi);

[0109] The data acquisition device sends the JSON format data packet (unified flight data) to the digital twin platform (Siemens MindSphere) through a wireless channel. The data acquisition device monitors the sending status in real time to ensure that each JSON format data packet is sent at a fixed interval (e.g., once per second). Each data packet contains a time marker, vibration speed, vibration amplitude, pressure value, temperature value, and oxygen concentration value;

[0110] If the wireless signal is interrupted, the data acquisition device caches the JSON format data packet (unified flight data) and reissues it after the signal is restored to ensure that the JSON format data packet (unified flight data) reaches the digital twin platform (Siemens MindSphere) at a fixed interval;

[0111] The digital twin platform receives and loads flight data packets, parses the flight data packets, extracts vibration data as the vibration characteristics of the box body, extracts environmental parameters as the real-time state of the box body, and organizes them in chronological order and saves them as time series data;

[0112] Specifically, log in to the digital twin platform (Siemens MindSphere), click the "Data Management" option on the main interface, select "Load Interface Configuration File", and import the JSON format data packet (unified flight data);

[0113] Start the "Real-time Reception" function. The digital twin platform (Siemens MindSphere) receives the transmitted JSON format data packet (unified flight data), loads data processing, and confirms that each data packet contains a time stamp and complete data fields (vibration speed, amplitude, pressure, temperature, oxygen concentration);

[0114] Check the reception status to ensure that the JSON format data packet (unified flight data) arrives continuously in chronological order without interruption or repetition;

[0115] Open the "Data Parsing" function in the digital twin platform (Siemens MindSphere), select the loaded JSON format data packet (unified flight data), and start the parsing program;

[0116] The digital twin platform (Siemens MindSphere) extracts vibration data (speed and amplitude) from the JSON format data packet, defines it as the vibration characteristics of the box body, reflecting the dynamic behavior of the box body during flight; extracts environmental parameters (pressure data, temperature data, oxygen concentration data), defines it as the real-time state of the box body, reflecting the environmental conditions inside the box body;

[0117] Check the extraction results to ensure that the vibration characteristics and real-time state are consistent with the data packet content, without missing or incorrect data fields;

[0118] Open the "Data Organization" function in the digital twin platform (Siemens MindSphere), sort the extracted vibration characteristics and real-time state according to the time stamp to form continuous time series data;

[0119] Each time series data contains a time point, vibration speed, vibration amplitude, pressure value, temperature value, and oxygen concentration value, ensuring that the changes of the box body over time are recorded;

[0120] Click the "Save" button to save the organized time series data as a time series data file (.CSV format), named the real-time data export file, and store it in the digital twin platform (Siemens MindSphere) database.

[0121] It should be noted that by using a variety of sensors to collect flight data and output time series data, the dynamics of nitrogen injection simulation is improved. Through the acceleration and environmental sensors installed in the aircraft fuel tank, the vibration characteristics and state parameters are captured in real time. The data acquisition device integrates and generates a flight data packet in JSON format, which is wirelessly transmitted to the digital twin platform and parsed into a time series, reflecting the real behavior of the box during flight, realizing the efficient acquisition and transmission of sensor data. Compared with traditional offline data, it ensures the real-time and synchronization of the simulation, and enhances the accuracy of nitrogen injection effect prediction.

[0122] S3. Update the digital twin model and couple the vibration effect to generate the flow field change, and output a real-time simulation model reflecting the flight state.

[0123] Furthermore, load the initial digital twin model and import the time series data;

[0124] Specifically, start the computational fluid dynamics tool (ANSYS Fluent), load the initial digital twin model file, which includes a three-dimensional geometric model, a mesh file, an initial aircraft physical field configuration file, an initial boundary condition file, and a data interface configuration file;

[0125] Through the model editing interface of the computational fluid dynamics tool (ANSYS Fluent), verify that the initial digital twin model is successfully loaded, confirm that the positions of the box shell, partition, and top center injection point in the three-dimensional geometric model are correct, and the mesh file covers the space completely;

[0126] In the computational fluid dynamics tool (ANSYS Fluent), select the "Data Import" function and load the time series data file (.CSV format), which includes vibration data (frequency and amplitude) and environmental parameters (pressure data, temperature data, oxygen concentration data);

[0127] Check whether the time series data file is correctly imported and confirm that the data fields (time stamp, vibration speed, vibration amplitude, pressure, temperature, oxygen concentration) are complete;

[0128] Read the environmental parameters from the time series data, map them to the aircraft physical field configuration file of the initial digital twin model, update the pressure, temperature, and oxygen concentration distributions in the box, and save them as a new aircraft physical field configuration file;

[0129] Specifically, in the computational fluid dynamics tool (ANSYS Fluent), open the "Physical Field Settings" interface, select the initial aircraft physical field configuration file (.BCF format) in the initial digital twin model, and enter the parameter editing mode;

[0130] Read environmental parameters from the imported time - series data file (in.CSV format), including pressure data (corresponding to the air pressure inside the box), temperature data (corresponding to the air temperature inside the box), and oxygen concentration data (corresponding to the oxygen distribution inside the box);

[0131] Map the read environmental parameters to the initial aircraft physical field configuration file, update the pressure, temperature, and oxygen concentration distributions inside the box, and keep the initial flow rate, pressure, and temperature values of nitrogen injection unchanged;

[0132] Click the "Apply" button to load the updated environmental parameters into the initial digital twin model and check whether the internal state of the box reflects real - time data (such as changes in pressure, temperature, and oxygen concentration);

[0133] Select the "Save Configuration" option in the "File" menu and save the updated physical field parameters as a new aircraft physical field configuration file (in.BCF format);

[0134] Read vibration data from the time - series data, convert the vibration data into a periodic data format, replace the initial vibration characteristics, update the boundary conditions, and save them as a new boundary condition file;

[0135] Specifically, open the "Boundary Conditions" setting interface in the computational fluid dynamics tool (ANSYS Fluent), select the initial boundary condition file (in.BCF format) in the initial digital twin model, and locate to the top boundary of the box;

[0136] Read vibration data from the imported time - series data file (in.CSV format), including speed (frequency) and amplitude, and extract them as the real - time vibration characteristics of the box;

[0137] Convert the vibration data into a periodic data format (such as a sine - wave form), which is consistent with the direction (perpendicular to the top) defined in the initial boundary condition file, and use the "User - Defined Function" (UDF) tool of the computational fluid dynamics tool (ANSYS Fluent) to load the real - time vibration characteristics and replace the initial vibration conditions;

[0138] Click the "Apply" button to update the boundary conditions at the top of the box and check whether the vibration characteristics are correctly displayed on the top surface;

[0139] Select the "Save Boundary Conditions" option in the "File" menu and save the updated boundary conditions as a new boundary condition file (in.BCF format);

[0140] Perform frequency - domain analysis on the vibration data in the time - series data using wavelet transform, set the decomposition level to three layers, and separate different - frequency vibration components;

[0141] The first layer decomposes the input vibration data, extracts the low-frequency components of the vibration data through a low-pass filter, and generates the first-layer approximation coefficient A1;

[0142] Extracts the high-frequency components of the vibration data through a high-pass filter and generates the first-layer detail coefficient D1;

[0143] The second-layer decomposition extracts the low-frequency components in A1 through a low-pass filter and generates the second-layer approximation coefficient A2;

[0144] Extracts the high-frequency components in A1 through a high-pass filter and generates the second-layer detail coefficient D2;

[0145] The third-layer decomposition extracts the low-frequency components in A2 through a low-pass filter and generates the third-layer approximation coefficient A3;

[0146] Extracts the high-frequency components in A2 through a high-pass filter and generates the third-layer detail coefficient D3;

[0147] Maps the approximation coefficient A3 of the third-layer decomposition as the low-frequency vibration component to the new boundary condition file to update the vibration characteristics;

[0148] Combines the D1, D2, and D3 detail coefficients of the first, second, and third-layer decompositions through inverse wavelet transform into the high-frequency vibration component and maps it to the new aircraft physical field configuration file to update the nitrogen gas flow field (high-frequency perturbations in the nitrogen gas flow field);

[0149] It should be noted that the low-frequency vibration component A3 is the lowest-frequency approximation coefficient after three-layer decomposition, representing the low-frequency trend of the vibration data, suitable for mapping to the new boundary condition file to update the vibration characteristics (low-frequency structural response at the top of the box), where A1 and A2 will introduce high-frequency components and destroy the purity of the low-frequency component;

[0150] The high-frequency vibration component is combined through the inverse wavelet transform of D1 + D2 + D3, where D1, D2, and D3 are all high-frequency detail coefficients generated by three-layer decomposition, covering all high-frequency ranges of the vibration data. After being combined through the inverse wavelet transform, the complete high-frequency vibration component is restored, suitable for mapping to the new aircraft physical field configuration file to update the nitrogen gas flow field (high-frequency perturbations in the flow field).

[0151] Combines the spatial segmentation in the new aircraft physical field configuration file, the new boundary condition file, and the grid file to simulate the dynamic impact of the vibration characteristics on the nitrogen gas flow field and generate initial real-time flow field data;

[0152] Specifically, in the computational fluid dynamics tool (ANSYS Fluent), open the "Solve" menu, select the "Transient Simulation" option, set the time step to be consistent with the transmission frequency of the time series data (such as once per second) to ensure that the simulation is synchronized with the real-time data;

[0153] Load the new aircraft physical field configuration file (in.BCF format) and the new boundary condition file (in.BCF format). Combine the spatial division defined by the mesh file (in.MSH format) in the initial digital twin model. Click the "Initialize" button, use the initial flow field data as the starting point, start the computational fluid dynamics calculation, and simulate the dynamic impact of the real-time vibration characteristics on the nitrogen gas flow field (including velocity distribution, concentration distribution, and real-time performance).

[0154] Among them, the velocity distribution is the periodic fluctuation of the nitrogen gas flow changed by the vibration speed (frequency), and the amplitude affects the flow intensity. For example, when there is no vibration, the nitrogen gas flows smoothly downward from the top injection point, and the velocity distribution is uniform. When there is vibration, the top vibration introduces periodic disturbances, and the velocity distribution fluctuates. For example, high-frequency vibration may cause local eddies to form near the top, and large-amplitude vibration may enhance the downward flow, affecting the overall flow field of the box body.

[0155] The concentration distribution is the vibration disturbance of the nitrogen gas diffusion path. High-frequency vibration accelerates mixing, and large-amplitude vibration will cause local non-uniformity of concentration, which is dynamically adjusted over time. For example, when there is no vibration, the nitrogen gas is injected from the top, and the concentration distribution gradually becomes uniform with diffusion. When there is vibration, the vibration disturbs the diffusion path, and the speed change affects the mixing rate, and the amplitude change affects the disturbance range. For example, high-frequency vibration accelerates the mixing of nitrogen gas and oxygen, and large-amplitude vibration may cause a short-term concentration aggregation at the top.

[0156] The real-time performance is that the vibration characteristics change with the flight phases (takeoff, cruise), and the flow field response is also dynamically adjusted accordingly, reflecting the real flight conditions.

[0157] In the computational fluid dynamics tool (ANSYS Fluent), click the "Calculate" button, run a certain number of iterations (for example, 100 times), monitor the computational stability (residual convergence), and generate real-time flow field data, including the velocity distribution (dynamic changes of the nitrogen gas flow) and the concentration distribution (dynamic distribution of nitrogen gas and oxygen).

[0158] Click the "Save Results" button to save the real-time flow field data as a real-time flow field data file.

[0159] Integrate the initial digital twin model, the new aircraft physical field configuration file, the new boundary condition file, and the real-time flow field data in ANSYS Fluent to output a real-time simulation model of the flight state.

[0160] In the computational fluid dynamics tool (ANSYS Fluent), open the "Model Integration" interface and load the initial digital twin model, the new aircraft physical field configuration file, the new boundary condition file, and the real-time flow field data file.

[0161] Click the "Check Integration" button to match the 3D geometric model, mesh file with the new aircraft physical field configuration file and real-time flow field data file, ensuring that the vibration characteristics and real-time status are correctly applied;

[0162] Select the "Save Project" option in the "File" menu and save it as a real-time simulation model;

[0163] It should be noted that by updating the digital twin model and coupling the vibration effect, a real-time simulation model reflecting the flight state is output, significantly improving the dynamics of nitrogen injection simulation. By loading the digital twin model and importing time series data, updating the physical field and boundary conditions, ANSYS Fluent simulates the dynamic impact of vibration on the flow field, outputs real-time flow field data, and integrates to generate a real-time simulation model, achieving an accurate dynamic simulation of nitrogen injection behavior under flight conditions. Compared with traditional static methods, the response ability to vibration disturbances is enhanced.

[0164] S4. Simulate the velocity and concentration distribution of nitrogen injection, analyze the vibration effect, and output real-time flow field data.

[0165] Furthermore, load the real-time simulation model of the flight state;

[0166] Specifically, start the computational fluid dynamics tool (ANSYS Fluent), click the "File" menu on the main interface, and select the "Open Project" option;

[0167] Browse the file path, find the real-time simulation model of the flight state, click the "Open" button to load it. The real-time simulation model of the flight state includes a 3D geometric model, mesh file, new aircraft physical field configuration file (including real-time pressure, temperature, oxygen concentration), new boundary condition file (including real-time vibration characteristics), and real-time flow field data file;

[0168] In the model editing interface of the computational fluid dynamics tool, confirm that the real-time simulation model of the flight state is successfully loaded, check whether the positions of the box shell, partition board, and top center injection point in the 3D geometric model are correct, the mesh file covers the entire space completely, and the real-time flow field data reflects the vibration effect;

[0169] Select the top center injection point and confirm the initial flow rate, pressure, and temperature values of nitrogen injection;

[0170] Specifically, open the "Physical Field Settings" interface in the computational fluid dynamics tool (ANSYS Fluent), select the new aircraft physical field configuration file in the loaded real-time simulation model of the flight state, and enter the parameter editing mode;

[0171] In the "Boundary Conditions" option, select the top center injection point (consistent with the position in the 3D geometric model), and confirm the initial flow rate, pressure, and temperature values of nitrogen injection, which are defined by the initial digital twin model;

[0172] Check whether the parameters of the top center injection point are coordinated with the real-time environmental parameters (pressure, temperature, oxygen concentration). Click the "Apply" button to load the initial nitrogen injection parameters into the 3D geometric model and confirm that the top center injection point is set correctly;

[0173] Divide nitrogen and oxygen into multiple components, start the simulation function in ANSYS Fluent, and combine the new aircraft physical field configuration file, the new boundary condition file, and the mesh file to simulate the diffusion process of nitrogen from the top center injection point into the box interior to obtain real-time flow field data;

[0174] Specifically, in the computational fluid dynamics tool (ANSYS Fluent), open the "Materials" menu, select the "Multicomponent Model" option, define nitrogen and oxygen as the main components, and enable the multicomponent simulation function to ensure the mixing process of nitrogen with oxygen in the box after nitrogen injection;

[0175] Return to the "Solve" menu, select the "Transient Simulation" option, and set the time step to be consistent with the transmission frequency of the time series data file (such as once per second) to ensure that the simulation is synchronized with the real-time data;

[0176] Load the real-time simulation model, and combine the new aircraft physical field configuration file (including real-time pressure, temperature, oxygen concentration), the new boundary condition file (including real-time vibration characteristics), and the spatial segmentation defined by the mesh file;

[0177] Click the "Initialize" button, use the real-time flow field data file as the starting point, start the fluid mechanics calculation, and simulate the diffusion process of nitrogen from the top center injection point into the box interior;

[0178] Continue to run the transient simulation in the computational fluid dynamics tool (ANSYS Fluent), and calculate the flow field changes after nitrogen injection based on the space segmented by the mesh file and the real-time vibration characteristics of the new boundary condition file;

[0179] The simulation process generates real-time flow field data, including velocity distribution (describing the flow direction and velocity of nitrogen, affected by the speed and amplitude of vibration, such as high-frequency vibration causing local eddies) and concentration distribution (describing the spatial variation of nitrogen and oxygen in the box, affected by the diffusion path of vibration disturbance);

[0180] Run several iterations (for example, 100 times), monitor the calculation stability (residual convergence), and ensure that the simulation results reflect the dynamic impact of vibration characteristics on the nitrogen flow field;

[0181] Click the "Save Results" button to save the real-time flow field data as a real-time flow field data file;

[0182] Load the real-time flow field data, check the velocity distribution and concentration distribution of nitrogen injection, and determine whether the nitrogen injection is reasonable according to the flow direction and velocity of the top injection point and the spatial changes in the box;

[0183] Specifically, open the "Result View" interface in the computational fluid dynamics tool (ANSYS Fluent), load the real-time flow field data file, and display the real-time flow field and concentration distribution of nitrogen injection;

[0184] Check the velocity distribution and confirm whether the flow direction and velocity of nitrogen from the top injection point are reasonable (such as whether the fluctuations under vibration effects meet expectations);

[0185] Check the concentration distribution and confirm whether the spatial changes of nitrogen and oxygen in the box are reasonable (such as high concentration at the top and uniform diffusion at the bottom);

[0186] If any abnormality is found (such as abnormal fluctuations in velocity distribution or uneven concentration distribution), return to the "Solve" menu and re-run the simulation until it is stable;

[0187] If there is no abnormality, save the checked real-time flow field data;

[0188] It should be noted that by real-time collecting the vibration data (frequency and amplitude) and environmental parameters (pressure, temperature, oxygen concentration) of the aircraft fuel tank, using ANSYS Fluent and wavelet transform to accurately simulate the influence of vibration on the nitrogen flow field, after integrating the acceleration sensor and environmental sensor data, time series data is generated to update the digital twin model, optimize the nitrogen injection efficiency, enhance the safety of the box and flight stability, dynamically simulate the velocity and concentration distribution, reveal the periodic influence of vibration disturbance on the flow field, improve the real-time monitoring accuracy, and reduce potential risks.

[0189] S5. Generate three-dimensional visualization graphics through a visualization tool, calculate the nitrogen injection effectiveness index and add it to the three-dimensional visualization graphics, render and package the three-dimensional visualization graphics and transmit them to the control center to display the distribution status and nitrogen injection effectiveness index.

[0190] Furthermore, log in to the digital twin platform and import the real-time flow field data;

[0191] Specifically, open a browser, enter the login address of the digital twin platform (Siemens MindSphere), enter the username and password, and click the "Login" button to enter the main interface;

[0192] On the main interface, click the "Data Management" menu, select the "Import Data" option, and a file selection window will pop up;

[0193] Browse the file path, find the real-time flow field data file, click the "Open" button to import it, and confirm the file name (such as "Real-time Flow Field Export File");

[0194] After showing "Data Import Successful", check the imported data fields to ensure that they include velocity distribution and concentration distribution;

[0195] Open the visualization tool, set the visualization parameters, and load the real-time flow field data into the visualization tool;

[0196] Specifically, click the "Visualization Tool" icon on the main interface of the digital twin platform (Siemens MindSphere) to start the built-in visualization tool;

[0197] On the visualization tool interface, click the "Set Parameters" button to open the parameter configuration window and set the visualization parameters;

[0198] The velocity distribution is as follows: Select "Vector Display", and set the arrow size ratio (such as 0.1) and color range (such as low speed in blue to high speed in red);

[0199] The concentration distribution is as follows: Select "Volume Rendering", and set the concentration color gradient (such as low concentration in blue to high concentration in red);

[0200] Click the "Load Data" option, select the real-time flow field data file, click the "Confirm" button, and load the data (velocity distribution and concentration distribution) into the visualization tool;

[0201] Check the loading status to ensure that the data is displayed correctly (such as the velocity vectors and concentration distribution preview are visible);

[0202] Generate a vector map based on the velocity distribution in the real-time flow field data, and generate a volume view based on the concentration distribution in the real-time flow field data;

[0203] Specifically, click the "Generate Graph" menu in the visualization tool, select the "Vector Map" option, and generate a 3D vector map based on the velocity distribution data in the real-time flow field data to show the nitrogen flow direction and velocity magnitude;

[0204] Click the "Volume View" option, and generate a 3D volume view based on the concentration distribution data in the real-time flow field data to show the spatial distribution of nitrogen and oxygen in the box;

[0205] Check the generated vector map and volume view to ensure that the arrow direction of the vector map is consistent with the velocity distribution, the color reflects the velocity change, and the color gradient of the volume view matches the concentration distribution (such as high concentration at the top is red);

[0206] Render the vector graph and volume view through the rendering function to generate 3D visualization graphics, and display the velocity distribution and concentration distribution of the real-time flow field of nitrogen injection in the box;

[0207] Specifically, click the "Render Settings" button in the visualization tool to set the rendering parameters. The resolution is 1920x1080 (high definition), the lighting mode is to enable ambient light and parallel light to enhance the three-dimensional sense, and the viewing angle is the default top-down view of the box top, which can be adjusted manually;

[0208] Click the "Render" button to render the vector graph and volume view to generate 3D visualization graphics, and display the real-time flow field (velocity distribution and concentration distribution) of nitrogen injection in the box;

[0209] Utilize the data analysis of the digital twin platform to analyze the velocity distribution and concentration distribution of the real-time flow field, and calculate the nitrogen injection efficiency index;

[0210] The average velocity expression is:

[0211]

[0212] The average nitrogen concentration expression is:

[0213]

[0214] The nitrogen concentration standard deviation expression is:

[0215]

[0216] The average oxygen concentration expression is:

[0217]

[0218] The comprehensive efficiency expression is:

[0219]

[0220] Among them, is the average velocity, representing the average velocity magnitude of nitrogen flow in the box, with the unit of meters per second (m / s). It is the average of the velocities of all grid points and is used to measure the flow intensity of nitrogen injection. N is the total number of grid points, representing the number of points for spatial discretization in the box, without a unit, and is defined by the grid file. For example, if the box is divided into 1 million grid points, then N = 1,000,000, v i is the velocity magnitude of the i-th grid point, with the unit of meters per second (m / s). It is a single value of the velocity distribution in the real-time flow field data, representing the flow velocity of nitrogen at this point, and is the vector modulus (magnitude), |v i| is the absolute value (modulus) of velocity, ensuring that all velocity values in the calculation are positive to avoid direction cancellation, is the average factor, dividing the sum by the number of grid points to obtain the average value, is the average value of nitrogen concentration, representing the average nitrogen concentration in the chamber, in percentage (%), which is the average of nitrogen concentrations at all grid points, μ is the average of nitrogen concentrations at all grid points in the chamber, is the nitrogen concentration at the i-th grid point, in percentage (%), which is a single value of the concentration distribution in the real-time flow field data, representing the proportion of nitrogen in the total gas at that point (e.g., 95%), C is the nitrogen concentration at a certain point in the chamber, σ N2 is the standard deviation of nitrogen concentration, in percentage (%), which is a statistical index measuring the dispersion degree of nitrogen concentration distribution. The larger the value, the more uneven the distribution. σ is the standard deviation, (C N2,i - μ N2 ) is the deviation between the nitrogen concentration at the i-th grid point and the average value, in percentage (%), μ O2 is the average value of oxygen concentration, representing the average oxygen concentration in the chamber, in percentage (%), which is the average of oxygen concentrations at all grid points, reflecting the nitrogen replacement effect, O is oxygen, C O2,i is the oxygen concentration at the i-th grid point, in percentage (%), which is a single value of the concentration distribution in the real-time flow field data, representing the proportion of oxygen in the total gas at that point (e.g., 5%). E is the nitrogen injection efficiency index, dimensionless, which is a comprehensive value measuring the flow efficiency and distribution effect of nitrogen injection. The larger the value, the better the effect;

[0221] Define an efficiency threshold for E;

[0222] For example: E > 10 represents excellent efficiency (strong flow, high uniformity, low oxygen);

[0223] 5 < E ≤ 10 represents medium efficiency;

[0224] E ≤ 5 represents poor efficiency;

[0225] The specific efficiency threshold should be defined according to the actual scenario;

[0226] Add the calculated nitrogen injection efficiency index into the 3D visualization graph to generate the 3D visualization graph result with the index;

[0227] Turn on video rendering, set the rendering parameters, and convert the 3D visualization graph result into a real-time video stream to display the dynamic changes of nitrogen injection;

[0228] Specifically, click on the "Video Rendering" menu in the visualization tool, select the "Create Video Stream" option, and open the rendering settings window;

[0229] Set rendering parameters:

[0230] Frame rate: 10 frames per second (smooth dynamic display);

[0231] Format: MP4 (standard video format);

[0232] Duration: Automatically adjusted according to time series data (e.g., 30 seconds);

[0233] Click the "Render" button to convert the three-dimensional visualization graph with indicators into a real-time video stream, showing the dynamic change process of nitrogen injection;

[0234] Check the video preview to ensure that the dynamic effects of velocity distribution and concentration distribution are accurate and the indicator text is displayed synchronously;

[0235] In the page design, generate an interactive interface based on the real-time video stream and save it as an interactive visualization file;

[0236] Specifically, click the "Page Design" menu, select the "Create Interactive Interface" option, and open the design window;

[0237] Drag the real-time video stream into the interface design area and set the playback controls (such as play, pause, fast forward);

[0238] Add interactive functions:

[0239] Zoom: Enable mouse wheel zooming to support viewing of local parts of the box;

[0240] Rotation: Enable mouse drag rotation to support multi-angle observation;

[0241] Click the "Save" button to save the interactive interface as an interactive visualization file (format such as.HTML or MindSphere internal format), named such as "Nitrogen Injection Visualization Interface";

[0242] Package the real-time video stream and key indicators (formatted as JSON) and send them to the control center through the Ethernet interface;

[0243] It should be noted that the real-time video stream (MP4 format) is a dynamic display generated by converting the three-dimensional visualization graph with indicators;

[0244] The nitrogen injection efficiency index (E) is a key index calculated separately and stored in JSON format;

[0245] Combine the real-time video stream and the nitrogen injection efficiency index into a transmission data packet and send it through Ethernet;

[0246] It should be noted that by generating visualization results using real-time flow fields and concentration distributions and transmitting them to the control center, the visualization and decision-making support capabilities for nitrogen injection effects are enhanced. By loading data, generating vector diagrams and volume views, and rendering 3D graphics through a digital twin platform, combined with nitrogen injection performance indicators, a video stream and an interactive interface are output, and the distribution status and key indicators are displayed in real-time transmission, achieving an intuitive presentation and quantitative evaluation of the dynamic process of nitrogen injection. Compared with traditional static displays, the real-time monitoring and analysis capabilities of the control center for the box status are enhanced.

[0247] This embodiment also provides a computer device applicable to the situation of the numerical simulation method considering aircraft nitrogen injection, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the numerical simulation method considering aircraft nitrogen injection proposed in the above embodiment.

[0248] This computer device can be a terminal, which includes a processor, a memory, a communication interface, a display screen, and an input device connected through a system bus. Among them, the processor of this computer device is used to provide computing and control capabilities. The memory of this computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of this computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a carrier network, NFC (Near Field Communication), or other technologies. The display screen of this computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of this computer device can be a touch layer covering the display screen, or a button, a trackball, or a touchpad set on the outer shell of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0249] This embodiment also provides a storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the numerical simulation method for aircraft nitrogen injection as proposed in the above embodiment; the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, abbreviated as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, abbreviated as EEPROM), erasable programmable read-only memory (Erasable Programmable Read Only Memory, abbreviated as EPROM), programmable read-only memory (Programmable Red-Only Memory, abbreviated as PROM), read-only memory (Read-Only Memory, abbreviated as ROM), magnetic memory, flash memory, magnetic disk or optical disc.

[0250] In summary, the present invention enhances the efficiency and application value of aircraft nitrogen injection numerical simulation through a digital twin platform. By constructing an initial digital twin model with computer-aided design software and computational fluid dynamics tools, it realizes the accurate digital mapping of the physical structure of the fuel tank, providing a high-fidelity basis for simulation. It receives and analyzes the flight data packets collected by aircraft sensors, integrates vibration and environmental parameters into time-series data to ensure a high degree of synchronization between simulation input and actual flight conditions, updates the digital twin model and couples the vibration effect, and generates a real-time simulation model reflecting dynamic flight conditions, breaking through the limitations of traditional static simulation.

[0251] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A numerical simulation method considering aircraft nitrogen injection, characterized in that: including, constructing an initial digital twin model of an aircraft fuel tank through computer-aided design software and computational fluid dynamics tools; using a variety of sensors installed on the aircraft to collect flight data, record the vibration characteristics and real-time status of the tank body, and output time series data; updating the digital twin model and coupling the vibration effect to generate a flow field change, and outputting a real-time simulation model reflecting the flight state; simulating the injection speed and concentration distribution of nitrogen, analyzing the vibration influence, and outputting real-time flow field data; generating three-dimensional visualization graphics through a visualization tool, calculating the nitrogen injection efficiency index and adding it to the three-dimensional visualization graphics, rendering and packaging the three-dimensional visualization graphics and transmitting them to the control center to display the distribution state and the nitrogen injection efficiency index.

2. The numerical simulation method considering aircraft nitrogen injection according to claim 1, characterized in that: The specific steps for constructing the initial digital twin model of the aircraft fuel tank through computer-aided design software and computational fluid dynamics tools are as follows: setting the top center as the nitrogen injection point through SolidWorks and outputting a three-dimensional geometric model; importing the three-dimensional geometric model into ANSYS Fluent; using the unstructured grid in ANSYS Fluent to spatially divide the partitions and the tank body in the three-dimensional geometric model and saving it as a grid file; opening the three-dimensional geometric model, initializing the flow rate, pressure and temperature of nitrogen injection and the oxygen concentration distribution of the fuel tank, and outputting an aircraft physical field configuration file; adding vibration characteristics to the top of the tank body of the three-dimensional geometric model through the boundary setting in ANSYS Fluent and outputting a boundary condition file; starting the digital twin platform, configuring the data interface and connecting ANSYS Fluent with a variety of sensors on the aircraft as the data receiving channel for initial simulation; loading and integrating the three-dimensional geometric model, the grid file, the physical field configuration file, the boundary condition file and the data interface configuration file to generate a preliminary velocity distribution and concentration distribution, and outputting the initial digital twin model.

3. The numerical simulation method considering aircraft nitrogen injection according to claim 2, characterized in that: The variety of sensors include acceleration sensors, pressure sensors, temperature sensors and oxygen concentration sensors; The flight data includes vibration data and environmental parameters; The environmental parameters include pressure data, temperature data and oxygen concentration data.

4. The numerical simulation method considering aircraft nitrogen injection according to claim 3, characterized in that: The specific steps for recording the vibration characteristics and real-time status of the tank body and outputting time series data are as follows: merging the vibration data and environmental parameters through the data acquisition device on the aircraft to generate a unified flight data packet; through the data interface configuration in the initial digital twin model, using wireless transmission to send the flight data packet in JSON format to the digital twin platform; The digital twin platform receives and analyzes the flight data packet, extracts the vibration data as the vibration characteristics of the tank body, extracts the environmental parameters as the real-time status of the tank body, organizes them in chronological order, and saves them as time series data.

5. The numerical simulation method considering aircraft nitrogen injection according to claim 4, characterized in that: The specific steps for updating the digital twin model and coupling the vibration effect to generate a flow field change and outputting a real-time simulation model reflecting the flight state are as follows: loading the initial digital twin model and importing the time series data; reading the environmental parameters from the time series data and mapping them to the aircraft physical field configuration file of the initial digital twin model and saving it as a new aircraft physical field configuration file; Read the vibration data from the time - series data, replace the initial vibration characteristics, and save it as a new boundary condition file; Perform frequency - domain analysis on the vibration data in the time - series data using wavelet transform, set the decomposition level to three layers, and separate different - frequency vibration components; Combine the new aircraft physical field configuration file, the new boundary condition file, and the spatial segmentation in the grid file to simulate the dynamic influence of vibration characteristics on the nitrogen gas flow field; Integrate the initial digital twin model, the new aircraft physical field configuration file, the new boundary condition file, and the real - time flow field data in ANSYS Fluent to output a real - time simulation model of the flight state.

6. The numerical simulation method considering aircraft nitrogen injection according to claim 5, characterized in that: The steps for simulating the velocity and concentration distribution of nitrogen injection, analyzing the vibration influence, and outputting the real - time flow field data are as follows: Load the real - time simulation model, select the top - center injection point, and confirm the initial flow rate, pressure, and temperature values of nitrogen injection; Divide nitrogen and oxygen into multiple components, start the simulation in ANSYS Fluent, simulate the diffusion process of nitrogen from the top - center injection point into the box interior, and obtain the real - time flow field data; Load the real - time flow field data, and determine whether the nitrogen injection is reasonable according to the flow direction and velocity at the top injection point and the spatial changes in the box; If an anomaly is found, re - perform the simulation until it is stable; If there is no anomaly, save the checked real - time flow field data.

7. The numerical simulation method considering aircraft nitrogen injection according to claim 6, characterized in that: The steps for generating three - dimensional visualization graphics through a visualization tool are as follows: Log in to the digital twin platform and import the real - time flow field data; Open the visualization tool, set the visualization parameters, and load the real - time flow field data into the visualization tool; Generate a vector diagram according to the velocity distribution in the real - time flow field data, and generate a volume view according to the concentration distribution in the real - time flow field data; Render the vector diagram and the volume view through the rendering function to generate three - dimensional visualization graphics, showing the velocity distribution and concentration distribution of the real - time flow field of nitrogen injection in the box.

8. The numerical simulation method considering aircraft nitrogen injection according to claim 7, characterized in that: The steps for calculating the nitrogen injection efficiency index, adding it to the three - dimensional visualization graphics, rendering and packaging the three - dimensional visualization graphics, and transmitting them to the control center to display the distribution state and the nitrogen injection efficiency index are as follows: Use the data analysis of the digital twin platform to analyze the velocity distribution and concentration distribution of the real - time flow field, and calculate the nitrogen injection efficiency index; Add the nitrogen injection efficiency index to the three - dimensional visualization graphics, turn on the video rendering, set the rendering parameters, and convert the three - dimensional visualization graphics into a real - time video stream to show the dynamic changes of nitrogen injection; In the page design, generate an interactive interface based on the real - time video stream; Package and send the real - time video stream and the nitrogen injection efficiency index to the control center.

9. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the numerical simulation method for aircraft nitrogen injection according to any one of claims 1 - 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the numerical simulation method for aircraft nitrogen injection according to any one of claims 1 - 8.

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