A numerical simulation method considering aircraft nitrogen injection

Abstract

This invention discloses a numerical simulation method considering aircraft nitrogen injection, relating to the field of digital twin technology. The method includes: constructing an initial digital twin model of the aircraft fuel tank using computer-aided design software and computational fluid dynamics tools; collecting flight data using various sensors installed on the aircraft, recording the tank's vibration characteristics and real-time status, and outputting time-series data; updating the digital twin model and coupling vibration effects to generate flow field changes, outputting a real-time simulation model reflecting the flight status; simulating the velocity and concentration distribution of nitrogen injection, analyzing the impact of vibration, and outputting real-time flow field data; generating a three-dimensional visualization using visualization tools, calculating nitrogen injection efficiency indicators and adding them to the three-dimensional visualization, rendering and packaging the three-dimensional visualization, and transmitting it to the control center to display the distribution status and nitrogen injection efficiency indicators. This invention enhances the efficiency of numerical simulation of aircraft nitrogen injection through a digital twin platform.

Description

Technical Field

[0001] This invention relates to the field of digital twin technology, and in particular to a numerical simulation method considering nitrogen injection into an aircraft. Background Technology

[0002] With the development of the aviation industry, nitrogen injection technology, as an effective inerting method, has been widely used in aircraft fuel tanks to reduce oxygen concentration, suppress fuel volatility, and improve flight safety. In recent years, the application of computational fluid dynamics in the aviation field has significantly advanced the numerical simulation research on the flow field and concentration distribution inside the fuel tank. Typical methods include finite volume method based on static geometric models and multiphase flow simulation. In addition, the rise of digital twin technology has provided a new path for real-time monitoring and dynamic simulation. By integrating sensor data and virtual models, it is possible to partially reflect the physical behavior under flight conditions. However, existing technologies are mostly focused on static or quasi-static simulation, and rarely consider the impact of vibration effects during flight on nitrogen injection. Moreover, data acquisition usually relies on offline analysis, making it difficult to achieve a balance between real-time performance and dynamic adaptability.

[0003] Existing technologies have significant shortcomings in simulating nitrogen injection in aircraft, mainly in the following aspects: First, the lack of system coupling for vibration effects leads to a large deviation between simulation results and actual flight conditions, especially in high-frequency vibration or turbulent environments, where the prediction accuracy of flow field and concentration distribution is limited; second, insufficient real-time performance, as traditional methods fail to fully utilize in-flight sensor data to update the model, making it difficult to dynamically reflect transient changes in nitrogen injection behavior; and third, limited visualization and decision support capabilities, as existing simulation results are mostly presented in static charts, lacking intuitive dynamic displays and real-time transmission of key indicators, which limits the control center's rapid response to fuel tank status. Summary of the Invention

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

[0005] Therefore, this invention provides a numerical simulation method that considers aircraft nitrogen injection to solve the problem of accurately simulating the dynamic behavior of nitrogen injection during aircraft flight.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a numerical simulation method considering nitrogen injection into an aircraft, comprising: constructing an initial digital twin model of an aircraft fuel tank using 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, and outputting time-series data; updating the digital twin model and coupling vibration effects to generate flow field changes, and outputting a real-time simulation model reflecting the flight status; simulating the velocity and concentration distribution of nitrogen injection, analyzing the impact of vibration, and outputting real-time flow field data; generating a three-dimensional visualization graphic using visualization tools, calculating nitrogen injection efficiency indicators and adding them to the three-dimensional visualization graphic, rendering and packaging the three-dimensional visualization graphic and transmitting it to the control center to display the distribution status and nitrogen injection efficiency indicators.

[0008] As a preferred embodiment of the numerical simulation method for aircraft nitrogen injection described in this invention, the specific steps for constructing an initial digital twin model of the aircraft fuel tank using computer-aided design software and computational fluid dynamics tools are as follows:

[0009] Set the top center as the nitrogen injection point using SolidWorks and output a 3D geometric model.

[0010] Import the 3D geometric model into ANSYS Fluent;

[0011] The unstructured mesh in ANSYS Fluent is used to spatially divide the partitions and boxes in the 3D geometric model and save them as mesh files;

[0012] Open the 3D geometric model, initialize the flow rate, pressure, and temperature of nitrogen injection, initialize the oxygen concentration distribution in the fuel tank, and output the aircraft physics configuration file.

[0013] Vibration characteristics are added to the top of the box in the 3D geometry model by setting the boundary in ANSYS Fluent, and the boundary condition file is output.

[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 the initial simulation;

[0015] The three-dimensional geometric model, mesh file, physics field configuration file, boundary condition file, and data interface configuration file are loaded and integrated to generate preliminary velocity and concentration distributions, and output an initial digital twin model.

[0016] As a preferred embodiment of the numerical simulation method for considering aircraft nitrogen injection described in this invention, the multiple 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 for aircraft nitrogen injection described in this invention, the specific steps for recording the vibration characteristics and real-time status of the recording chamber and outputting time-series data are as follows:

[0020] Vibration data and environmental parameters are combined using onboard data acquisition equipment to generate a unified flight data package;

[0021] By configuring the data interface in the initial digital twin model, the flight data packets are sent to the digital twin platform in JSON format via wireless transmission;

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

[0023] As a preferred embodiment of the numerical simulation method for considering aircraft nitrogen injection described in this invention, the steps of updating the digital twin model and coupling vibration effects to generate flow field changes and outputting a real-time simulation model reflecting the flight state are as follows:

[0024] Load the initial digital twin model and import time series data;

[0025] Environmental parameters are read from time-series data, mapped to the aircraft physics configuration file of the initial digital twin model, and saved as a new aircraft physics configuration file;

[0026] Read vibration data from time series data, replace the initial vibration characteristics, and save it as a new boundary condition file;

[0027] Wavelet transform was used to perform frequency domain analysis on vibration data in time series data. The decomposition level was set to three levels to separate vibration components of different frequencies.

[0028] By combining the new aircraft physics configuration file, the new boundary condition file, and the spatial segmentation in the mesh file, the dynamic influence of vibration characteristics on the nitrogen flow field is simulated.

[0029] Integrate the initial digital twin model, new aircraft physics configuration file, new boundary condition file, and 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 described in this invention, the steps for simulating the velocity and concentration distribution of nitrogen injection, analyzing the impact of vibration, and outputting real-time flow field data are as follows:

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

[0032] Nitrogen and oxygen were separated into multiple components. The simulation was started in ANSYS Fluent to simulate the diffusion process of nitrogen from the top center injection point into the interior of the tank and obtain real-time flow field data.

[0033] Load real-time flow field data, and determine whether nitrogen injection is reasonable based on the flow direction and velocity at the top injection point and the spatial changes inside the chamber;

[0034] If any anomalies are found, repeat the simulation until it stabilizes.

[0035] If no abnormalities are found, the real-time flow field data after inspection will be saved.

[0036] As a preferred embodiment of the numerical simulation method for considering aircraft nitrogen injection described in this invention, the specific steps for generating three-dimensional visualization graphics using visualization tools are as follows:

[0037] Log in to the digital twin platform and import 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] A vector diagram is generated based on the velocity distribution in the real-time flow field data, and a volume view is generated based on the concentration distribution in the real-time flow field data.

[0040] The rendering function is used to render vector and volume views, generating three-dimensional visualization graphics that show the velocity and concentration distribution of the real-time flow field of nitrogen injection inside the chamber.

[0041] As a preferred embodiment of the numerical simulation method for aircraft nitrogen injection described in this invention, the calculated nitrogen injection efficiency index is added to a three-dimensional visualization graphic, which is then rendered, packaged, and transmitted to the control center to display the distribution status and nitrogen injection efficiency index. The specific steps are as follows:

[0042] By using data analysis from a digital twin platform, the velocity and concentration distributions of the real-time flow field are analyzed, and nitrogen injection efficiency indicators are calculated.

[0043] Add the nitrogen injection efficiency index into the 3D visualization graphic, turn on video rendering, set the rendering parameters, and convert the 3D visualization graphic into a real-time video stream to show the dynamic changes of nitrogen injection.

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

[0045] The real-time video stream and nitrogen injection performance indicators are packaged and sent to the control center via an Ethernet interface.

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

[0047] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the numerical simulation method for considering aircraft nitrogen injection as described in the first aspect of the present invention.

[0048] The beneficial effects of this invention are as follows: This invention enhances the efficiency of numerical simulation of aircraft nitrogen injection through a digital twin platform. The initial digital twin model constructed by computer-aided design software and computational fluid dynamics tools achieves accurate digital mapping of the physical structure of the fuel tank, providing a high-fidelity foundation for the simulation. It receives and analyzes flight data packets collected by aircraft sensors, integrates vibration and environmental parameters into time series data, ensures a high degree of synchronization between the simulation input and the actual flight state, updates the digital twin model and couples vibration effects, generating a real-time simulation model that reflects dynamic flight conditions, breaking through the limitations of traditional static simulation. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a flowchart of the numerical simulation method considering nitrogen injection into an aircraft in Example 1.

[0051] Figure 2 This is a flowchart of generating 3D visualization graphics in Example 1. Detailed Implementation

[0052] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

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

[0054] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0055] Example 1, referring to Figure 1 and Figure 2 This is the first embodiment of the present invention, which 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 using computer-aided design software and computational fluid dynamics tools.

[0057] Furthermore, open the design drawings of the aircraft fuel tank in SolidWorks, draw the rectangular tank and partitions, set the top center as the nitrogen injection point, and output the three-dimensional geometric model.

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

[0059] Create a 3D geometric model using the "Parts" function in the computer-aided design software (SolidWorks): Click the "Sketch" tool to draw the bottom outline of the rectangular box and set it to a cuboid shape; generate the outer shell of the box using the "Extrude" function; then add a partition inside the box, draw the partition outline perpendicular to the bottom surface using the "Sketch" tool, and generate the partition solid using "Extrude"; finally, add a nitrogen injection point at the center of the top of the box (geometric center) and mark it as a circular opening;

[0060] Adjust the view angle and use the "Check Geometry" function to verify whether the box and partition meet the design drawing requirements, and confirm that the injection point position is without deviation;

[0061] Once finished, click the "File" menu, select the "Save" option, and save the drawn model as a SolidWorks part file (.SLDPRT format) as a 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 geometry file (.SLDPRT format) in the computer-aided design software (SolidWorks), clicks the "File" menu, and selects the "Save As" option;

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

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

[0066] After importing, check the 3D geometric model in the geometry editing interface of the computational fluid dynamics tool (ANSYS Fluent) to confirm that the shell, baffles and injection point positions are complete and correct, and avoid geometric loss during the import process;

[0067] The unstructured mesh in ANSYS Fluent is used to spatially divide the partitions and rectangular boxes in the 3D geometric model and save them as mesh files;

[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 "Automatic Mesh" option, and set the mesh density to medium level to ensure coverage of the box and partition areas, especially increasing the mesh density near the top injection point;

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

[0071] Select the "Save Mesh" option from the "File" menu to 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, initialize the oxygen concentration distribution in the fuel tank, and output the aircraft physics configuration file.

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

[0074] In the "Boundary Conditions" option, select the top center injection point, and enter the initial flow rate, pressure, and temperature values ​​for nitrogen injection, based on aerospace standards (specific values ​​are provided by design requirements). Confirm that the injection point location is correct.

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

[0076] Click the "Save Configuration" button to save these physics settings as an aircraft physics configuration file (.BCF format);

[0077] Vibration characteristics are added to the top of the box in the 3D geometry model using the software boundary setting function in ANSYS Fluent, and the boundary condition file is output.

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

[0079] Select the top surface of the enclosure, add vibration characteristics in the "Boundary Type" option, set it to periodic disturbance, 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 if the settings are correctly displayed on the surface of the 3D geometric model.

[0081] Select the "Save Boundary Conditions" option from the "File" menu 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), clicks the "Interface Management" option on the main interface, and selects the "Create Data Interface" function;

[0084] In the interface configuration interface, select the wireless transmission method, enter 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)). 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] The drawn 3D geometric model, mesh file, physics configuration file, boundary condition file and data interface configuration file are loaded and integrated into ANSYS Fluent to simulate the initial flow of nitrogen in the chamber, 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 loads the three-dimensional geometric model (STEP format), mesh file (.MSH format), aircraft physics configuration file (.BCF format), boundary condition file (.BCF format), and data interface configuration file (.JSON format) in sequence.

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

[0090] In the "Solve" menu, select the "Static Simulation" option and click the "Run" button. The computational fluid dynamics tool (ANSYS Fluent) simulates the initial flow of nitrogen in the tank based on the mesh file, physics configuration file, and boundary condition file, generating velocity distribution data (describing the direction of nitrogen flow) and concentration distribution data (displaying the distribution of nitrogen and oxygen).

[0091] After the simulation is complete, check the results interface to confirm whether the distribution of nitrogen from the top injection point is reasonable, and save it as an initial flow field data file (.DAT format), named 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 physics configuration file (.BCF format), boundary condition file (.BCF format), and data interface configuration file (.JSON format)) and initial flow field data file into an initial digital twin model (.CAS format);

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

[0094] S2. Using multiple sensors installed on the aircraft, flight data is collected, the vibration characteristics and real-time status of the enclosure are recorded, and time series data is output.

[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, the accelerometer (ADXL345) is activated via a data acquisition device (Raspberry Pi 4) and installed at the center of the top of the fuel tank, aligning with the injection point of the three-dimensional geometric model (.SLDPRT and .STEP formats);

[0098] The accelerometer measures the vibration data (speed and amplitude) of the top of the box in real time at different flight stages, with the direction perpendicular to the top and consistent with the boundary condition file (.BCF format);

[0099] The environmental sensor group, including a pressure sensor (BMP280), a temperature sensor (DS18B20), and an oxygen concentration sensor (KE-25), is activated by a data acquisition device and installed on the inner wall of the fuel tank.

[0100] The environmental sensor array measures pressure, temperature, and oxygen concentration data inside the chamber in real time, generating environmental parameters that reflect the real-time status of the chamber.

[0101] Vibration data and environmental parameters are merged using the data acquisition equipment on the aircraft to generate a unified flight data packet. The transmission protocol is defined and the transmission frequency is set to a fixed interval through the data interface configuration file in the initial digital twin model. The flight data packet is then sent to the digital twin platform in JSON format via wireless transmission.

[0102] Specifically, the "data integration" function is activated in the data acquisition equipment on the aircraft, and the data input interface is opened;

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

[0104] The data acquisition equipment integrates these raw data into a unified dataset, ensuring that each set of data includes time points, vibration speed, vibration amplitude, pressure value, temperature value, and oxygen concentration value, generating unified flight data;

[0105] In the data acquisition device, open the "Transmission Settings" interface, select the "Frequency Configuration" option, and set the transmission frequency to a fixed interval (e.g., once per second) to ensure data real-time performance.

[0106] The data acquisition equipment converts the unified flight data into a standard JSON format. Each data packet contains a timestamp (e.g., "timestamp"), vibration rate (e.g., "frequency"), vibration amplitude (e.g., "amplitude"), pressure value (e.g., "pressure"), temperature value (e.g., "temperature"), and oxygen concentration value (e.g., "oxygen").

[0107] Click the "Package" button to generate a JSON data package, ensuring a clear data structure for easy subsequent parsing;

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

[0109] The data acquisition device sends JSON format data packets (unified flight data) to the digital twin platform (Siemens MindSphere) via a wireless channel. The data acquisition device monitors the transmission status in real time to ensure that each JSON format data packet is sent at a fixed interval (such as once per second). Each data packet contains a timestamp, vibration rate, vibration amplitude, pressure value, temperature value, and oxygen concentration value.

[0110] If the wireless signal is interrupted, the data acquisition device caches JSON format data packets (unified flight data) and resends them after the signal is restored, ensuring that the JSON format data packets (unified flight data) arrive at the digital twin platform (SiemensMindSphere) at fixed intervals;

[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 enclosure, extracts environmental parameters as the real-time status of the enclosure, and organizes them in chronological order to save 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 package (Unified Flight Data);

[0113] Once the "Real-time Reception" function is activated, the digital twin platform (Siemens MindSphere) receives the transmitted JSON format data packets (Unified Flight Data), loads the data for processing, and confirms that each data packet contains a timestamp and complete data fields (vibration speed, amplitude, pressure, temperature, oxygen concentration).

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

[0115] In the digital twin platform (Siemens MindSphere), open the "Data Parsing" function, 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 JSON format data packets, defining it as the vibration characteristics of the enclosure, reflecting the dynamic behavior of the enclosure during flight; it also extracts environmental parameters (pressure data, temperature data, oxygen concentration data), defining them as the real-time status of the enclosure, reflecting the environmental conditions inside the enclosure.

[0117] Check the extraction results to ensure that the vibration characteristics and real-time status are consistent with the data packet content, and that there are no missing or incorrect data fields.

[0118] In the digital twin platform (Siemens MindSphere), open the "Data Processing" function to sort the extracted vibration characteristics and real-time status by time stamp to form continuous time series data;

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

[0120] Click the "Save" button to save the processed time series data as a time series data file (.CSV format), name it Real-time Data Export File, and store it in the database of the digital twin platform (Siemens MindSphere).

[0121] It should be noted that by utilizing multiple sensors to collect flight data and output time-series data, the dynamics of nitrogen injection simulation are improved. Acceleration and environmental sensors installed on the aircraft fuel tank capture vibration characteristics and state parameters in real time. The data acquisition equipment integrates and generates JSON format flight data packets, which are wirelessly transmitted to the digital twin platform for parsing and processing into time series, reflecting the actual behavior of the tank during flight. This achieves efficient acquisition and transmission of sensor data, ensuring the real-time and synchronous nature of the simulation compared to traditional offline data, and enhancing the accuracy of nitrogen injection effect prediction.

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

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

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

[0125] The initial digital twin model was successfully loaded using the model editing interface of the computational fluid dynamics tool (ANSYS Fluent). It was confirmed that the positions of the outer shell, partition and top center injection point in the 3D geometric model were correct and the mesh file covered the space completely.

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

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

[0128] Environmental parameters are read from time-series data, mapped to the aircraft physics configuration file of the initial digital twin model, the pressure, temperature and oxygen concentration distribution inside the container are updated, and saved as a new aircraft physics configuration file.

[0129] Specifically, in the computational fluid dynamics tool (ANSYS Fluent), open the "Physics Settings" interface, select the initial aircraft physics 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 (.CSV format), including pressure data (corresponding to the air pressure inside the chamber), temperature data (corresponding to the air temperature inside the chamber), and oxygen concentration data (corresponding to the oxygen distribution inside the chamber);

[0131] The read environmental parameters are mapped to the initial aircraft physics configuration file, and the pressure, temperature and oxygen concentration distribution inside the container are updated, while keeping 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 chamber reflects real-time data (such as changes in pressure, temperature, and oxygen concentration).

[0133] Select the "Save Configuration" option from the "File" menu to save the updated physics parameters as a new aircraft physics configuration file (.BCF format);

[0134] Vibration data is read from time series data, converted into periodic data format, replaced with the initial vibration characteristics, updated the boundary conditions, and saved as a new boundary condition file.

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

[0136] Vibration data, including speed (frequency) and amplitude, is read from the imported time series data file (.CSV format) and extracted as the real-time vibration characteristics of the enclosure.

[0137] Convert the vibration data into a periodic data format (such as sine wave form) that is consistent with the direction defined in the initial boundary condition file (perpendicular to the top), 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 top boundary conditions of the enclosure and check whether the vibration characteristics are correctly displayed on the top surface;

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

[0140] Wavelet transform was used to perform frequency domain analysis on vibration data in time series data. The decomposition level was set to three levels to separate vibration components of different frequencies.

[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 coefficients A1.

[0142] High-frequency components of vibration data are extracted using a high-pass filter to generate the first layer of detail coefficients D1.

[0143] The second-level decomposition extracts the low-frequency components in A1 using a low-pass filter, generating the approximation coefficients A2 for the second level.

[0144] High-frequency components in A1 are extracted using a high-pass filter to generate the detail coefficients D2 for the second layer.

[0145] The third-level decomposition extracts the low-frequency components in A2 using a low-pass filter, generating the approximation coefficients A3 for the third level.

[0146] High-frequency components in A2 are extracted using a high-pass filter to generate the detail coefficients D3 for the third layer.

[0147] The approximation coefficient A3 of the third-level decomposition is mapped as a low-frequency vibration component to the new boundary condition file to update the vibration characteristics;

[0148] The D1, D2, and D3 detail coefficients of the first, second, and third layer decompositions are merged into high-frequency vibration components through inverse wavelet transform and mapped to the new aircraft physics field profile to update the nitrogen flow field (high-frequency perturbations in the nitrogen flow field).

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

[0150] The high-frequency vibration components are merged through inverse wavelet transform D1+D2+D3, where D1, D2, and D3 are all the high-frequency detail coefficients generated by the three-level decomposition, covering the entire high-frequency range of the vibration data. After merging through inverse wavelet transform, the complete high-frequency vibration components are recovered, which are suitable for mapping to the new aircraft physics field profile and updating the nitrogen flow field (high-frequency disturbances in the flow field).

[0151] By combining the new aircraft physics configuration file, the new boundary condition file, and the spatial segmentation in the mesh file, the dynamic influence of vibration characteristics on the nitrogen flow field is simulated to 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, and set the time step to be consistent with the transmission frequency of the time series data (e.g., once per second) to ensure that the simulation is synchronized with the real-time data.

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

[0154] The velocity distribution is a periodic fluctuation that changes the speed (frequency) of the vibration, which affects the flow intensity of nitrogen. For example, when there is no vibration, nitrogen flows smoothly downward from the top injection point with a uniform velocity distribution. When there is vibration, the top vibration introduces periodic disturbances, and the velocity distribution fluctuates. For example, high-frequency vibration may lead to the formation of local vortices near the top, and large-amplitude vibration may enhance the downward flow and affect the overall flow field of the box.

[0155] The concentration distribution is determined by the nitrogen diffusion path disturbed by vibration. High-frequency vibration accelerates mixing, while large-amplitude vibration can lead to localized uneven concentration. The concentration distribution is dynamically adjusted over time. Without vibration, nitrogen is injected from the top, and the concentration distribution gradually becomes uniform with diffusion. With vibration, the diffusion path is disturbed. The speed of vibration affects the mixing rate, and the amplitude affects the range of disturbance. For example, high-frequency vibration accelerates the mixing of nitrogen and oxygen, while large-amplitude vibration may cause a temporary accumulation of concentration at the top.

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

[0157] In the computational fluid dynamics tool (ANSYS Fluent), click the "Calculate" button, run several iterations (e.g., 100 times), monitor the calculation stability (residual convergence), and generate real-time flow field data, including velocity distribution (dynamic changes in nitrogen flow) and concentration distribution (dynamic distribution of nitrogen 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, new aircraft physics configuration file, new boundary condition file, and 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 physics 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 and mesh file with the new aircraft physics configuration file and real-time flow field data file to ensure that the vibration characteristics and real-time status are correctly applied;

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

[0163] It should be noted that by updating the digital twin model and coupling vibration effects, a real-time simulation model reflecting the flight state is output, which significantly improves 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 influence of vibration on the flow field, outputs real-time flow field data, and integrates and generates a real-time simulation model, realizing accurate dynamic simulation of nitrogen injection behavior under flight conditions. Compared with traditional static methods, it enhances the response capability to vibration disturbances.

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

[0165] Furthermore, a real-time simulation model of the flight status is loaded;

[0166] Specifically, launch 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 flight status, and click the "Open" button to load it. The real-time simulation model of flight status includes a three-dimensional geometric model, a mesh file, a new aircraft physics configuration file (including real-time pressure, temperature, and oxygen concentration), a new boundary condition file (including real-time vibration characteristics), and a 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 has been successfully loaded, check whether the positions of the box shell, baffle and top center injection point in the three-dimensional geometric model are correct, the mesh file covers the entire space completely, and the real-time flow field data reflects the impact of vibration.

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

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

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

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

[0173] Nitrogen and oxygen were divided into multiple components. The simulation function was started in ANSYS Fluent. Combining the new aircraft physics configuration file, new boundary condition file and mesh file, the process of nitrogen diffusion from the top center injection point into the interior of the box was simulated to obtain real-time flow field data.

[0174] Specifically, in the computational fluid dynamics tool (ANSYS Fluent), open the "Materials" menu, select the "Multi-component Model" option, define nitrogen and oxygen as the main components, enable the multi-component simulation function, and ensure that the mixing process of nitrogen and oxygen in the box is simulated after nitrogen is injected.

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

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

[0177] Click the "Initialize" button to start the fluid dynamics calculation using the real-time flow field data file as the starting point, and simulate the process of nitrogen gas diffusing from the top center injection point into the interior of the box.

[0178] Continue running the transient simulation in the computational fluid dynamics tool (ANSYS Fluent), and calculate the flow field changes after nitrogen injection based on the spatial characteristics of the mesh file segmentation 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 direction and velocity of nitrogen flow, which is affected by the speed and amplitude of vibration, such as local eddies caused by high-frequency vibration) and concentration distribution (describing the spatial changes of nitrogen and oxygen in the chamber, which are affected by the diffusion path of vibration disturbance).

[0180] Run several iterations (e.g., 100 times), monitor computational stability (residual convergence), and ensure that the simulation results reflect the dynamic influence 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 real-time flow field data, check the velocity and concentration distribution of nitrogen injection, and determine whether nitrogen injection is reasonable based on the flow direction and velocity at the top injection point and the spatial changes inside the chamber.

[0183] Specifically, in the computational fluid dynamics tool (ANSYS Fluent), open the "Results View" interface, 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 to confirm whether the flow direction and velocity of nitrogen from the top injection point are reasonable (e.g., whether the fluctuations under the influence of vibration are as expected);

[0185] Check the concentration distribution to confirm whether the spatial variation of nitrogen and oxygen in the chamber is reasonable (e.g., high concentration at the top and uniform diffusion at the bottom).

[0186] If any anomalies are found (such as abnormal fluctuations in velocity distribution or uneven concentration distribution), return to the "Solve" menu and repeat the simulation until it stabilizes.

[0187] If no abnormalities are found, the real-time flow field data after inspection will be saved.

[0188] It should be noted that by collecting real-time vibration data (frequency and amplitude) and environmental parameters (pressure, temperature, oxygen concentration) from the aircraft fuel tank, the impact of vibration on the nitrogen flow field is accurately simulated using ANSYS Fluent and wavelet transform. After integrating the data from the accelerometer and environmental sensor, time-series data is generated, the digital twin model is updated, the nitrogen injection efficiency is optimized, the tank safety and flight stability are enhanced, the velocity and concentration distribution are dynamically simulated, the periodic impact of vibration disturbance on the flow field is revealed, the real-time monitoring accuracy is improved, and potential risks are reduced.

[0189] S5. Generate a 3D visualization graphic using visualization tools, calculate the nitrogen injection efficiency index and add it to the 3D visualization graphic, render and package the 3D visualization graphic and transmit it to the control center to display the distribution status and nitrogen injection efficiency index.

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

[0191] Specifically, open your browser, enter the login address of the digital twin platform (Siemens MindSphere), enter your 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, locate the real-time flow field data file, click the "Open" button to import it, and confirm the file name (e.g., "Real-time Flow Field Export File").

[0194] After the message "Data import successful" is displayed, check the imported data fields to ensure that velocity distribution and concentration distribution are included.

[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 Tools" icon on the main interface of the digital twin platform (Siemens MindSphere) to launch the built-in visualization tools;

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

[0198] Speed ​​distribution is as follows: Select "Vector Display", set the arrow size ratio (e.g., 0.1) and color range (e.g., blue for low speed to red for high speed);

[0199] Concentration distribution: Select "Stereoscopic Display" and set the concentration color gradient (e.g., from low concentration in blue to high concentration in red);

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

[0201] Check the loading status to ensure that the data display is correct (e.g., the velocity vector and concentration distribution previews are visible);

[0202] A vector diagram is generated based on the velocity distribution in the real-time flow field data, and a volume view is generated based on the concentration distribution in the real-time flow field data.

[0203] Specifically, in the visualization tool, click the "Generate Graphics" menu, select the "Vector Graphics" option, and generate a three-dimensional vector graphic based on the velocity distribution data in the real-time flow field data to show the direction and speed of nitrogen flow;

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

[0205] Check the generated vector and volume views to ensure that the arrow direction in the vector view is consistent with the velocity distribution, the color reflects the velocity change, and the color gradient in the volume view matches the density distribution (e.g., the high density at the top is red).

[0206] The rendering function is used to render vector and volume views to generate three-dimensional visualization graphics, showing the velocity and concentration distribution of the real-time flow field of nitrogen injection inside the chamber;

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

[0208] Click the "Render" button to render the vector and volume view, generating a 3D visualization that shows the real-time flow field (velocity distribution and concentration distribution) of nitrogen injection inside the chamber.

[0209] By using data analysis from a digital twin platform, the velocity and concentration distributions of the real-time flow field are analyzed, and nitrogen injection efficiency indicators are calculated.

[0210] The expression for average velocity is:

[0211]

[0212] The expression for the average nitrogen concentration is:

[0213]

[0214] The expression for the standard deviation of nitrogen concentration is:

[0215]

[0216] The expression for the average oxygen concentration is:

[0217]

[0218] The overall performance expression is:

[0219]

[0220] in, The average velocity represents the average speed of nitrogen flow within the chamber, measured in 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 spatially discretized points within the chamber. It has no unit and is defined by the grid file. For example, if the chamber is divided into 1 million grid points, then N = 1,000,000. i represents the velocity magnitude at the i-th grid point, in meters per second (m / s). It is a single value in the velocity distribution of the real-time flow field data, indicating the flow velocity of nitrogen at that point, and is the vector modulus (magnitude). |v i| is the absolute value (modulus) of the velocity. Ensure that all velocity values in the calculation are positive to avoid direction cancellation. is the average factor. Divide the sum by the number of grid points to obtain the average value. is the average value of the nitrogen concentration, representing the average nitrogen concentration in the chamber, in percentage (%). It is the average of the nitrogen concentrations at all grid points. μ is the average of the nitrogen concentrations at all grid points in the chamber. is the nitrogen concentration at the i-th grid point, in percentage (%). It 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 the nitrogen concentration, in percentage (%). It is a statistical indicator measuring the dispersion degree of the 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 of the nitrogen concentration at the i-th grid point from the average value, in percentage (%). μ O2 is the average value of the oxygen concentration, representing the average oxygen concentration in the chamber, in percentage (%). It is the average of the 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 (%). It 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. It 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 indicates excellent efficiency (strong flow, high uniformity, low oxygen);

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

[0224] E ≤ 5 indicates poor efficiency;

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

[0226] Add the calculated nitrogen injection efficiency index to the three-dimensional visualization graph to generate the three-dimensional visualization graph result with the index;

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

[0228] Specifically, in the visualization tool, click on the "Video Rendering" menu, 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 based on time series data (e.g., 30 seconds);

[0233] Click the "Render" button to convert the 3D visualization with indicators into a real-time video stream, showing the dynamic changes during nitrogen injection.

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

[0235] In page design, an interactive interface is generated based on the real-time video stream and saved 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 playback controls (such as play, pause, fast forward);

[0238] Add interactive features:

[0239] Zoom: Enable mouse wheel zoom to view partial views of the enclosure;

[0240] Rotate: Enables mouse drag rotation, supporting multi-angle viewing;

[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] The real-time video stream and key metrics are packaged (formatted as JSON) and sent to the control center via an Ethernet interface;

[0243] It should be noted that the real-time video stream (MP4 format) is a dynamic display generated by converting a 3D visualization graphic with indicators;

[0244] Nitrogen injection performance index (E) is a separately calculated key indicator, stored in JSON format;

[0245] The real-time video stream and nitrogen injection performance metrics are combined into a single data packet and sent over Ethernet.

[0246] It should be noted that by using real-time flow field and concentration distribution to generate visualization results and transmitting them to the control center, the visualization and decision support capabilities of nitrogen injection effect are improved. By loading data through the digital twin platform, generating vector and volume views and rendering 3D graphics, and combining nitrogen injection efficiency indicators, video streams and interactive interfaces are output, and the distribution status and key indicators are transmitted and displayed in real time. This achieves an intuitive presentation and quantitative evaluation of the dynamic process of nitrogen injection. Compared with traditional static display, it enhances the control center's ability to monitor and analyze the status of the container in real time.

[0247] This embodiment also provides a computer device suitable for numerical simulation methods 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 as proposed in the above embodiment.

[0248] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0249] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the numerical simulation method for considering aircraft nitrogen injection as proposed in the above embodiments. 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 (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0250] In summary, this invention enhances the efficiency and application value of numerical simulation of aircraft nitrogen injection through a digital twin platform. The initial digital twin model constructed using computer-aided design software and computational fluid dynamics tools achieves accurate digital mapping of the fuel tank's physical structure, providing a high-fidelity foundation for the simulation. It receives and analyzes flight data packets collected by aircraft sensors, integrates vibration and environmental parameters into time-series data, ensuring a high degree of synchronization between the simulation input and the actual flight state. By updating the digital twin model and coupling vibration effects, a real-time simulation model reflecting dynamic flight conditions is generated, overcoming 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 are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A numerical simulation method considering nitrogen injection into an aircraft, characterized in that: include, An initial digital twin model of the aircraft fuel tank was constructed using computer-aided design software and computational fluid dynamics tools. Using multiple sensors installed on the aircraft, flight data is collected, the vibration characteristics and real-time status of the enclosure are recorded, and time-series data is output. The digital twin model is updated and coupled with vibration effects to generate flow field changes, outputting a real-time simulation model that reflects the flight state; Simulate the velocity and concentration distribution of nitrogen injection, analyze the impact of vibration, and output real-time flow field data; A 3D visualization graphic is generated using visualization tools. Nitrogen injection efficiency indicators are calculated and added to the 3D visualization graphic. The 3D visualization graphic is then rendered and packaged and transmitted to the control center to display the distribution status and nitrogen injection efficiency indicators. The specific steps for constructing an initial digital twin model of the aircraft fuel tank using computer-aided design software and computational fluid dynamics tools are as follows: Set the top center as the nitrogen injection point using SolidWorks and output a 3D geometric model. Import the 3D geometric model into ANSYS Fluent; The unstructured mesh in ANSYS Fluent is used to spatially divide the partitions and boxes in the 3D geometric model and save them as mesh files; Open the 3D geometric model, initialize the flow rate, pressure, and temperature of nitrogen injection, initialize the oxygen concentration distribution in the fuel tank, and output the aircraft physics configuration file. Vibration characteristics are added to the top of the box in the 3D geometry model by setting the boundary in ANSYS Fluent, and the boundary condition file is output. 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 the initial simulation; The three-dimensional geometric model, mesh file, physics configuration file, boundary condition file, and data interface configuration file are loaded and integrated to generate preliminary velocity and concentration distributions, and output an initial digital twin model.

2. The numerical simulation method considering aircraft nitrogen injection as described in claim 1, characterized in that: The various sensors include an acceleration sensor, a pressure sensor, a temperature sensor, and an oxygen concentration sensor; The flight data includes vibration data and environmental parameters; The environmental parameters include pressure data, temperature data, and oxygen concentration data.

3. The numerical simulation method considering aircraft nitrogen injection as described in claim 2, characterized in that: The recording box's vibration characteristics and real-time status are recorded, and time-series data is output. The specific steps are as follows: Vibration data and environmental parameters are combined using onboard data acquisition equipment to generate a unified flight data package; By configuring the data interface in the initial digital twin model, the flight data packets are sent to the digital twin platform in JSON format via wireless transmission; The digital twin platform receives and parses flight data packets, extracts vibration data as the vibration characteristics of the enclosure, extracts environmental parameters as the real-time status of the enclosure, organizes them in chronological order, and saves them as time series data.

4. The numerical simulation method considering aircraft nitrogen injection as described in claim 3, characterized in that: The process involves updating the digital twin model and coupling it with vibration effects to generate flow field changes, outputting a real-time simulation model that reflects the flight state. The specific steps are as follows: Load the initial digital twin model and import time series data; Environmental parameters are read from time-series data, mapped to the aircraft physics configuration file of the initial digital twin model, and saved as a new aircraft physics configuration file; Read vibration data from time series data, replace the initial vibration characteristics, and save it as a new boundary condition file; Wavelet transform was used to perform frequency domain analysis on vibration data in time series data. The decomposition level was set to three levels to separate vibration components of different frequencies. By combining the new aircraft physics configuration file, the new boundary condition file, and the spatial segmentation in the mesh file, the dynamic influence of vibration characteristics on the nitrogen flow field is simulated. Integrate the initial digital twin model, new aircraft physics configuration file, new boundary condition file, and real-time flow field data in ANSYS Fluent to output a real-time simulation model of the flight state.

5. The numerical simulation method considering aircraft nitrogen injection as described in claim 4, characterized in that: The simulated nitrogen injection velocity and concentration distribution, analysis of vibration effects, and output of 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 ​​for nitrogen injection; Nitrogen and oxygen were separated into multiple components. The simulation was started in ANSYS Fluent to simulate the diffusion process of nitrogen from the top center injection point into the interior of the tank and obtain real-time flow field data. Load real-time flow field data, and determine whether nitrogen injection is reasonable based on the flow direction and velocity at the top injection point and the spatial changes inside the chamber; If any anomalies are found, repeat the simulation until it stabilizes. If no abnormalities are found, the real-time flow field data after inspection will be saved.

6. The numerical simulation method considering aircraft nitrogen injection as described in claim 5, characterized in that: The specific steps for generating 3D visualization graphics using visualization tools are as follows: Log in to the digital twin platform and import 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; A vector diagram is generated based on the velocity distribution in the real-time flow field data, and a volume view is generated based on the concentration distribution in the real-time flow field data. The rendering function is used to render vector and volume views, generating three-dimensional visualization graphics that show the velocity and concentration distribution of the real-time flow field of nitrogen injection inside the chamber.

7. The numerical simulation method considering aircraft nitrogen injection as described in claim 6, characterized in that: The calculated nitrogen injection efficiency index is added to the 3D visualization graphic, which is then rendered, packaged, and transmitted to the control center to display the distribution status and nitrogen injection efficiency index. The specific steps are as follows: By using data analysis from a digital twin platform, the velocity and concentration distributions of the real-time flow field are analyzed, and nitrogen injection efficiency indicators are calculated. Add the nitrogen injection efficiency index into the 3D visualization graphic, turn on video rendering, set the rendering parameters, and convert the 3D visualization graphic into a real-time video stream to show the dynamic changes of nitrogen injection. In page design, an interactive interface is generated based on the real-time video stream; The real-time video stream and nitrogen injection performance indicators are packaged and sent to the control center.

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