Numerical simulation method and numerical simulation device for subway train fire

Abstract

The present application provides a numerical simulation method and numerical simulation device for a subway train fire. The method comprises: importing an original three-dimensional model of a subway car into FDS software, and setting fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model used for simulating a fire in the subway car; and for each air conditioning operation mode of an air conditioning system in the subway car, performing numerical computation on the simulation model in the air conditioning operation mode by means of the FDS software, to obtain curves of fire simulation data changing with time at different preset positions in the subway car in the air conditioning operation mode, so as to evaluate, on the basis of the curves of fire simulation data changing with time, the impact of the use of the air conditioning operation mode on people evacuation when a fire occurs in the subway car. The method and the device improve the accuracy and diversity of numerical simulation of subway train fires.

Description

Numerical simulation method and numerical simulation device for subway train fire

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202311076334.2 filed with the State Intellectual Property Office of China on August 24, 2023, entitled “A numerical simulation method and numerical simulation device for subway train fires,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of numerical simulation technology, and in particular to a numerical simulation method and numerical simulation device for subway train fires. Background Art

[0004] With the continued development of urban construction in my country, the construction of urban rail transit systems has become an important means of alleviating traffic congestion in medium and large cities. In recent years, major subway fire accidents have occurred frequently both domestically and internationally. High-temperature smoke and toxic gases generated by vehicle fires are the primary factors contributing to casualties.

[0005] To create a pleasant riding environment, vehicle air conditioning systems are often kept running. When a fire occurs, the TCMS system shuts down the air conditioning system upon receiving a signal from the fire detector. Furthermore, the reliability of fire alarms decreases over time. Therefore, in the early stages of a fire, before the heat and smoke generated by the fire have activated the fire alarm, a properly functioning air conditioning system will alter the temperature and smoke distribution within the vehicle, potentially affecting passenger evacuation. Therefore, accurately studying the impact of a vehicle's air conditioning system's operating status on the evacuation process during a vehicle fire is a significant technical challenge.

[0006] Summary of the Invention

[0007] In view of this, the purpose of this application is to provide a numerical simulation method and numerical simulation device for subway train fires. Through the numerical simulation method, the temperature, visibility, toxic gas concentration at the characteristic height of personnel in the subway car and the temperature under the car roof are calculated under different air-conditioning operation modes after a fire occurs at a typical fire location in the subway car, thereby improving the accuracy and diversity of the numerical simulation of subway train fires and providing a data basis for analyzing the impact of the operation of the air-conditioning system on the personnel evacuation process.

[0008] In a first aspect, an embodiment of the present application provides a numerical simulation method for a subway train fire, the numerical simulation method comprising:

[0009] Obtaining a front view and a top view corresponding to a subway car, and establishing an original three-dimensional model corresponding to the subway car based on the front view and the top view;

[0010] Importing the original three-dimensional model into FDS software, and setting fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car;

[0011] For each air-conditioning operation mode of the air-conditioning system in the subway car, numerical calculations are performed on the simulation model in the FDS software under the air-conditioning operation mode to obtain a time-varying curve of fire simulation data at different preset positions in the subway car under the air-conditioning operation mode, so as to evaluate the impact of the air-conditioning operation mode on the evacuation of personnel when a fire occurs in the subway car based on the time-varying curve of fire simulation data; wherein, the air-conditioning operation modes include an off mode, an air-conditioning mode, and a ventilation mode, and the fire simulation data include the contact temperature at a characteristic height of personnel in the subway car, the visibility at the characteristic height of personnel, and the temperature of the subway car roof.

[0012] Furthermore, establishing an original three-dimensional model corresponding to the subway car according to the front view and the top view includes:

[0013] Determining the size of the subway car according to the front view and the top view;

[0014] determining the physical structure of the subway car according to the front view and the top view;

[0015] An original three-dimensional model corresponding to the subway car is established according to the car size and the physical structure.

[0016] Furthermore, setting fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car includes:

[0017] In the FDS software, the initial state of the flow field in the original three-dimensional model is set to a preset state, the temperature in the simulation area of ​​the original three-dimensional model and the ambient temperature outside the simulation area are both preset temperatures, the pressure in the original three-dimensional model is a preset pressure value, the preset position in the original three-dimensional model is the fire source position, the fire source size is a preset size, and the ignition mode of the fire source is a preset mode, so as to obtain the simulation model.

[0018] Furthermore, before performing numerical calculation on the simulation model in the air-conditioning operation mode using the FDS software, the numerical simulation method further includes:

[0019] Based on a preset fire occurrence time point and a preset running state corresponding to the train to which the subway car belongs, an evacuation time point for opening the car door to evacuate people is determined when a fire occurs in the subway car.

[0020] Furthermore, when the air conditioning operation mode is the off mode, the numerical calculation of the simulation model in the air conditioning operation mode is performed using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air conditioning operation mode, including:

[0021] Setting the air conditioning system in the simulation model to a closed state based on the closed mode;

[0022] Taking the preset fire occurrence time point as a starting point, using the FDS software to perform fire numerical simulation on the simulation model, and determining fire simulation data for each preset location in the subway car at each time point within a first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point;

[0023] Assuming that the car door in the simulation model is open, using the FDS software to perform a fire numerical simulation on the simulation model, and determining the fire simulation data at each preset location in the subway car at each time point within a second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point;

[0024] A curve of fire simulation data changing over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

[0025] Furthermore, when the air conditioning operation mode is the air conditioning mode, the numerical calculation of the simulation model in the air conditioning operation mode is performed using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air conditioning operation mode, including:

[0026] Based on the air conditioning mode, the air supply temperature of the air conditioning system in the simulation model is set to a first preset temperature, and the total air supply volume of the air conditioning system is set to a first preset air supply volume;

[0027] Taking the preset fire occurrence time point as a starting point, using the FDS software to perform fire numerical simulation on the simulation model, and determining fire simulation data for each preset location in the subway car at each time point within a first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point;

[0028] Assuming that the car door in the simulation model is open, using the FDS software to perform a fire numerical simulation on the simulation model, and determining the fire simulation data at each preset location in the subway car at each time point within a second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point;

[0029] A curve of fire simulation data changing over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

[0030] Furthermore, when the air conditioning operation mode is the ventilation mode, the numerical calculation of the simulation model in the air conditioning operation mode is performed using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air conditioning operation mode, including:

[0031] Based on the ventilation mode, the air supply temperature of the air conditioning system in the simulation model is set to a second preset temperature, and the total air supply volume of the air conditioning system is set to a second preset air supply volume;

[0032] Taking the preset fire occurrence time point as a starting point, using the FDS software to perform fire numerical simulation on the simulation model, and determining fire simulation data for each preset location in the subway car at each time point within a first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point;

[0033] Assuming that the car door in the simulation model is open, using the FDS software to perform a fire numerical simulation on the simulation model, and determining the fire simulation data at each preset location in the subway car at each time point within a second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point;

[0034] A curve of fire simulation data changing over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

[0035] In a second aspect, an embodiment of the present application further provides a numerical simulation device for a subway train fire, the numerical simulation device comprising:

[0036] a three-dimensional model building module, configured to obtain a front view and a top view corresponding to the subway car, and to build an original three-dimensional model corresponding to the subway car based on the front view and the top view;

[0037] a simulation model building module, configured to import the original three-dimensional model into FDS software and set fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car;

[0038] A fire numerical simulation module is used to perform numerical calculations on the simulation model in the FDS software for each air-conditioning operation mode of the air-conditioning system in the subway car under the air-conditioning operation mode, thereby obtaining a time-varying curve of fire simulation data at different preset positions in the subway car under the air-conditioning operation mode, so as to evaluate the impact of the air-conditioning operation mode on the evacuation of personnel when a fire occurs in the subway car based on the time-varying curve of fire simulation data; wherein the air-conditioning operation modes include an off mode, an air-conditioning mode, and a ventilation mode, and the fire simulation data include the contact temperature at a characteristic height of personnel in the subway car, the visibility at the characteristic height of personnel, and the temperature of the subway car roof.

[0039] In a third aspect, an embodiment of the present application further provides an electronic device comprising: a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor and the memory communicate via the bus, and when the machine-readable instructions are executed by the processor, the steps of the numerical simulation method for subway train fires as described above are performed.

[0040] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, executes the steps of the numerical simulation method for subway train fires as described above.

[0041] The numerical simulation method and numerical simulation device for subway train fires provided in the embodiments of the present application are first used to obtain a front view and a top view corresponding to a subway car, and establish an original three-dimensional model corresponding to the subway car based on the front view and the top view; then, the original three-dimensional model is imported into FDS software, and fire simulation parameters are set for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car; finally, for each air-conditioning operation mode of the air-conditioning system in the subway car, the simulation model is numerically calculated using the FDS software under the air-conditioning operation mode to obtain a time-varying curve of fire simulation data at different preset positions in the subway car under the air-conditioning operation mode, so as to evaluate the impact of using the air-conditioning operation mode on the evacuation of personnel when a fire occurs in the subway car based on the time-varying curve of the fire simulation data.

[0042] This application uses numerical simulation methods to calculate the temperature, visibility, toxic gas concentration, and temperature under the car roof at characteristic heights of occupants in subway cars under different air-conditioning operation modes after a fire breaks out at a typical fire location in the car. This improves the accuracy and diversity of numerical simulations of subway train fires and provides a data basis for analyzing the impact of air-conditioning system operation on the evacuation process.

[0043] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0045] FIG1 is a flow chart of a numerical simulation method for a subway train fire provided in an embodiment of the present application;

[0046] FIG2 is a schematic diagram of a train running state change according to an embodiment of the present application;

[0047] FIG3(a) to FIG3(d) are graphs showing changes in visibility over time at a characteristic height of a human body in a vehicle compartment according to an embodiment of the present application;

[0048] Figures 4(a) to 4(d) are graphs showing the temperature change over time under a roof panel in a vehicle compartment according to an embodiment of the present application;

[0049] FIG5(a) to FIG5(d) are graphs showing changes in toxic gas concentration over time at a characteristic height of a human body in a vehicle compartment according to an embodiment of the present application;

[0050] FIG6 is a schematic structural diagram of a numerical simulation device for a subway train fire provided in an embodiment of the present application;

[0051] FIG7 is a schematic structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for which protection is claimed, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, each other embodiment obtained by those skilled in the art without making creative work falls within the scope of protection of the present application.

[0053] First, the application scenarios to which this application is applicable are introduced. This application can be applied in the field of numerical simulation technology.

[0054] With the continued development of urban construction in my country, the construction of urban rail transit systems has become an important means of alleviating traffic congestion in medium and large cities. In recent years, major subway fire accidents have occurred frequently both domestically and internationally. High-temperature smoke and toxic gases generated by vehicle fires are the primary factors contributing to casualties.

[0055] Research has found that to create a pleasant passenger environment, vehicle air conditioning systems are often kept running. When a fire occurs, the TCMS system shuts down the air conditioning system upon receiving a signal from the fire detector. Furthermore, the reliability of fire alarms decreases over time. Therefore, in the early stages of a fire, before the heat and smoke generated by the fire have activated the fire alarm, a properly functioning air conditioning system can alter the temperature and smoke distribution within the vehicle, potentially affecting passenger evacuation. Therefore, accurately studying the impact of a vehicle's air conditioning system's operating status on the evacuation process during a vehicle fire is a significant technical challenge.

[0056] Based on this, an embodiment of the present application provides a numerical simulation method for subway train fires to improve the accuracy and diversity of numerical simulations of subway train fires.

[0057] Please refer to Figure 1, which is a flow chart of a numerical simulation method for a subway train fire provided by an embodiment of the present application. As shown in Figure 1, the numerical simulation method provided by the embodiment of the present application includes:

[0058] S101, obtaining a front view and a top view corresponding to a subway car, and establishing an original three-dimensional model corresponding to the subway car according to the front view and the top view.

[0059] Regarding the above step S101, during the specific implementation, the front view and top view corresponding to the subway car are obtained, and the original three-dimensional model corresponding to the subway car is established in the three-dimensional mapping software based on the front view and top view corresponding to the subway car.

[0060] As an optional implementation, with respect to the above step S101, establishing the original three-dimensional model corresponding to the subway car according to the front view and the top view includes:

[0061] Step 1011: Determine the corresponding car size of the subway car according to the front view and the top view.

[0062] Here, car size refers to the length, width and height of the subway car.

[0063] Regarding step 1011, in a specific implementation, after obtaining the front view and top view of the subway car, the corresponding car dimensions of the subway car are determined based on the dimensional data of the subway car recorded in the front view and top view. As an example, this application uses the MP car of a certain type A subway train as the research object, and determines the car dimensions to be 22.80m×3.08m×2.10m based on the front view and top view of the subway car.

[0064] Step 1012: Determine the physical structure of the subway car based on the front view and the top view.

[0065] Regarding step 1012, during implementation, the physical structure of the subway car is determined based on the front view and the top view of the subway car. Continuing with the above embodiment, the present application determines, based on the front view and the top view, that the seats inside the subway car are arranged longitudinally against the wall, with five doors and four windows on each side. Furthermore, the air supply vents for the air conditioning system on the car roof are arranged sequentially along both sides of the car roof. Furthermore, a waste exhaust vent is provided on the car roof to utilize hot-pressed smoke exhaust.

[0066] Step 1013: Create an original three-dimensional model corresponding to the subway car according to the car size and the physical structure.

[0067] Regarding step 1013, during implementation, a corresponding original 3D model of the subway car is created in 3D mapping software based on the car's dimensions and physical structure. Specifically, how to create the original 3D model in 3D mapping software is described in detail in the prior art and will not be further elaborated here.

[0068] S102: Importing the original three-dimensional model into FDS software, and setting fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car.

[0069] It should be noted that FDS software is an open source program for numerical calculations of fires. FDS is suitable for describing low-speed, heat-driven gas flow problems. It uses numerical methods to solve the NS equations of buoyancy-driven low Mach number flow, and realizes the calculation of smoke flow and heat transfer during the fire process. It is used to study the spread characteristics of smoke inside the vehicle compartment after a fire under different air-conditioning modes (off, air-conditioning and ventilation).

[0070] Regarding the above step S102, during specific implementation, the original three-dimensional model is imported into the FDS software, and fire simulation parameters are set for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in a subway car.

[0071] As an optional implementation, with respect to step S102 above, setting fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car includes:

[0072] In the FDS software, the initial state of the flow field in the original three-dimensional model is set to a preset state, the temperature in the simulation area of ​​the original three-dimensional model and the ambient temperature outside the simulation area are both preset temperatures, the pressure in the original three-dimensional model is a preset pressure value, the preset position in the original three-dimensional model is the fire source position, the fire source size is a preset size, and the ignition mode of the fire source is a preset mode, so as to obtain the simulation model.

[0073] For the above steps, during specific implementation, the initial state of the flow field in the original three-dimensional model is set as a preset state in the FDS software. Here, as an example, the preset state can be set to static, and this application does not make any specific restrictions on this. In the FDS software, the temperature in the simulation area of ​​the original three-dimensional model and the ambient temperature outside the simulation area are set to preset temperatures. Here, as an example, the preset temperature can be set to 26°C. In the FDS software, the pressure in the original three-dimensional model is set to a preset pressure value. Here, as an example, the preset pressure value can be 1 standard atmosphere. In the FDS software, the preset position in the original three-dimensional model is set as the fire source position, the fire source size is the preset size, and the ignition mode of the fire source is the preset mode. Here, as an example, the preset position can be the middle of the subway car, the preset size can be 0.5m×0.5m, and the preset mode is the fifth ignition mode in the EU train fire protection standard EN45545-2013.

[0074] According to the embodiments provided herein, after a fire occurs, the spread of the combustion area and the flow of smoke are unsteady processes. Solving the governing equations requires the initial parameters of the flow field. As an example, assume the initial state of the flow field is static, the temperature within the simulation area and the outdoor ambient temperature are both 26°C, and the pressure is 1 standard atmosphere. Inert boundaries are used around the vehicle body, and open boundaries are used at the front and rear. This study uses the heat release rate per unit area (HRRPUA) to reflect the combustion of non-metallic materials within the vehicle compartment. The ignition point and heat release rate curves of the materials are referenced from test results of vehicle materials. Subway car fires present many uncertainties. The power of the fire source will affect the fire development process within the train compartment. Furthermore, the location of the fire source is also crucial, as the amount and combustion properties of combustible materials vary at different locations within the subway car. Therefore, the location and power of the fire source are important factors influencing the development of a vehicle fire. Current studies on subway car fires have chosen a fire source in the middle of the car. When the fire source is located in the middle of the car, the smoke generated can spread to both ends after impacting the car ceiling. Therefore, during the research process, this application also set the fire source location in the middle of the carriage, with a size of 0.5m x 0.5m. Due to the strong security measures implemented in subways, the probability of arson is relatively low. Therefore, this application refers to the fifth ignition mode of the European Union train fire protection standard EN45545-2013 to simulate the fire situation of the salute. This ignition mode is 75kW continuous output for two minutes, followed by 150kW continuous output for eight minutes.

[0075] Furthermore, in fire simulation, it is necessary to accurately simulate key parameters such as temperature distribution, spread, and heat release rate in the fire scene. Therefore, the simulation grid needs to be fine enough. The FDS software user guide gives an estimated value of the fire characteristic diameter D * :

[0076] Where: Q is the fire heat release rate; ρ ∞ is the environmental density; T ∞ is the ambient temperature; c p is the specific heat at constant pressure; g is the acceleration due to gravity.

[0077] From the above formula, we can know that the characteristic diameter of fire D * As the fire heat release rate Q increases, the fire calculation of the entire vehicle can be satisfied as long as the recommended grid size corresponding to the ignition source is maintained. Previous studies have shown that the calculation grid size is selected as 0.1D * When the power of the fire source is about 0.05mm, the simulation results under most fire source power conditions are consistent with the fire test results. Therefore, the final grid of this application is 0.06m×0.06m×0.06m at the middle car position of the calculation domain, and the grid size of the air domain in front and behind the car is 0.12m×0.12m×0.12m, with a total number of 3.24 million grids.

[0078] S103, for each air-conditioning operation mode of the air-conditioning system in the subway car, using the FDS software to perform numerical calculations on the simulation model under the air-conditioning operation mode, to obtain a curve of fire simulation data changing over time at different preset positions in the subway car under the air-conditioning operation mode, so as to evaluate the impact of using the air-conditioning operation mode on the evacuation of personnel when a fire occurs in the subway car based on the curve of fire simulation data changing over time.

[0079] Because the smoke flow after a fire in a subway car is a three-dimensional, unsteady, compressible, turbulent flow, this application uses FDS software to perform numerical simulations of vehicle fires. Regarding step S103 above, in specific implementation, for each air conditioning operation mode of the subway car's air conditioning system, numerical calculations are performed on the simulation model using FDS software under that air conditioning operation mode, resulting in a time-varying curve of the fire simulation data at different locations in the subway car under that air conditioning operation mode. Based on this time-varying curve of the fire simulation data, the impact of using that air conditioning operation mode on evacuation in the event of a fire in the subway car is evaluated.

[0080] Among them, the air-conditioning operation mode includes an off mode, an air-conditioning mode and a ventilation mode, and the fire simulation data includes the contact temperature at the characteristic height of the personnel in the subway car, the visibility at the characteristic height of the personnel, the temperature of the subway car roof and the concentration of toxic gases at the characteristic height of the human body. Specifically, after a fire occurs in a vehicle, the combustion of combustible materials produces a large amount of heat, smoke, unburned carbon black particles and toxic decomposition products, etc. These products will seriously affect the evacuation of personnel. When the smoke drops to the characteristic height of the personnel, the visibility drops sharply, and the high-temperature smoke and the toxic components in the smoke will directly cause harm to the human body. Combined with the average height of an adult and taking into account that the human body will bend slightly during the evacuation process, the characteristic height of the personnel defined in this application is 1.5m. The preset positions here can include 1 meter from the end of the car, 7m from the end of the car, 13m from the end of the car and 21m from the end of the car, and this application does not make specific restrictions on this.

[0081] The evaluation indicator for the impact of high-temperature air on the human body is the heat load value borne by the human surface. Breathing and contact with overheated air can cause heatstroke and skin burns. The safety standard for contact temperature selected in this application is: the contact temperature at the characteristic height of personnel should be less than 60°C. Visibility is one of the important factors affecting personnel evacuation. When the smoke layer drops to the height of personnel, the walking speed of personnel will drop significantly under low visibility conditions. The safety standard for personnel visibility selected in this application is: visibility at the characteristic height of personnel should be greater than 10m. The large amount of heat radiated by flames and high-temperature smoke can cause high-temperature radiation damage to the human body. When the human skin temperature reaches around 45°C, it will cause pain. When the human body inhales hot smoke at a temperature of 150°C or higher, it will cause internal burns. Studies have found that in a fire environment, the maximum thermal radiation tolerance of the human body to high-temperature smoke and fire sources is 2.5kW / m2. Therefore, as long as this range is not exceeded, evacuated personnel will not be burned by high-temperature radiation. Because the hot smoke generated by a vehicle fire accumulates on the top of the car, the temperature at the top of the car is the highest. If the temperature of the smoke there exceeds 150°C and is inhaled by the human body, it will cause irreversible damage. The judgment basis selected in this application is: the smoke temperature under the roof should be less than 150°C. The harmful gases produced by the fire include carbon monoxide (CO), sulfur dioxide (SO2), hydrogen sulfide (H2S), etc. Among them, carbon monoxide produced by incomplete combustion of carbon-containing substances is very common in fires. It is one of the most toxic and harmful gases that poses the greatest threat to the safety of crowd evacuation. The judgment basis selected in this application is: the CO concentration at the characteristic height of personnel should be lower than 1150ppm.

[0082] As an optional implementation, before performing numerical calculation on the simulation model in the air-conditioning operation mode using the FDS software, the numerical simulation method further includes:

[0083] Based on a preset fire occurrence time point and a preset running state corresponding to the train to which the subway car belongs, an evacuation time point for opening the car door to evacuate people is determined when a fire occurs in the subway car.

[0084] It should be noted that the preset fire occurrence time refers to the time when the simulation model begins numerical calculations for the fire simulation. The "Metro Safety Evacuation Regulations" stipulate that after a fire occurs, the train should proceed to the next station for evacuation. Therefore, this application assumes that the preset fire occurrence time is the time when the train has just left the station.

[0085] Regarding the above steps, during specific implementation, the evacuation time point for opening the car doors and evacuating passengers when a fire occurs in the subway car is determined based on the preset fire occurrence time point and the preset operating status corresponding to the train to which the subway car belongs. Please refer to Figure 2, which is a schematic diagram of a train operating status change provided in an embodiment of the present application. Continuing with the above embodiment, the preset fire occurrence time point is when the train has just left the station and the vehicle needs to travel to the next station. The train operating status change is shown in Figure 2. The train travels a distance of 2 km and arrives at the next station in 109 seconds. Therefore, the evacuation time point is 109 seconds after the preset fire occurrence time point, that is, the single-side door is opened to evacuate passengers.

[0086] As an optional implementation, with respect to the above step S103, when the air conditioning operation mode is the off mode, performing numerical calculations on the simulation model in the air conditioning operation mode using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air conditioning operation mode includes:

[0087] A: The air conditioning system in the simulation model is set to a closed state based on the closed mode.

[0088] Regarding the above step A, during specific implementation, since the current air-conditioning operation mode is the off mode, the air-conditioning system in the simulation model is set to the off state.

[0089] B: Taking the preset fire occurrence time point as the starting point, use the FDS software to perform fire numerical simulation on the simulation model to determine the fire simulation data for each preset location in the subway car at each time point within the first simulation time period.

[0090] The first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point.

[0091] Regarding step B above, during implementation, numerical fire simulation is performed on the simulation model using FDS software, starting at the preset fire occurrence time. Fire simulation data is then determined for each preset location in the subway car at each time point during the first simulation period. Specifically, the fire simulation data includes the contact temperature at a characteristic occupant height within the subway car, visibility at a characteristic occupant height, the temperature of the subway car ceiling, and the concentration of toxic gases at a characteristic human height.

[0092] C: Assume that the car door in the simulation model is open, use the FDS software to perform fire numerical simulation on the simulation model, and determine the fire simulation data of each preset position in the subway car at each time point in the second simulation time period.

[0093] The second simulation time period is the time period from the evacuation time point to the preset fire end time point.

[0094] When the simulation reaches the evacuation time point, the car doors must be opened to facilitate evacuation. Regarding step C above, in the specific implementation, the car doors in the simulation model are set to be open. Fire numerical simulation is performed on the simulation model using FDS software to determine the fire simulation data for each preset location in the subway car at each time point during the second simulation time period.

[0095] D: Generate a time-varying curve of the fire simulation data at different preset positions in the subway car based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

[0096] For the above step D, during the specific implementation, a curve of the change of fire simulation data over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

[0097] As an optional implementation, with respect to the above step S103, when the air conditioning operation mode is the air conditioning mode, performing numerical calculations on the simulation model in the air conditioning operation mode using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air conditioning operation mode includes:

[0098] a: Based on the air-conditioning mode, the air supply temperature of the air-conditioning system in the simulation model is set to a first preset temperature, and the total air supply volume of the air-conditioning system is set to a first preset air supply volume.

[0099] Here, the first preset temperature can be 20°C, and the first preset air volume can be 10000m3 / h, this application does not make any specific limitation on this.

[0100] Regarding step a above, during specific implementation, since the current air conditioning operation mode is the air conditioning mode, the air supply temperature of the air conditioning system in the simulation model is set to the first preset temperature, and the total air supply volume of the air conditioning system is set to the first preset air supply volume.

[0101] b: Taking the preset fire occurrence time point as the starting point, use the FDS software to perform fire numerical simulation on the simulation model to determine the fire simulation data for each preset location in the subway car at each time point within a first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point.

[0102] c: Assume that the car doors in the simulation model are open, use the FDS software to perform fire numerical simulation on the simulation model, and determine the fire simulation data for each preset location in the subway car at each time point within a second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point.

[0103] d: Based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data of each preset position at each time point in the second simulation time period, a curve of the fire simulation data changing over time at different preset positions in the subway car is generated.

[0104] Here, the description of the above steps b-d can refer to the description of the above steps B-D, and can achieve the same technical effect, which will not be repeated here.

[0105] As an optional implementation, with respect to the above step S103, when the air-conditioning operation mode is the ventilation mode, performing numerical calculations on the simulation model in the air-conditioning operation mode using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air-conditioning operation mode includes:

[0106] (1): Based on the ventilation mode, the air supply temperature of the air-conditioning system in the simulation model is set to a second preset temperature, and the total air supply volume of the air-conditioning system is set to a second preset air supply volume.

[0107] Here, the second preset temperature can be 40°C, and the second preset air volume can be 4000m 3 / h, this application does not make any specific limitation on this.

[0108] Regarding the above step (1), during the specific implementation, since the current air-conditioning operation mode is ventilation mode, the air supply temperature of the air-conditioning system in the simulation model is set to the second preset temperature, and the total air supply volume of the air-conditioning system is set to the second preset air supply volume.

[0109] (2): Taking the preset fire occurrence time point as the starting point, the FDS software is used to perform fire numerical simulation on the simulation model to determine the fire simulation data of each preset position in the subway car at each time point within the first simulation time period; wherein, the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point.

[0110] (3): Assume that the car door in the simulation model is open, use the FDS software to perform fire numerical simulation on the simulation model, and determine the fire simulation data of each preset position in the subway car at each time point within the second simulation time period; wherein, the second simulation time period is the time period from the evacuation time point to the preset fire end time point.

[0111] (4): Based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period, a curve of the fire simulation data changing over time at different preset positions in the subway car is generated.

[0112] Here, the description of the above steps (2) to (4) can refer to the description of the above steps B to D, and can achieve the same technical effects, so they will not be repeated here.

[0113] According to the embodiment provided by this application, as an example, when a fire occurs in the middle of a carriage, passengers in the starting carriage will evacuate to the carriages at both ends. Therefore, the temperature and visibility at both ends of the carriage are crucial for passenger evacuation. After obtaining multiple fire simulation data over time curves in the above step S103, this application will analyze the impact of the air conditioning system on the evacuation process by comparing the contact temperature at the characteristic height of the personnel, visibility, temperature under the carriage roof, and toxic gas concentration under different air conditioning operating modes. From the temperature distribution cloud diagram of the car section at different times generated by the method provided in the above embodiment of the present application, it can be seen that when the air conditioning system is turned off, the smoke in the car hits the top plate and spreads to both sides of the car and forms a stable smoke layer in the car; when the vehicle air conditioning system is in air conditioning or ventilation mode, the air flow blown out of the air outlet in the car destroys the smoke layer on the top of the car, causing the high-temperature smoke to sink in the middle of the car, and the temperature on both sides of the car rises significantly; after the car door is opened at 109s, the smoke accumulated in the car overflows through the door, and the thickness of the smoke layer is significantly reduced; since the air supply volume of the air conditioning mode is greater than that of the ventilation mode, it can be seen from the comparison of the temperature distribution at the same time that the smoke deposition effect caused by the air conditioning mode is greater than that of the ventilation mode. In summary: the temperature at the top of the car is the highest in all three air conditioning operating modes, and the temperature at the characteristic height of the human body is less than 60°C, which has little impact on the evacuation of personnel; turning on the air conditioning or ventilation mode can effectively reduce the contact temperature at both ends of the car, which is conducive to the evacuation of personnel.

[0114] Please refer to Figures 3(a) to 3(d). Figure 3(a) is a graph showing how visibility at a characteristic height of a human body in a car 1m away from the end of the car, provided in an embodiment of the present application. Figure 3(b) is a graph showing how visibility at a characteristic height of a human body in a car 7m away from the end of the car, provided in an embodiment of the present application. Figure 3(c) is a graph showing how visibility at a characteristic height of a human body in a car 13m away from the end of the car, provided in an embodiment of the present application. Figure 3(d) is a graph showing how visibility at a characteristic height of a human body in a car 21m away from the end of the car, provided in an embodiment of the present application. As shown in Figures 3(a)-3(d), visibility at characteristic human heights within the vehicle cabin exhibits a distribution with low visibility in the middle and high visibility at both ends. Comparing Figures 3(a) and 3(d), we can see that when smoke reaches the ends of the cabin, it accumulates and sinks there. Therefore, when the air conditioning system is off, visibility at the ends is lower than in the middle. When the vehicle's air conditioning system is in air conditioning or ventilation mode, visibility at the ends of the cabin significantly improves. Comparing Figures 3(b) and 3(c), we can see that when the air conditioning is on, visibility near the fire source (11 meters from the end) is poor. The air conditioning cools the smoke near the fire source, causing the mixed gas to sink and reduce visibility at that location. However, in ventilation mode, due to the lower air volume and higher air temperature, the mixed smoke does not settle significantly and can be quickly discharged through the doors to the outside when the vehicle doors are opened. In summary: when the vehicle's air-conditioning system is in air-conditioning or ventilation mode, although the smoke in the middle of the car will sink and reduce visibility, it can effectively improve visibility at both ends of the car, which is conducive to personnel evacuation.

[0115] Please refer to Figures 4(a)-4(d). Figure 4(a) is a graph showing the temperature variation over time under the ceiling of a vehicle compartment 1m from the end of the vehicle compartment, according to an embodiment of the present application. Figure 4(b) is a graph showing the temperature variation over time under the ceiling of a vehicle compartment 7m from the end of the vehicle compartment, according to an embodiment of the present application. Figure 4(c) is a graph showing the temperature variation over time under the ceiling of a vehicle compartment 14m from the end of the vehicle compartment, according to an embodiment of the present application. Figure 4(d) is a graph showing the temperature variation over time under the ceiling of a vehicle compartment 21m from the end of the vehicle compartment, according to an embodiment of the present application. As shown in Figures 4(a)-4(d), the temperature of the smoke layer formed in the upper part of the vehicle compartment gradually increases as the fire progresses, with the temperature at the ends of the vehicle being lower than that in the middle of the vehicle compartment. After 109 seconds of opening the vehicle door, a large amount of smoke overflows, and the temperature under the ceiling of the vehicle compartment drops significantly. When the vehicle air conditioning system is in air conditioning or ventilation mode, the airflow entering the vehicle compartment through the air supply port mixes with the high-temperature smoke, significantly reducing the temperature under the ceiling of the vehicle compartment. The air conditioning mode is more effective than the ventilation mode. In the middle of the car, near the fire source, ventilation mode's low air volume and high temperature didn't significantly cool the area. Air conditioning mode, with its high air volume and low temperature, also had a poor cooling effect. In summary, turning on the vehicle's air conditioning system effectively lowered the temperature below the ceiling at both ends of the car, facilitating passenger evacuation.

[0116] Please refer to Figures 5(a) to 5(d). Figure 5(a) is a graph showing the change of toxic gas concentration over time at a characteristic height of a human body in a carriage 1m away from the end of the carriage provided in an embodiment of the present application. Figure 5(b) is a graph showing the change of toxic gas concentration over time at a characteristic height of a human body in a carriage 7m away from the end of the carriage provided in an embodiment of the present application. Figure 5(c) is a graph showing the change of toxic gas concentration over time at a characteristic height of a human body in a carriage 15m away from the end of the carriage provided in an embodiment of the present application. Figure 5(d) is a graph showing the change of toxic gas concentration over time at a characteristic height of a human body in a carriage 21m away from the end of the carriage provided in an embodiment of the present application. As shown in Figures 5(a)-5(d), the high-temperature smoke generated by the fire spread to the ends of the car, accumulated, and sank, resulting in significantly higher carbon monoxide concentrations at both ends than in the middle. After the door was opened 109 seconds later, a large amount of smoke escaped, significantly reducing the carbon monoxide concentration in the car. When the vehicle's air conditioning system was in air conditioning or ventilation mode, the airflow entering the car through the air vents effectively diluted the smoke in the lower part of the car, significantly reducing the CO concentration at both ends of the car. However, when the vehicle was in the middle of the car, the airflow entering the car through the air vents entrained some smoke to the lower part of the car, resulting in a higher carbon monoxide concentration in the middle than when the air conditioning was turned off. While the air conditioning mode effectively reduced the CO concentration at both ends of the car due to its higher air volume, it also increased the CO concentration in the middle. In summary, turning on the vehicle's air conditioning system effectively reduced the CO concentration at the human body height at both ends of the car, facilitating passenger evacuation.

[0117] The numerical simulation method for subway train fire provided in an embodiment of the present application is first used to obtain a front view and a top view corresponding to a subway car, and establish an original three-dimensional model corresponding to the subway car based on the front view and the top view; then, the original three-dimensional model is imported into FDS software, and fire simulation parameters are set for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car; finally, for each air-conditioning operation mode of the air-conditioning system in the subway car, the simulation model is numerically calculated using the FDS software under the air-conditioning operation mode to obtain a time-varying curve of fire simulation data at different preset positions in the subway car under the air-conditioning operation mode, so as to evaluate the impact of using the air-conditioning operation mode on the evacuation of personnel when a fire occurs in the subway car based on the time-varying curve of the fire simulation data.

[0118] This application uses numerical simulation methods to calculate the temperature, visibility, toxic gas concentration, and temperature under the car roof at characteristic heights of occupants in subway cars under different air-conditioning operation modes after a fire breaks out at a typical fire location in the car. This improves the accuracy and diversity of numerical simulations of subway train fires and provides a data basis for analyzing the impact of air-conditioning system operation on the evacuation process.

[0119] Please refer to FIG6 , which is a schematic diagram of the structure of a numerical simulation device for subway train fire provided in an embodiment of the present application. As shown in FIG6 , the numerical simulation device 600 includes:

[0120] A three-dimensional model building module 601 is used to obtain a front view and a top view corresponding to a subway car, and to build an original three-dimensional model corresponding to the subway car based on the front view and the top view;

[0121] A simulation model building module 602 is configured to import the original three-dimensional model into FDS software and set fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car;

[0122] The fire numerical simulation module 603 is used to perform numerical calculations on the simulation model in the FDS software for each air-conditioning operation mode of the air-conditioning system in the subway car under the air-conditioning operation mode, thereby obtaining a time-varying curve of the fire simulation data at different preset positions in the subway car under the air-conditioning operation mode, so as to evaluate the impact of the air-conditioning operation mode on the evacuation of personnel when a fire occurs in the subway car based on the time-varying curve of the fire simulation data; wherein the air-conditioning operation modes include the off mode, the air-conditioning mode, and the ventilation mode, and the fire simulation data include the contact temperature at the characteristic height of personnel in the subway car, the visibility at the characteristic height of personnel, and the temperature of the subway car roof.

[0123] Furthermore, when the three-dimensional model building module 601 is used to build the original three-dimensional model corresponding to the subway car according to the front view and the top view, the three-dimensional model building module 601 is further used to:

[0124] Determining the size of the subway car according to the front view and the top view;

[0125] determining the physical structure of the subway car according to the front view and the top view;

[0126] An original three-dimensional model corresponding to the subway car is established according to the car size and the physical structure.

[0127] Furthermore, when the simulation model establishment module 602 is used to set fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car, the simulation model establishment module 602 is further used to:

[0128] In the FDS software, the initial state of the flow field in the original three-dimensional model is set to a preset state, the temperature in the simulation area of ​​the original three-dimensional model and the ambient temperature outside the simulation area are both preset temperatures, the pressure in the original three-dimensional model is a preset pressure value, the preset position in the original three-dimensional model is the fire source position, the fire source size is a preset size, and the ignition mode of the fire source is a preset mode, so as to obtain the simulation model.

[0129] Furthermore, the numerical simulation device 600 further includes an evacuation time point determination module. Before performing numerical calculations on the simulation model in the air-conditioning operation mode using the FDS software, the evacuation time point determination module is configured to:

[0130] Based on a preset fire occurrence time point and a preset running state corresponding to the train to which the subway car belongs, an evacuation time point for opening the car door to evacuate people is determined when a fire occurs in the subway car.

[0131] Furthermore, when the air conditioning operation mode is the off mode, the fire numerical simulation module 603 is used to perform numerical calculations on the simulation model in the air conditioning operation mode using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air conditioning operation mode. The fire numerical simulation module 603 is also used to:

[0132] Setting the air conditioning system in the simulation model to a closed state based on the closed mode;

[0133] Taking the preset fire occurrence time point as a starting point, using the FDS software to perform fire numerical simulation on the simulation model, and determining fire simulation data for each preset location in the subway car at each time point within a first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point;

[0134] Assuming that the car door in the simulation model is open, using the FDS software to perform a fire numerical simulation on the simulation model, and determining the fire simulation data at each preset location in the subway car at each time point within a second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point;

[0135] A curve of fire simulation data changing over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

[0136] Furthermore, when the air conditioning operation mode is the air conditioning mode, the fire numerical simulation module 603 is used to perform numerical calculations on the simulation model in the air conditioning operation mode using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air conditioning operation mode. The fire numerical simulation module 603 is also used to:

[0137] Based on the air conditioning mode, the air supply temperature of the air conditioning system in the simulation model is set to a first preset temperature, and the total air supply volume of the air conditioning system is set to a first preset air supply volume;

[0138] Taking the preset fire occurrence time point as a starting point, using the FDS software to perform fire numerical simulation on the simulation model, and determining fire simulation data for each preset location in the subway car at each time point within a first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point;

[0139] Assuming that the car door in the simulation model is open, using the FDS software to perform a fire numerical simulation on the simulation model, and determining the fire simulation data at each preset location in the subway car at each time point within a second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point;

[0140] A curve of fire simulation data changing over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

[0141] Furthermore, when the air conditioning operation mode is the ventilation mode, the fire numerical simulation module 603 is used to perform numerical calculations on the simulation model in the air conditioning operation mode using the FDS software to obtain a curve of fire simulation data changing over time at different preset positions in the subway car in the air conditioning operation mode. The fire numerical simulation module 603 is also used to:

[0142] Based on the ventilation mode, the air supply temperature of the air conditioning system in the simulation model is set to a second preset temperature, and the total air supply volume of the air conditioning system is set to a second preset air supply volume;

[0143] Taking the preset fire occurrence time point as a starting point, using the FDS software to perform fire numerical simulation on the simulation model, and determining fire simulation data for each preset location in the subway car at each time point within a first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point;

[0144] Assuming that the car door in the simulation model is open, using the FDS software to perform a fire numerical simulation on the simulation model, and determining the fire simulation data at each preset location in the subway car at each time point within a second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point;

[0145] A curve of fire simulation data changing over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

[0146] Please refer to Figure 7 , which is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. As shown in Figure 7 , the electronic device 700 includes a processor 710 , a memory 720 , and a bus 730 .

[0147] The memory 720 stores machine-readable instructions executable by the processor 710. When the electronic device 700 is running, the processor 710 communicates with the memory 720 via the bus 730. When the machine-readable instructions are executed by the processor 710, the steps of the numerical simulation method for subway train fire in the method embodiment shown in Figure 1 above can be executed. The specific implementation method can be found in the method embodiment and will not be repeated here.

[0148] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program can execute the steps of the numerical simulation method for subway train fire in the method embodiment shown in FIG1 above. The specific implementation method can be found in the method embodiment and will not be repeated here.

[0149] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0150] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. There may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed may be through some communication interface, indirect coupling or communication connection of devices or units, which may be electrical, mechanical or other forms.

[0151] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0152] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0153] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0154] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above-mentioned embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-mentioned embodiments within the technical scope disclosed in the present application, or perform equivalent replacements for some of the technical features thereof. These modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A numerical simulation method for subway train fire, characterized in that: The numerical simulation method comprises: Acquire a front view and a top view corresponding to the subway car, and establish an original three-dimensional model corresponding to the subway car according to the front view and the top view; Importing the original three-dimensional model into FDS software, and setting fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car; For each air-conditioning operation mode of the air-conditioning system in the subway car, the simulation model in the FDS software is numerically calculated under the air-conditioning operation mode to obtain a curve of fire simulation data changing over time at different preset positions in the subway car under the air-conditioning operation mode, so as to evaluate the impact of the air-conditioning operation mode on the evacuation of personnel when a fire occurs in the subway car based on the curve of fire simulation data changing over time; wherein, the air-conditioning operation modes include an off mode, an air-conditioning mode and a ventilation mode, and the fire simulation data include the contact temperature at the characteristic height of personnel in the subway car, the visibility at the characteristic height of personnel and the temperature of the roof of the subway car.

2. The numerical simulation method according to claim 1, characterized in that: The step of establishing the original three-dimensional model corresponding to the subway car according to the front view and the top view includes: Determine the size of the subway car according to the front view and the top view; Determining the physical structure of the subway car according to the front view and the top view; An original three-dimensional model corresponding to the subway car is established according to the car size and the physical structure.

3. The numerical simulation method according to claim 1, characterized in that: The setting of fire simulation parameters for the original three-dimensional model in the FDS software to generate a simulation model for simulating a fire in the subway car includes: In the FDS software, the initial state of the flow field in the original three-dimensional model is set to a preset state, the temperature in the simulation area in the original three-dimensional model and the ambient temperature outside the simulation area are both preset temperatures, the pressure in the original three-dimensional model is a preset pressure value, the preset position in the original three-dimensional model is the fire source position, the fire source size is a preset size, and the ignition mode of the fire source is a preset mode, so as to obtain the simulation model.

4. The numerical simulation method according to claim 1, characterized in that: Before performing numerical calculation on the simulation model in the air-conditioning operation mode using the FDS software, the numerical simulation method further includes: Based on a preset fire occurrence time point and a preset running state corresponding to the train to which the subway car belongs, an evacuation time point for opening the car door to evacuate people is determined when a fire occurs in the subway car.

5. The numerical simulation method according to claim 4, characterized in that: When the air-conditioning operation mode is the off mode, the numerical calculation of the simulation model in the air-conditioning operation mode is performed using the FDS software to obtain the curve of the change of fire simulation data over time at different preset positions in the subway car in the air-conditioning operation mode, including: Setting the air conditioning system in the simulation model to a closed state based on the closed mode; Taking the preset fire occurrence time point as the starting point, the FDS software is used to perform fire numerical simulation on the simulation model to determine the fire simulation data at each preset position in the subway car at each time point within the first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point; The car door in the simulation model is set to be open, and the fire numerical simulation is performed on the simulation model using the FDS software to determine the fire simulation data of each preset position in the subway car at each time point in the second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point; A curve of the change of fire simulation data over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

6. The numerical simulation method according to claim 4, characterized in that: When the air-conditioning operation mode is the air-conditioning mode, the numerical calculation of the simulation model in the air-conditioning operation mode is performed using the FDS software to obtain the curve of the change of fire simulation data over time at different preset positions in the subway car in the air-conditioning operation mode, including: Based on the air conditioning mode, setting the air supply temperature of the air conditioning system in the simulation model to a first preset temperature, and setting the total air supply volume of the air conditioning system to a first preset air supply volume; Taking the preset fire occurrence time point as the starting point, the FDS software is used to perform fire numerical simulation on the simulation model to determine the fire simulation data at each preset position in the subway car at each time point within the first simulation time period; wherein the first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point; The car door in the simulation model is set to be open, and the fire numerical simulation is performed on the simulation model using the FDS software to determine the fire simulation data of each preset position in the subway car at each time point in the second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point; A curve of the change of fire simulation data over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

7. The numerical simulation method according to claim 4, characterized in that: When the air-conditioning operation mode is the ventilation mode, the numerical calculation of the simulation model in the air-conditioning operation mode is performed using the FDS software to obtain the curve of the change of fire simulation data over time at different preset positions in the subway car in the air-conditioning operation mode, including: Based on the ventilation mode, setting the air supply temperature of the air conditioning system in the simulation model to a second preset temperature, and setting the total air supply volume of the air conditioning system to a second preset air supply volume; Taking the preset fire occurrence time point as the starting point, the FDS software is used to perform fire numerical simulation on the simulation model to determine the fire simulation data of each preset position in the subway car at each time point in the first simulation time period; wherein, The first simulation time period is the time period from the preset fire occurrence time point to the evacuation time point; The car door in the simulation model is set to be open, and the fire numerical simulation is performed on the simulation model using the FDS software to determine the fire simulation data of each preset position in the subway car at each time point in the second simulation time period; wherein the second simulation time period is the time period from the evacuation time point to the preset fire end time point; A curve of the change of fire simulation data over time at different preset positions in the subway car is generated based on the fire simulation data of each preset position at each time point in the first simulation time period and the fire simulation data at each time point in the second simulation time period.

8. A numerical simulation device for subway train fire, characterized in that: The numerical simulation device comprises: A three-dimensional model building module, used to obtain a front view and a top view corresponding to the subway car, and to build an original three-dimensional model corresponding to the subway car according to the front view and the top view; A simulation model building module, used for importing the original three-dimensional model into the FDS software, and setting fire simulation parameters for the original three-dimensional model in the FDS software, so as to generate a simulation model for simulating a fire in the subway car; The fire numerical simulation module is used for performing numerical calculations on the simulation model in the air-conditioning operation mode for each air-conditioning operation mode of the air-conditioning system in the subway car by using the FDS software, so as to obtain a curve of fire simulation data changing over time at different preset positions in the subway car under the air-conditioning operation mode, so as to evaluate the influence of the air-conditioning operation mode on the evacuation of personnel when a fire occurs in the subway car based on the curve of fire simulation data changing over time; wherein the air-conditioning operation mode includes an off mode, an air-conditioning mode and a ventilation mode, and the fire simulation data includes the contact temperature at the characteristic height of personnel in the subway car, the visibility at the characteristic height of personnel and the temperature of the roof of the subway car.

9. An electronic device, characterized in that: include: A processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate through the bus, and the machine-readable instructions are executed by the processor to execute the steps of the numerical simulation method for subway train fire as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the numerical simulation method for subway train fire according to any one of claims 1 to 7 are executed.

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