Analysis Method for Virus Transmission Inside Civil Aviation Passenger Aircraft

Abstract

The present invention discloses a method for analyzing virus transmission in the cabin of a civil airliner, including collecting parameters of the civil airliner, constructing a physical model of the cabin in a selected space using 3D modeling software; performing mesh division on the constructed physical model of the cabin; simulating the physically modeled cabin after mesh division; determining the simulated path of virus diffusion, as well as the velocity field and concentration field of diffusion according to the simulation results; calculating the probability of infection risk for passengers in the cabin under different states of the personalized ventilation outlet above the infected passenger based on the mathematical model of virus transmission in the cabin of a civil airliner. The present invention provides suggestions for flight crew and passengers to reasonably arrange cabin activities and use personal protective equipment, reduce the infection risk of other passengers, isolate infected persons as much as possible, block virus transmission, and is of great significance to the physical health of passengers and flight crew.

Description

Technical Field

[0001] The present invention relates to a method for analyzing virus transmission in the cabin of a civil airliner, and particularly to a research method for virus transmission in the cabin of a civil airliner based on a CFD model. Background Art

[0002] With the rapid development of the world economy, more and more passengers choose to travel by air. During the flight of a civil airliner, the cabin is a closed environment, and passengers and crew members are exposed to an environment with a relatively high population density. The air flow is mainly achieved by the air conditioning ventilation system. When a passenger carrying a virus takes a plane, the virus adheres to the surface of objects or directly enters the air with breathing, saliva, and mucus. A healthy person may be infected by touching these contaminated surfaces or inhaling the virus.

[0003] The COVID-19 virus particles can be considered as a coronavirus different from the SARS virus, with a particle size of about 60 - 140 nm in the air, belonging to inhalable ultrafine particles, slightly smaller than the 80 - 220 nm particle size of the SARS virus. Some studies have shown that in relatively enclosed spaces and specific places, the COVID-19 virus can be transmitted in the form of aerosols. Since the cabin of a civil airliner is small in space and crowded with people, studying the method of virus transmission and diffusion in the cabin of a civil airliner is of great significance for protecting the health of passengers and crew members.

[0004] Since the spread of COVID-19, SARS, and several influenza incidents through civil airliners, the research on cross-transmission of germs in relatively enclosed environments has become increasingly important. Viruses can be carried by infected passengers on a plane from one city and transmitted to passengers on the same plane and people in another city. Research has shown that the cabin of a civil airliner is a suitable environment for the transmission of pathogens carried by passengers or crew members. The main ways and routes of virus transmission in the cabin include direct contact transmission, indirect contact transmission, and air transmission. The main methods for studying the spread and diffusion of viruses in the cabin include simulation experiment measurement methods, CFD numerical simulation methods, and probability analysis methods.

[0005] CFD has unique advantages such as low cost, high speed, complete data, and the ability to simulate various different working conditions, and has gradually gained people's favor. Research by Hao Lei et al. has shown that during short-haul flights, the exposure rate of aisle passengers is relatively high. Wei Yan et al. used a combination of simulation experiments and CFD numerical simulations to study the transmission characteristics of air pollutants in an aircraft cabin. The location of the pollution source has an important impact on the transmission of pollutants in the aircraft cabin.

[0006] Domestic scholars have conducted very little research in this area. Examples have proven that pollutants such as viruses in the cabin can spread within the aircraft cabin. These viruses have extremely small particle sizes and belong to inhalable particulate matter, with extremely strong transmission characteristics and a great impact on the health of the human population. Therefore, it is very necessary to invent a research method for virus transmission in the cabin of civil airliners based on the CFD model. Summary of the Invention

[0007] In order to overcome the defects existing in the prior art, the present invention aims to provide an analysis method for virus transmission in the cabin of civil airliners based on the CFD model.

[0008] The present invention adopts the following technical solutions. Provide an analysis method for virus transmission in the cabin of civil airliners, including the following steps:

[0009] Collect the parameters of civil airliners and use 3D modeling software to construct a physical model of the cabin in the selected space;

[0010] Perform mesh division on the constructed physical model of the cabin; simulate the mesh-divided physical model of the cabin; determine the simulated path of virus diffusion, as well as the velocity field and concentration field of diffusion according to the simulation results;

[0011] Based on the mathematical model of virus transmission in the cabin of civil airliners, calculate the infection risk probability of passengers in the cabin under different states of the personalized ventilation openings above the sick passengers.

[0012] Further, the parameters of the civil airliner include the overall dimensions of the cabin exterior, internal seats, human body dimensions, entrance and exit positions, the number of entrances and exits, and the dimensions of the entrances and exits.

[0013] Further, the simulation of the mesh-divided physical model of the cabin specifically includes the following steps:

[0014] Import the divided mesh into the FLUENT software for mesh inspection. If the mesh volume is negative, re-divide the mesh; set the turbulence model and select the RNG k-ε model; set the boundary conditions for the entrance and exit velocity, flow rate, and temperature; select the number of iterations and obtain the simulation results when the results no longer converge.

[0015] Further, the mathematical model formula for virus transmission in the cabin of civil airliners is as follows:

[0016]

[0017] Among them, P is the infection probability; D is the number of infected people; S is the number of susceptible people; I is the number of sick people; q is the virus unit release rate; p is the lung ventilation rate; Q is the cabin ventilation volume; α iThe i-th degree of opening of the personalized ventilation duct above the seat of the sick passenger; Q0 is the maximum ventilation volume of the personalized ventilation duct above the passenger seat, and t is the exposure time.

[0018] Furthermore, the degree of opening α of the personalized ventilation duct above the seat of the sick passenger i is expressed as: α i ={α1, α2, α3}, where α1 represents not opened, α2 represents opened at a specific ratio, and α3 represents fully opened.

[0019] Furthermore, the method further includes: by setting the moving mesh size and the moving speeds of the passengers and crew members in the cabin, analyzing the influence of the activities of the passengers in the cabin and the movement of the cabin services on the virus transmission in the cabin under unsteady conditions.

[0020] The beneficial technical effects achieved by the present invention:

[0021] The present invention studies the analysis method of virus transmission and diffusion in the cabin of a civil airliner, explores the virus diffusion situation when the virus source is at different positions in the cabin, and the virus diffusion situation when people move in the cabin, and visualizes the virus transmission route in the cabin of a civil airliner by using the method of numerical simulation.

[0022] The present invention can provide treatment suggestions for the crew members and airline management personnel when there are virus transmission events such as COVID-19 and SARS in the cabin, take appropriate measures to reduce the exposure risk of passengers and crew members, and contribute to the scientific protection of passengers and crew members in the cabin of a civil airliner and the prevention and control of the epidemic of infectious diseases. Description of the Drawings

[0023] Figure 1 is the basic process structure diagram of the embodiment of the present invention;

[0024] Figure 2 is the front view of the physical model of the 7th row of the A320 cabin of the embodiment of the present invention;

[0025] Figure 3 is the side view of the physical model of the 7th row of the A320 cabin of the embodiment of the present invention;

[0026] Figure 4 is the top view of the physical model of the 7th row of the A320 cabin of the embodiment of the present invention;

[0027] Figure 5 is the front view of the mesh division of the 7th row of the A320 cabin model of the embodiment of the present invention;

[0028] Figure 6 is the side view of the mesh division of the 7th row of the A320 cabin model of the embodiment of the present invention;

[0029] Figure 7It is a top view of the mesh division of the 7-row A320 cabin model in the embodiment of the present invention. Detailed implementation manners

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to embodiments. It should be clear that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] Embodiment: The method for analyzing virus transmission in a civil aviation airliner cabin provided in this embodiment has implementation steps as shown in the appendix Figure 1 , including the following steps carried out in sequence:

[0032] Step S1, construction of a physical model of a civil aviation airliner cabin.

[0033] The interior of the cabin is simplified to a certain extent, and only the interior space of the cabin overhead bin is retained. Since the full-size cabin model has a large number of units and a large number of subsequent required meshes, and the Civil Aviation Administration of China stipulates that when public health safety incidents such as virus transmission occur in the civil aviation airliner cabin, the passengers in the front and rear three rows should be isolated. Therefore, for the convenience of calculation, the interior of the cabin is simplified to a certain extent in this embodiment, and a periodic boundary condition is used to construct a 7-row cabin physical model.

[0034] In this embodiment, the overall dimensions of the 7-row physical model (length 6.3 m, width 3.7 m, height 2.26 m) and the positions and dimensions of the overhead bin air supply outlets, ceiling air supply outlets and air outlets are designed according to the dimensions of the A320 cabin, and a *.IGS file is output, as shown in Figure 2 、 3 、4.

[0035] In this embodiment, the Solidworks modeling software is used to construct the physical model of the cabin. In other embodiments, other modeling software such as CAD and UG can also be used for modeling.

[0036] Step S2, in this embodiment, the ICEM CFD preprocessor is used for mesh division of the physical model.

[0037] Step S201, first, a detailed understanding of the characteristics, principles and implementation processes of the CFD model is carried out. A suitable model is selected for improvement, and the influence of various cabin activities on the virus transmission and diffusion path is considered, such as the aircraft experiencing bumps and the activities of people in the cabin.

[0038] Step S202, import the *.IGS file obtained in step S1 into the ICEM CFD pre-processor, first repair the solid model, define the size of each part, and use the unstructured meshing method to mesh the solid model (that is, the constructed cabin physical model). The total number of grids in the 7-row cabin is about 4.8 million. The three-view drawing of the meshing result is as follows: Figure 5 , 6 , 7, and output *.msh file. GAMBIT and other pre-processors can also be used for meshing.

[0039] Step S3, numerical simulation calculation is performed using FLUENT, which is a CFD calculation software and is widely used in aerospace, automobile design, oil and gas, turbine design, etc. In this embodiment, the divided grid of the physical model obtained in step S2 is imported into the FLUENT software, and the FLUENT software is used to perform numerical simulation of virus propagation in the cabin of a civil aviation passenger aircraft to obtain the numerical simulation results of virus propagation in the cabin of a civil aviation passenger aircraft.

[0040] Step S301, open FLUENT software, input the *.msh file of step S2 into FLUENT and check the mesh, if the mesh volume is negative, re-divide the mesh;

[0041] Step S302, the turbulence model selects the RNG k-ε model;

[0042] Step S303, setting of parameter conditions and boundary conditions. In this embodiment, according to the simulation scene of the civil aviation cabin and the release state of the virus, the parameter conditions and the boundary conditions of the inlet and outlet speeds, temperatures, and the pathogen release rate of the sick passengers are set in the FLUENT software;

[0043] Step S304, setting convergence conditions and defining initial conditions;

[0044] Step S305, after the relevant parameters are set, the number of iterations is set and iterative calculation is performed. When the residual no longer decreases in the residual graph, it is considered that the operation has converged.

[0045] Stop the operation and get the operation result;

[0046] Step S306, save the result.

[0047] Step S4, analysis and evaluation of the numerical simulation results of virus transmission in civil aviation passenger aircraft cabins. The results of numerical simulation are analyzed and studied using the post-processing software provided by FLUENT. The simulation path of virus transmission and diffusion, as well as the velocity field and concentration field of diffusion, are obtained through FLUENT simulation calculations. The diffusion law of virus transmission in the cabin is analyzed to reduce the exposure risk of passengers and crew members.

[0048] Step S5, construction of a mathematical model for virus transmission inside a civil airliner cabin. When the personalized ventilation opening above the seat of an infected passenger is opened and closed, it will have different effects on the air flow inside the civil airliner cabin. The present invention corrects the Wells-Riley model to calculate the infection risk probability of passengers inside the cabin when the personalized ventilation opening above the infected passenger is in different states. The Wells-Riley model is as follows:

[0049]

[0050] Where: P is the infection probability; D is the number of infected people; S is the number of susceptible people; I is the number of diseased people; q is the virus unit release rate (quanta / h); p is the pulmonary ventilation rate; Q is the cabin ventilation volume; r is the ability to cause infection, and t is the exposure time.

[0051] The formula for the corrected Wells-Riley model is as follows:

[0052]

[0053] In the formula, α i is the degree of opening of the personalized ventilation opening above the seat of the infected passenger. In this embodiment, α i = {α1, α2, α3}, α1 represents not opened, α2 represents opened 50%, and α3 represents fully opened; Q0 is the maximum ventilation volume of the personalized ventilation opening above the passenger seat.

[0054] Step S6, analysis of virus transmission inside the cabin under unsteady conditions. Due to the movement of passengers and crew inside the cabin, the transmission route of the virus may change. The present invention constructs a dynamic mesh model of passengers and crew, sets the dynamic mesh size and movement speed, and analyzes the impact of passenger activities and cabin services inside the cabin on virus transmission.

[0055] When virus transmission events such as COVID-19 (Corona Virus Disease 2019) and SARS (Severe Acute Respiratory Syndromes) occur inside the cabin, suggestions are provided for crew and passengers to reasonably arrange cabin activities and use personal protective equipment, reduce the infection risk of other passengers, isolate the infected as much as possible, and block virus transmission.

[0056] This invention studies the virus transmission and diffusion methods inside a civil airliner cabin, establishes a mathematical model using CFD calculation methods, conducts numerical simulations using the FLUENT software, obtains the simulated paths of virus transmission inside the civil airliner cabin, and finally analyzes the simulation results to analyze the laws of virus transmission and diffusion inside the civil airliner cabin, reducing the occupational exposure risks of crew members from the perspective of occupational health. And it provides suggestions for the reasonable arrangement of cabin activities and the use of personal protective equipment for crew members and passengers, reduces the infection risks of other passengers, isolates infected persons as much as possible, blocks virus transmission, which is of great significance to the human health of passengers and crew members inside the cabin.

[0057] The above has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. Method for analyzing virus transmission in the cabin of a civil airliner, characterized in that, Including the following steps: Collect civil aviation passenger aircraft parameters, and use 3D modeling software to construct a physical model of the passenger cabin in the selected space; perform mesh division on the constructed physical model of the passenger cabin; simulate the mesh-divided physical model of the passenger cabin; determine the simulated path of virus spread, as well as the velocity field and concentration field of the spread according to the simulation results; Based on the mathematical model of virus transmission in the civil aviation passenger aircraft cabin, calculate the infection risk probability of passengers in the cabin under different states of the personalized ventilation outlet above the sick passenger; Among them, the formula of the mathematical model of virus transmission in the civil aviation passenger aircraft cabin is as follows: Among them, P is the infection probability; D is the number of infected people; S is the number of susceptible people; I is the number of patients; q is the virus unit release rate; p is the pulmonary ventilation rate; Q is the cabin ventilation volume; α i is the i-th degree of opening of the personalized ventilation outlet above the seat of the sick passenger; Q0 is the maximum ventilation volume of the personalized ventilation outlet above the passenger seat, t is the exposure time; the opening degree α of the personalized ventilation outlet above the seat of the sick passenger i is expressed as: α i ={α1, α2, α3}, where α1 means not opened, α2 means opened at a specific ratio, and α3 means fully opened.

2. The method for analyzing virus transmission in the cabin of a civil airliner according to claim 1, characterized in that, The civil aviation passenger aircraft parameters include the overall dimensions of the cabin exterior, internal seats, human body dimensions, entrance and exit positions, the number of entrances and exits, and the entrance and exit dimensions.

3. The method for analyzing virus transmission in the cabin of a civil airliner according to claim 1, characterized in that, The simulation of the mesh-divided physical model of the passenger cabin specifically includes the following steps: Import the divided mesh into the FLUENT software, perform mesh inspection. If the mesh volume is negative, re-divide the mesh; set the turbulence model and select the RNG k-ε model; set the boundary conditions for the entrance and exit velocity, flow rate, and temperature; select the number of iterations, and obtain the simulation results when the results no longer converge.

4. The method for analyzing virus transmission in the cabin of a civil airliner according to claim 1, characterized in that, The method further includes: analyzing the impact of passenger activities and cabin service movement in the cabin on virus transmission in the cabin under unsteady conditions by setting the moving mesh size and the moving speeds of passengers and crew in the cabin.

5. The method for analyzing virus transmission in the cabin of a civil airliner according to claim 1, characterized in that, Use the unstructured mesh division method to perform mesh division on the physical model of the passenger cabin.

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