Method and system for determining safe evacuation distance of personnel on high-speed maglev railway platform

Abstract

The present invention relates to the technical field of railway safety monitoring, and particularly relates to a method and system for determining the safe avoidance distance of personnel on a high-speed maglev railway platform. The method first constructs a train model and a human body model, and then divides the grid to analyze parameters such as aerodynamic force and flow field structure when a high-speed train with a speed of 600 km / h passes through the platform to obtain the force analysis result. Based on the force analysis result, the safe avoidance distance is determined. In this way, the characteristics of the vehicle-person coupled flow field structure when the train passes through the platform at different speeds are fully studied, and the force characteristics of the human body at different distances are obtained, so that the safe avoidance distance of personnel can be quickly determined.

Description

Technical Field

[0001] The present invention relates to the technical field of railway safety monitoring, and particularly to a method and system for determining the safe evacuation distance of platform personnel on a high-speed maglev railway. Background Art

[0002] The train wind caused by high-speed trains with a speed of 600 km / h has been greatly increased, and a strong negative pressure area appears around the train body, resulting in a sharp deterioration of the aerodynamic characteristics acting on roadside personnel, infrastructure, etc. When the safe evacuation distance of roadside personnel and the relative position between the facilities and the vehicle are unreasonable, it is very likely that waiting passengers on the platform and roadside workers will be blown down by strong airflows, and roadside facilities will vibrate or even be damaged due to aerodynamic excitation, causing serious potential safety hazards to train operation. Currently, there are corresponding standards and specifications for the safe evacuation distance of high-speed wheel-rail railways at home and abroad, but these standards and specifications are only for high-speed railways with a speed of 350 km / h. However, the speed of high-speed trains with a speed of 600 km / h is too high, and its vehicle width is also larger than that of the existing Harmony and Fuxing high-speed wheel-rail trains, and its impact on the safety of roadside personnel is more serious. The existing safe evacuation distance for the human body on high-speed wheel-rail railways can no longer meet the safety requirements of roadside personnel.

[0003] For high-speed wheel-rail railways, different safety standards have been adopted for the safety of roadside personnel in various countries. Some countries use 9 m / s as the safety standard, some countries use an average wind speed of 11 m / s as the platform safety standard, and an average wind speed of 17 m / s as the safety standard for roadside workers. China adopts an average wind speed of 14 m / s as the safety standard and stipulates that the safety distance on the track side is 3 m. There are also some countries that use aerodynamic force as a criterion and stipulate that the aerodynamic force borne by the human body cannot be greater than 100 N. However, currently, there is no systematic analysis of the safe evacuation distance of roadside personnel for the 600 km / h high-speed maglev system internationally, and no corresponding safe evacuation distance has been proposed. Therefore, there is an urgent need to provide a method for determining the safe evacuation distance of platform personnel on a 600 km / h high-speed maglev railway. Summary of the Invention

[0004] The present invention provides a method and system for determining the safe evacuation distance of platform personnel on a high-speed maglev railway to solve the problem in the prior art that it is difficult to accurately calculate the safe evacuation distance of roadside personnel for the 600 km / h high-speed maglev system.

[0005] To achieve the above object, the present invention is realized through the following technical solutions:

[0006] In a first aspect, the present invention provides a method for determining the safe evacuation distance of platform personnel on a high-speed maglev railway, including:

[0007] S1: Construct a train model and a human body model, and determine the computational domain and boundary conditions based on the train model and the human body model;

[0008] S2: Determine the computational grid according to the computational domain and boundary conditions, where the computational grid includes a train grid and a surface grid of the human body model;

[0009] S3: Determine the turbulence model based on the computational domain, boundary conditions, and computational grid;

[0010] S4: Simulate the pressure amplitude on the human body surface when the train passes by the human body based on the train grid, the surface grid of the human body model, and the turbulence model, and determine the pressure distribution contour map based on the pressure amplitude;

[0011] S5: Conduct a flow field structure analysis based on the pressure distribution contour map;

[0012] S6: Conduct a force analysis based on the results of the flow field structure analysis, and determine the safe retreat distance based on the results of the force analysis. In a second aspect, the present application provides a system for determining the safe retreat distance of personnel on a high-speed maglev railway platform, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the method described in the first aspect above are implemented.

[0013] Beneficial effects:

[0014] The method for determining the safe retreat distance of personnel on a high-speed maglev railway platform provided by the present invention first constructs a train model and a human body model, and then divides the grid to analyze parameters such as aerodynamic force and flow field structure when a high-speed train with a speed of 600 km / h passes through the platform to obtain the results of the force analysis, and determines the safe retreat distance based on the results of the force analysis. In this way, the characteristics of the vehicle-person coupled flow field structure when the train passes through the platform at different speeds are fully studied, and the force characteristics of the human body at different distances are obtained, and the safe retreat distance of personnel can be quickly determined. Description of the drawings

[0015] Figure 1 is a flowchart of a method for determining the safe retreat distance of personnel on a high-speed maglev railway platform according to a preferred embodiment of the present invention;

[0016] FIG. 2(a) is a schematic diagram of the train after smoothing treatment, and FIG. 2(b) is a schematic diagram of the train model and the human body model;

[0017] FIG. 3(a) is a schematic diagram of the layout of monitoring points for train-induced wind in the platform space, and FIG. 3(b) is a schematic diagram of the layout of monitoring points for the air pressure distribution on the human body surface;

[0018] Figure 4 is a schematic diagram of the numerical simulation area and computational boundary conditions for a high-speed train passing through a waiting platform;

[0019] Figure 5 Schematic diagram of the computational grid of the preferred embodiment of the present invention, (a) is the grid of the train surface and the surrounding ground; (b) is the grid of the boundary layer of the train surface; (c) is the grid of the human body surface and the surrounding ground; (d) is the grid of the boundary layer of the human body surface;

[0020] Figure 6 This is a schematic diagram of the pressure change on the surface of people1 in a preferred embodiment of the present invention;

[0021] Figure 7 A schematic diagram showing the comparison of pressure changes between the human surface and the vehicle side according to a preferred embodiment of the present invention;

[0022] Figure 8 The preferred embodiment of the present invention is Figure 6 The corresponding pressure amplitude appears at the position where the human body is subjected to force, where (a) is Figure 6 In (a), the human body is under pressure, and (b) Figure 6 In (b), the human body is under pressure, and in (c), Figure 6 In the middle (c), the human body is under pressure, and (d) Figure 6 In the middle (d) position, the human body is under pressure;

[0023] Figure 9 A schematic diagram of wind speed variation on a person's surface according to a preferred embodiment of the present invention;

[0024] Figure 10 A schematic diagram of the force law of people1 in a preferred embodiment of the present invention;

[0025] Figure 11 (a) shows the force condition in the XY plane when the leading car of the high-speed train passes by, and Figure 11 (b) shows the force condition in the XY plane when the trailing car of the high-speed train passes by;

[0026] Figure 12 (a) is a schematic diagram of the force applied to personnel at different positions when a high-speed train passes through a platform at a speed of 600 km / h. Figure 12 (b) is a schematic diagram of the surface wind speed of personnel at different positions when a high-speed train passes through a platform at a speed of 600 km / h. Figure 12 (c) is a schematic diagram of the wind speed at the wind measurement point when a high-speed train passes through a platform at a speed of 600 km / h.

[0027] Figure 13 (a) shows the forces on people at different positions when a high-speed train passes through the platform at different speeds; Figure 13 (b) shows the wind speed on the surface of people at different positions when a high-speed train passes through the platform at different speeds; Figure 13 (c) shows the wind speed at wind measurement points at different positions when there are no people when a high-speed train passes through the platform at different speeds;

[0028] Figure 14(a) shows the relationship between the slipstream velocity and the distance from the center line of the track at different vehicle speeds. Figure 14(b) shows the relationship between the wind speed on the human body surface and the distance from the center line of the track at different vehicle speeds. Figure 14(c) shows the relationship between the aerodynamic force on the human body and the distance from the center line of the track at different vehicle speeds. Detailed implementation manner

[0029] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, the terms such as "a" or "one" do not denote a quantity limitation, but mean that there is at least one.

[0031] It should be understood that it is currently difficult to determine the safe evacuation distance for the 600-km / h high-speed maglev system. Based on this, the present application provides a method for determining the safe evacuation distance of personnel on the high-speed maglev railway platform. In other words, the train in the present application can be a maglev train.

[0032] Please refer to Figure 1 , a method for determining the safe evacuation distance of personnel on the high-speed maglev railway platform provided by the present application includes:

[0033] S1: Construct a train model and a human body model, and determine the computational domain and boundary conditions according to the train model and the human body model.

[0034] In this step, the train is a three-car formation, and the boundary conditions include overlapping grid boundary conditions, wall boundary conditions, and free flow boundary conditions.

[0035] S2: Determine the computational grid according to the computational domain and boundary conditions, and the computational grid includes the train grid and the surface grid of the human body model.

[0036] S3: Determine the turbulence model according to the computational domain, boundary conditions, and computational grid.

[0037] In this step, the IDDES model in the simulation software is adopted, and a transition function and a limiting function are introduced to delay the transition between RANS and large eddy simulation LES, reduce the dependence of DES on the grid, and effectively avoid the phenomena of "grid-induced separation" and "near-avoidance of stress depletion". The IDDES method combines with the SST K-ω model to simulate the flow field structure when the train passes through the platform. Since the train speed reaches 600 km / h, a compressible model is selected, and the second order is used for both spatial discretization and temporal discretization to achieve higher solution accuracy. The time step is set to 1.2×10 -4 .

[0038] S4: Based on the train grid, the surface grid of the human body model, and the turbulence model, simulate the pressure amplitude on the surface of the human body when the train passes by the human body, and determine the pressure distribution contour map based on the pressure amplitude.

[0039] S5: Conduct a flow field structure analysis based on the pressure distribution contour map.

[0040] S6: Conduct a force analysis based on the results of the flow field structure analysis, and determine the safe evacuation distance based on the results of the force analysis.

[0041] The above method for determining the safe evacuation distance of personnel at a high-speed maglev railway platform first constructs a train model and a human body model, and then divides the grid to analyze parameters such as aerodynamic force and flow field structure when a high-speed train with a speed of 600 km / h passes through the platform to obtain the results of the force analysis, and determines the safe evacuation distance based on the results of the force analysis. In this way, the characteristics of the vehicle-person coupled flow field structure when the train passes through the platform at different speeds are fully studied, the characteristics of the human body force at different distances are obtained, and the safe evacuation distance of personnel can be quickly determined.

[0042] Optionally, the constructing of the train model and the human body model includes:

[0043] Perform a smoothing treatment on the surface of the train, and obtain the size information of the train;

[0044] Arrange N human body models on the platform side close to the train, and arrange M measuring points along the height direction at the middle position of the front of each human body model, with a distance of Q cm between every two adjacent measuring points;

[0045] Correspondingly arrange P measuring points at the same height and lateral position as the measuring points of the human body model but in the place where there is no one beside the train, where P = M;

[0046] Construct the train model and the human body model based on the size information of the train, the N human body models, the M measuring points, and the P measuring points.

[0047] In this optional implementation manner, N is taken as 5, M is taken as 9, and Q is taken as 20. Here, it is only for example and not limited.

[0048] Determining the computational domain and boundary conditions according to the train model and the human body model includes:

[0049] Determining the computational domain based on the size information and setting requirements of the train;

[0050] Using the overlapping grid method to simulate the relative movement between the human and the train, and setting an overlapping area around the train, where the overlapping area moves forward at the vehicle speed;

[0051] Setting the outer surface of the overlapping area as the overlapping grid boundary condition, setting the surface of the train body, the surface of the human body model, the ground and the track corresponding to the computational domain as the wall boundary condition, and setting the side and top surfaces of the computational domain as the free stream boundary condition;

[0052] The setting requirements include:

[0053] Meeting the full development of the flow field.

[0054] In one example, Fig. 2(a) is a schematic diagram after the train has been smoothed, and Fig. 2(b) is a schematic diagram of the train model and the human body model. The train is composed of three cars. For the convenience of numerical calculation, the details on the train surface are smoothed without affecting the calculation results. The height of the train is 4.20 m, and the vehicle height is denoted as H as the characteristic dimension. The vehicle width is 0.88H, and the total vehicle length is 19.34H. For the convenience of calculation, a simplified human body model is adopted. Fig. 3(a) is a schematic diagram of the measuring points, and Fig. 3(b) is a schematic diagram of the measuring points of the human body model. Details such as facial features and limbs are ignored, and only the general shape is retained. The height of the human body model is 1.7 m, which is 0.405H. The train runs on a double-track railway with a track center-to-center distance of 5.1 m, and the train runs on the right side of the platform. The human body model is arranged on the platform side close to the train. The first person is denoted as P1, 3 m away from the center line of the right track. The next person is denoted as P2, 0.5 m farther from the right track and 10 m farther along the running direction of the train to ensure that adjacent human body models do not affect each other. P3, P4, and P5 are arranged in the same way, and a total of 5 human body models are arranged. To monitor the surface pressure and speed of the human body, measuring points are arranged at intervals of 20 cm along the height direction at the middle position of the front of the human body, and a total of 9 measuring points are arranged. The surface measuring points of the first person are denoted as P1-1 to P1-9 from bottom to top, and the surface measuring points of the second person are denoted as P2-1 to P2-9 from bottom to top. Measuring points are correspondingly arranged at the same height and lateral position as the surface measuring points of the human body but in a place where there is no one beside the train to facilitate the comparison of the differences in the train wind when there is someone and when there is no one. A row corresponding to the surface measuring points of P1 is denoted as C1, and the measuring points are denoted as C1-1 to C1-9 from bottom to top. It is worth explaining that since the numerical simulation method is adopted in this application, the area for simulating the train running space in the numerical simulation cannot be infinitely large. Therefore, a finite square area is used to represent the infinite space. In the case of representing the infinite space, reasonable definitions, that is, boundary conditions, need to be given to the six faces of the square calculation domain to ensure the accuracy of the simulation. As Figure 4 shown, where 4-1 is the free-stream boundary; 4-2 is the track; 4-3 is the ground; 4-4 is the human body; 4-5 is the overlapping area; 4-6 is the high-speed train. In the numerical simulation calculation, the human body 4-4, the high-speed train 4-6, the ground 4-3, etc. are regarded as solid wall boundaries, the track 4-2 is set, the overlapping area 4-5 is determined, and the side surfaces of the calculation area are set as the free-stream boundary 4-1 to better simulate the flow of the flow field on both sides.

[0055] Specifically, the size of the computational domain is: 142.9H × 28.6H × 16.7H, which can ensure the full development of the flow field. When performing numerical calculations, the overlapping grid method is used to simulate the relative movement between the train and the human body. An overlapping area is set around the train, with a size of 36.9H × 1.3H × 1.4H, and the overlapping area moves forward at the vehicle speed. The outer surface of the overlapping area is set as the overlapping grid boundary condition, the surface of the vehicle body, the surface of the human body, the ground of the computational domain, and the track are set as the wall boundary conditions, and the side and top surfaces of the computational domain are set as the free flow boundary conditions with a flow velocity of 0.

[0056] Optionally, S2 includes:

[0057] Arrange several layers of boundary layer grids on the train surface according to the computational domain and boundary conditions, and set the growth rate and total thickness of the boundary layer grids; and set the minimum size of the train grids, the minimum size of the grids on the surface of the human body model, the minimum size of the grids in the overlapping area between the train and the human body, the total number of grids, and the number of grids in the overlapping area.

[0058] In an example, as Figure 5 shown, the cutting body grids are used as the computational grids in this application: among them, (a) are the grids on the train surface and the surrounding ground; (b) are the boundary layer grids on the train surface; (c) are the grids on the human body surface and the surrounding ground; (d) are the boundary layer grids on the human body surface. 10 layers of boundary layer grids are arranged on the train surface, the growth rate of the boundary layer grids is 1.2, and the total thickness is 0.005 mm. The Y+ range on the train surface is as Figure 5 shown, meeting the requirements of the selected numerical calculation method in this application. To calculate and capture the flow field details at the train tail and around the human body more accurately, the corresponding areas are encrypted. The minimum size of the grids on the train surface is 0.0119H (0.005 / 0.42), the minimum size of the grids on the human body surface is 0.00595H, and the size of the overlapping area is 0.0476H (0.02 mm). The total number of grids is 45.75 million, and the number of grids in the overlapping area is 17.25 million.

[0059] Optionally, S4 includes:

[0060] Obtain the positive pressure amplitude and negative pressure amplitude of the flow field acting on the human body model when the leading car passes by, denoted as the first positive pressure amplitude and the first negative pressure amplitude; determine point a of the pressure distribution diagram according to the first positive pressure amplitude, and determine point b of the pressure distribution diagram according to the first negative pressure amplitude;

[0061] Obtain the negative pressure amplitude and positive pressure amplitude of the flow field acting on the human body model when the trailing car passes by, denoted as the second negative pressure amplitude and the second positive pressure amplitude; determine point c of the pressure distribution diagram according to the second negative pressure amplitude, and determine point d of the pressure distribution diagram according to the second positive pressure amplitude;

[0062] Determine the final pressure distribution contour map according to the pressure values at the cross-sections of points a, b, c, and d.

[0063] The said S5 includes:

[0064] Analyze the final pressure distribution nephogram, and it is obtained that the positive pressure amplitude at point a is greater than that at point d, and the negative pressure amplitude at point b is greater than that at point c; according to the pressure values at the cross-sections of points a, c, and d, it is obtained that the pressure on the lower half of the human body is greater than that on the upper half, and according to the pressure value at the cross-section of point b, it is obtained that the pressure in the middle of the human body is the greatest.

[0065] In this embodiment, the flow field structure analysis is carried out as follows:

[0066] To study the change of the aerodynamic characteristics of people when the train passes by, people1 closest to the train is analyzed. This person is 3 m away from the center line of the right track and 1.212 m away from the platform edge. Figure 6 For the pressure change on the surface of people1 when the train passes by the platform and the pressure nephogram of the train when there is no one, the pressure change on the surface of the person is corresponding to its relative position on the train for analysis. Among them, Figure 6 in refers to the negative pressure area of the platform caused by the leading car of the train passing through the platform head, and the minimum pressure extreme value appears here, Figure 7 is the comparison of the pressure changes between the surface measurement points P1-5 of the person and the corresponding measurement points C1-5 at the place without people. It can be found that when there is someone and when there is no one, the pressure changes are basically the same. Only when the person passes by, the positive and negative pressure amplitudes of the surface measurement points P1-5 of the person are greater than those of the measurement points without people. Therefore, it is reasonable to analyze the pressure characteristics on the surface of the person when there is someone with the nephogram around the train when there is no one. Figure 8 In the preferred embodiment of the present invention, the human body is stressed at the position where the pressure amplitude corresponding to Figure 6 appears. Among them, (a) is the human body being pressed at the position (a) in Figure 6 , (b) is the human body being pressed at the position (b) in Figure 6 , (c) is the human body being pressed at the position (c) in Figure 6 , and (d) is the human body being pressed at the position (d) in Figure 6 .

[0067] It should be noted that when the leading car passes by, a positive pressure amplitude appears first and then a negative pressure amplitude, which are respectively Figure 6 the points (a) and (b) in Figure 6 . Combining the pressure distribution around the train when there is no one, the positive pressure amplitude and the negative pressure amplitude should appear respectively when the front of the train is about to pass by the person and when the streamlined head of the train has not completely passed by the person. The corresponding positions are as shown in the nephogram in Figure 6Points (c) and (d) appear respectively when the streamlined part of the rear car passes by and after the rear of the car passes by, as Figure 6 shown in the contour map.

[0068] Take Figure 6 the pressure distribution contour maps at four cross-sections (a), (b), (c), and (d) in it for further analysis. The positive pressure value at (a) is greater than the positive pressure value at (d), and the range of pressure radiation in the transverse direction is also wider. The negative pressure value at (b) is greater than the negative pressure value at (c). That is, the positive and negative pressure amplitudes when the head car passes by are both greater than the pressure amplitudes when the rear car passes by. This conclusion can also be obtained from Figure 7. In addition, the distribution characteristics of pressure in the height direction can be seen. Figure 6 At the three cross-sections (a), (c), and (d) in it, the pressure on the lower half of the human body is greater than that on the upper half. Figure 6 In it, P1-5 and P1-1 have close pressures and are greater than P1-9. At (b), the pressure in the middle of the human body is the greatest because due to the limitation of the platform on the space, a vortex structure is generated on the platform side and develops to the middle and lower parts of the human body at (b). Therefore, the pressure at measurement point P1-5 is greater than the pressure at measurement point P1-1 which is greater than the pressure at measurement point P1-9.

[0069] Optionally, the S6 includes:

[0070] Perform a force analysis with the forward direction of the train as the positive X direction, the side of the train platform as the negative Y direction, and the top of the train as the positive Z direction;

[0071] Analyze the force conditions of the human body model in the X direction and the Y direction when the head car passes by and when the rear car passes by respectively to obtain the force analysis results. The force analysis results include the force on the human body model in the X-Y plane, the surface wind speed of the human body model, and the variation of the wind speed amplitude at the measurement points where there is no one with the change of the distance between the person and the train;

[0072] Calculate the safe retreat distance based on the force analysis results and the safety threshold.

[0073] In this embodiment, the force analysis based on the flow field analysis results is as follows:

[0074] As Figure 9 shown, from the analysis of the flow field structure, the severe stages of the change in the human flow field structure mainly concentrate when the head and the rear of the car pass by. Correspondingly, finally analyze the force conditions of the human body when the head car and the rear car pass by. Figure 9 in refers to the negative pressure area of the platform caused by the head car of the train passing through the platform, and the minimum pressure extreme value appears here.

[0075] For the convenience of analysis, the forward direction of the train is defined as the positive X direction, the left side of the train is the positive Y direction (i.e., the platform side is the negative direction), and the top of the train is the positive Z direction. Among them, Fig. 11(a) shows the force condition in the X-Y plane when the leading car of the high-speed train passes by, and Fig. 11(b) shows the force condition in the X-Y plane when the trailing car of the high-speed train passes by. Figure 10 It is the change in the force exerted on a person when the train passes by. When the leading car passes by, a large force is exerted. When the intermediate car passes by, the force gradually decreases. When the trailing car passes by, a large force is exerted again, which is comparable to that when the leading car passes by, and then it decreases.

[0076] Further analyze the variation law of the direction of the force exerted on a person. Figure 10 It is the variation law of the component force exerted on people1 when the train passes by, and the positions where the pressure amplitudes (a)-(d) and the velocity amplitudes (e)-(h) appear are marked in the figure. The force amplitude points can be corresponding to the positions in the cloud diagram for convenient analysis.

[0077] It can be seen that the forces exerted on a person are mainly in the X and Y directions, and the force in the Z direction is relatively small, with a maximum of about 30 N. Moreover, the position where the maximum value in the Z direction appears is not at the position where the total force on the person is the largest, and it has a very small impact on the maximum value of the resultant force on the person. Therefore, in the subsequent analysis, the X and Y directions are mainly considered. For the X direction, when the leading car passes by, a relatively small positive force is first generated, not exceeding 50 N, pushing the person forward. Then it quickly becomes a large negative force, exceeding 100 N. Map the cross-sections (a)-(h) analyzed above to the corresponding positions. The cross-section where the forward force appears is around cross-section (a), that is, when the front of the train is about to reach the position of the person. At this time, the front of the train displaces the air in front, generating a positive pressure area, and the force acting on the person is forward. The position where the maximum value of the X negative direction force appears is near cross-section (e), which corresponds to the position where the positive pressure area transitions to the negative pressure area. There is positive pressure in front of the person and negative pressure behind, so a large backward acting force is generated on the person. Then the acting force decreases to a very small value, and the force becomes 0 near cross-section (f), and a relatively small negative force gradually appears. At this time, the person is still in the negative pressure area, and the force generated is backward. A negative force appears in the Y direction after cross-section (a), pushing the person away from the train. Combining Figure 6It can be seen that this position is approximately at the junction of the positive pressure area and the zero pressure area. In front of the person is positive pressure, and behind the person is negative pressure, and a lateral force away from the vehicle towards the rear is exerted. Subsequently, the Y-direction force rapidly decreases and becomes a positive force, and it fluctuates twice within the range of 0 - 70 N. The range where the positive force appears is approximately between section (e) and section (g), which exactly corresponds to the stage when the vortex generated and developed on the platform affects the person. At this time, in front of the person is the vortex area, which is negative pressure, and the negative pressure behind the person is small, generating a forward force that sucks the person towards the vehicle. Taking the time period when the force amplitude occurs as the head car passes by, 0.81 s - 0.9 s, the change in the direction of the force exerted on the person in the X - Y plane is plotted as shown in Figure 12(a). The entire process mainly shows an outward and backward force that pushes the person outwards, and the force changes in a clockwise direction during the force - receiving process, first increasing, then decreasing, then increasing again, and then decreasing again.

[0078] When the rear car passes by, the change in the X - direction force is similar to but comparable to that when the head car passes by. First, there is a very small reverse force, and then there is a very large positive force, corresponding to the section at the maximum value of the wind speed (h), approximately at the transition from negative pressure to positive pressure, with negative pressure in front and positive pressure behind, and a forward force is exerted. Then there is a very small reverse force. After section (d), corresponding to after the rear car passes by, the positive pressure in front is greater than the positive pressure behind, and the force is towards the rear. When the rear car passes by, the force exerted in the Y - direction is similar to but opposite to that of the head car. First, a very large positive force is generated, approximately near section (c). At this time, in front of the person is a very large negative pressure area, and behind the person is a relatively small negative pressure, generating a forward force that sucks the person towards the vehicle. Subsequently, the positive force rapidly decreases and becomes a relatively small reverse force, corresponding to the positive pressure area of section (d). Taking the time period of the force amplitude when the rear car passes by, 0.125 - 0.135, the change in the magnitude and direction of the force in the X - Y plane is plotted as shown in Figure 12(b). The entire process shows a forward and inward force that sucks the person inwards, and the force changes in a clockwise direction during the process, first increasing and then decreasing.

[0079] According to relevant standards, a force of 100 N can be used as the safety threshold for the force exerted on a person. During the process of the head and rear cars passing by, the person is in a dangerous state as the force exerted on the person exceeds 100 N for a certain period of time. Therefore, it is necessary to increase the distance between the vehicle and the person to ensure the safety of the personnel.

[0080] Specifically, Fig. 12(a) shows the force conditions of people at different positions when a high-speed train passes through the platform at a speed of 600 km / h; Fig. 12(b) shows the surface wind speeds of people at different positions when a high-speed train passes through the platform at a speed of 600 km / h; Fig. 12(c) shows the wind speeds at the wind measurement points under the condition of people at different positions when a high-speed train passes through the platform at a speed of 600 km / h. First, three height measurement points are set on the human model, namely height 1, height 5, and height 9. It can be seen from Fig. 12(a), Fig. 12(b), and Fig. 12(c) that as the distance increases, both the force on people and the wind speed show an obvious decreasing trend, and the decreasing effect is the most obvious in the place closer to the train. Taking the force on people as an example, when the distance increases from 3 m to 3.5 m, the force on people decreases by 40.5 N, with a relative decrease of 29.2%. When the distance increases from 4.5 m to 5 m, the force on people decreases by 12 N, with a relative decrease of 20.9%. The wind speeds at the surface measurement points of people and the wind speeds at the measurement points without people both decrease, but their laws are different. For the measurement points without people, at a distance of 3 m, the wind speed at height 5 is greater than that at height 1 and height 9, and the speed in the middle is the largest. After the distance increases to 3.5 m, the wind speeds at the three height measurement points are basically close, and the wind speed at height 9 is slightly smaller, indicating that the farther away from the train, the smaller the wind speed difference in the height direction. For the surface measurement points of people, it is larger at 3 m. After 3.5 m and later, the wind speed at height 1 is greater than that at height 5 and height 9. It may be because of the influence of people. At height 5 and height 9, the flow is blocked and the wind speed is smaller. Among them, Fig. 13(a) shows the force conditions of people at different positions when a high-speed train passes through the platform at different speeds; Fig. 13(b) shows the surface wind speeds of people at different positions when a high-speed train passes through the platform at different speeds; Fig. 13(c) shows the wind speeds at the wind measurement points under the condition of no people at different positions when a high-speed train passes through the platform at different speeds. It can be seen that the variation laws of the three aerodynamic data are similar, decreasing with the decrease of the vehicle speed, approximately showing a linear law. The decrease of people1 closest to the vehicle is the most obvious, and the decrease of people2 and people3 farther away from the vehicle is smaller and closer.

[0081] Furthermore, based on the obtained data, the safe evacuation distance for personnel is determined. There are many train wind safety standards. In this application, the safety thresholds are set as a force of 100 N, wind speeds of 14 m / s and 17 m / s to determine the safe evacuation distance for personnel. Among them, Figure 14(a) shows the relationship between the downwash flow velocity and the distance from the center line of the track at different vehicle speeds, Figure 14(b) shows the relationship between the wind speed on the human body surface and the distance from the center line of the track at different vehicle speeds, and Figure 14(c) shows the relationship between the aerodynamic force on the human body and the distance from the center line of the track at different vehicle speeds. If judged by the maximum value of the wind speed on the human surface, when the train is running at 600 km / h, the safe distances obtained with 17 m / s and 14 m / s are 4.04 m and 4.62 m respectively. Currently, the recommended high-speed rail safety distance in China is 3 m from the center of the track. The distances obtained based on this data far exceed 3 m, and are 2.19 m and 2.77 m from the edge of the platform. Considering the space limitation of the platform, this distance is obviously too large. If the maximum value of the speed at the side of the vehicle is selected, the safe distances obtained with 17 m / s and 14 m / s as the speed limits are 3.64 m and 3.97 m respectively. If the force on the human body is considered and the safety standard of 100 N is used for calculation, the obtained safe distance is the smallest, which is 3.51 m. The evacuation distances obtained by different standards are all greater than the current safe evacuation distance, and the results obtained using the speed at the side of the train and the force on the human body are closer. According to the previous analysis, people have a greater impact on the flow field around the train, making the speed on the human surface greater than the speed at the corresponding position without people. The safe distance obtained based on this data is relatively larger.

[0082] If the train operating speed is reduced to 550 km / h and 500 km / h, the safe distances obtained with the speed at the side of the vehicle of 17 m / s and 14 m / s are 3.80 m and 3.61 m respectively. Compared with 600 km / h, the vehicle speed is reduced by 8.33% and 16.67%, and the safe distances are reduced by 4.28% and 9.07% respectively. Reducing the vehicle speed can significantly reduce the safe distance, but when the vehicle speed is reduced to 500 km / h, the safe distance standard still cannot be met. Therefore, if you want to reduce the safe distance to a relatively low range, the vehicle speed needs to be reduced to a sufficiently low level. The advantage of the train lies in its high operating speed. If the speed is reduced too much when passing through the platform, it will affect its operation. Therefore, comprehensive consideration is needed.

[0083] In summary, based on the method for determining the safe retreat distance for platform personnel on a high-speed maglev railway provided in this application, it can be determined that the platform will destroy the symmetry of the flow field structure of the train, generate a vortex structure at the front of the train on the platform side and gradually develop and move upward, causing the human body to bear greater pressure and wind speed, affecting the aerodynamic characteristics of the person; when the front and rear trains of the train pass by, the aerodynamic force borne by the human body is the largest and very close, and the surface pressure of the human body when the front train passes by is greater than the surface pressure when the rear train passes by; in the height direction, the pressure load and wind speed borne by the middle part of the human body are the largest; increasing the distance between people and vehicles can reduce the load on the human body. As the distance between people and vehicles increases, the effect of reducing the load by increasing the same distance gradually decreases; reducing the speed of the train can reduce the load on the human body, and the reduction effect is approximately linear; when the train runs at 600km / h, with a wind speed of 14m / s beside the train as the safety standard, the safe retreat distance of platform personnel is 3.97m, and when the speed drops to 550km / h and 500km / h, the distances are 3.80m and 3.61m, respectively.

[0084] The embodiment of the present application also provides a system for determining the safe retreat distance of personnel on a high-speed maglev railway platform, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the above method when executing the computer program. The system for determining the safe retreat distance of personnel on a high-speed maglev railway platform can implement various embodiments of the above method and achieve the same beneficial effects, which will not be described in detail here.

[0085] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for determining the safe evacuation distance of personnel on a high-speed maglev railway platform, characterized in that, Including: S1: Construct a train model and a human body model, and determine the computational domain and boundary conditions according to the train model and the human body model; S2: Determine the computational grid according to the computational domain and the boundary conditions, and the computational grid includes a train grid and a surface grid of the human body model; S3: Determine the turbulence model according to the computational domain, the boundary conditions and the computational grid; S4: Simulate the pressure amplitude on the human body surface when the train passes by the human body based on the train grid, the surface grid of the human body model and the turbulence model, and determine the pressure distribution contour map based on the pressure amplitude; S5: Conduct a flow field structure analysis based on the pressure distribution contour map; S6: Conduct a force analysis based on the results of the flow field structure analysis, and determine the safe avoidance distance based on the results of the force analysis; The construction of the train model and the human body model includes: Smoothing the surface of the train and obtaining the size information of the train; Arrange N human body models on the platform side close to the train, and arrange M measuring points along the height direction at the middle position of the front of each human body model, with a spacing of Q cm between every two adjacent measuring points; Correspondingly arrange P measuring points at the same height and lateral position as the measuring points of the human body model but where there is no one beside the train, and P = M; Construct a train model and a human body model based on the size information of the train, the N human body models, the M measuring points and the P measuring points.

2. The method for determining the safe evacuation distance of personnel on the high-speed maglev railway platform according to claim 1, characterized in that, The determination of the computational domain and boundary conditions according to the train model and the human body model includes: Determine the computational domain based on the size information of the train and the set requirements; Adopt the overlapping grid method to simulate the relative movement between the train and the human body, and set an overlapping area around the train, and the overlapping area moves forward at the vehicle speed; Set the outer surface of the overlapping area as the overlapping grid boundary condition, set the surface of the train body, the surface of the human body model, the corresponding ground and track of the computational domain as the wall boundary condition, and set the side and top surfaces of the computational domain as the free flow boundary condition; The set requirements include: Meet the development of the flow field.

3. The method for determining the safe evacuation distance of personnel on the high-speed maglev railway platform according to claim 1, wherein The S2 includes: Arrange several layers of boundary layer grids on the train surface according to the computational domain and boundary conditions, set the growth rate and total thickness of the boundary layer grids; and set the minimum size of the train grid, the minimum size of the surface grid of the human body model, the minimum size of the grid in the overlapping area between the train and the human body, the total amount of grids, and the amount of grids in the overlapping area.

4. The method for determining the safe evacuation distance of personnel on the high-speed maglev railway platform according to claim 1, characterized in that, The S4 includes: Obtain the positive pressure amplitude and negative pressure amplitude of the flow field acting on the human body model when the leading car passes by, and record them as the first positive pressure amplitude and the first negative pressure amplitude; determine point a of the pressure distribution map according to the first positive pressure amplitude, and determine point b of the pressure distribution map according to the first negative pressure amplitude; Obtain the negative pressure amplitude and positive pressure amplitude of the flow field acting on the human body model when the trailing car passes by, and record them as the second negative pressure amplitude and the second positive pressure amplitude; determine point c of the pressure distribution map according to the second negative pressure amplitude, and determine point d of the pressure distribution map according to the second positive pressure amplitude; Determine the final pressure distribution contour map according to the pressure values at the four cross-sections of point a, point b, point c and point d.

5. The method for determining the safe evacuation distance of personnel on the high-speed maglev railway platform according to claim 4, characterized in that, The S5 includes: Analyze the final pressure distribution contour map, and it is obtained that the positive pressure amplitude at point a is greater than that at point d, and the negative pressure amplitude at point b is greater than that at point c; according to the pressure values at the cross-sections of points a, c, and d, it is obtained that the pressure on the lower half of the human body is greater than that on the upper half, and according to the pressure value at the cross-section of point b, it is obtained that the pressure in the middle of the human body is the greatest.

6. The method for determining the safe evacuation distance of personnel on the high-speed maglev railway platform according to claim 1, characterized in that The S6 includes: Perform a force analysis with the forward direction of the train as the positive X direction, the side of the train platform as the negative Y direction, and the top of the train as the positive Z direction; Analyze the forces on the human body model in the X direction and the Y direction when the leading car passes and the trailing car passes respectively, and obtain the force analysis results, where the force analysis results include the forces on the human body model in the X-Y plane, the wind speed on the surface of the human body model, and the variation of the wind speed amplitude at the measuring points in the unoccupied area with the distance between the cars; Calculate the safe retreat distance based on the force analysis results and the safety threshold.

7. A system for determining the safe evacuation distance of personnel on a high-speed maglev railway platform, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of any one of the methods described in claims 1 to 6 above.

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