Method and system for determining personnel safety retreat distance of high-speed maglev railway platform

Abstract

The invention relates to the technical field of railway safety monitoring, in particular to a method and a system for determining the personnel safety retreat distance of a high-speed maglev railway platform. Dividing grids to analyze parameters such as aerodynamic force and a flow field structure when the high-speed train with the speed of 600 kilometers per hour passes through the platform to obtain a stress analysis result, and determining the safe retreat distance based on the stress analysis result. Therefore, the structural characteristics of the man-vehicle coupling flow field when the train passes through the platform at different speeds are fully researched, the stress characteristics of human bodies at different distances are obtained, and the safe withdrawing distance of the personnel can be quickly determined.

Description

Technical Field

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

[0002] The train wind caused by high-speed trains with a speed of 600 kilometers per hour has increased significantly, and a strong negative pressure area has appeared around the train body, resulting in a sharp deterioration of the aerodynamic characteristics acting on roadside personnel and infrastructure. If the safety retreat distance of roadside personnel, the setting of facilities and the relative position of vehicles are unreasonable, it is very likely that platform waiting personnel and roadside staff will be blown down by strong airflow, and roadside facilities will vibrate or even be damaged due to aerodynamic excitation, causing serious safety hazards in train operation. At present, there are corresponding standards and specifications for the safety retreat 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 kilometers per hour. The speed of a high-speed train with a speed of 600 kilometers per hour is too high, and its width is also larger than the existing Harmony and Fuxing high-speed wheel-rail trains, which has a more serious impact on the safety of roadside personnel. The existing safety retreat distance of human body in high-speed wheel-rail railways can no longer meet the safety needs of roadside personnel.

[0003] For high-speed wheel-rail railways, different countries have adopted different safety standards for the safety of roadside personnel. Some countries use 9m / s as the safety standard, some countries use an average wind speed of 11m / s as the platform safety standard, and an average wind speed of 17m / s as the safety standard for railway workers. my country uses an average wind speed of 14m / s as the safety standard and stipulates that the trackside safety distance is 3m. Some countries use aerodynamics as a criterion and stipulate that the aerodynamic force that the human body bears cannot be greater than 100N. However, at present, there is no systematic division of the safe retreat distance for roadside personnel in a 600 km / h high-speed maglev system in the world, and no corresponding safe retreat distance has been proposed. Therefore, it is urgent to provide a method for determining the safe retreat distance for 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 retreat distance of platform personnel on a high-speed maglev railway, so as to solve the problem in the prior art that it is difficult to accurately calculate the safe retreat distance of roadside personnel on a high-speed maglev system with a speed of 600 kilometers per hour.

[0005] In order to achieve the above object, the present invention is implemented by the following technical solutions: In a first aspect, the present invention provides a method for determining a safe retreat distance for personnel on a high-speed maglev railway platform, comprising: S1: constructing a train model and a human body model, and determining a calculation domain and boundary conditions according to the train model and the human body model; S2: determining a computational grid according to the computational domain and boundary conditions, wherein the computational grid includes a train grid and a human body model surface grid; S3: Determine the turbulence model based on the computational domain, boundary conditions and computational grid; S4: simulating the pressure amplitude on the surface of the human body when the train passes through the human body based on the train grid, the surface grid of the human body model, and the turbulence model, and determining a pressure distribution cloud map based on the pressure amplitude; S5: Performing flow field structure analysis based on the pressure distribution cloud map; S6: Perform force analysis based on the flow field structure analysis results, and determine the safe retreat distance based on the force analysis results. In a second aspect, the present application provides a system for determining the safe retreat distance for personnel on a high-speed maglev railway platform, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect when executing the computer program.

[0006] Beneficial effects: The method for determining the safe retreat distance of personnel on the high-speed maglev railway platform provided by the present invention first constructs a train model and a human body model, then divides the grid to analyze the aerodynamic force, flow field structure and other parameters when a high-speed train with a speed of 600 kilometers per hour passes through the platform to obtain the force analysis results, and determines the safe retreat distance based on the force analysis results. In this way, the characteristics of the coupled flow field structure of people and vehicles 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 retreat distance of personnel can be quickly determined. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A flowchart of a method for determining a safe retreat distance for personnel on a high-speed maglev railway platform according to a preferred embodiment of the present invention; FIG2( a ) is a schematic diagram of a train after smoothing, and FIG2( b ) is a schematic diagram of a train model and a human body model; Figure 3 (a) is a schematic diagram of the layout of the train wind monitoring points in the platform space, and Figure 3 (b) is a schematic diagram of the layout of the air pressure distribution monitoring points on the human body surface; Figure 4 This is a schematic diagram of the numerical simulation area and calculation boundary conditions for high-speed trains passing through the waiting platform; 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; Figure 6 This is a schematic diagram of the pressure change on the surface of people1 in a preferred embodiment of the present invention; Figure 7A schematic diagram comparing pressure changes on a person's surface and next to a vehicle in a preferred embodiment of the present invention; 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; Fig. 9 A schematic diagram of wind speed variation on a person's surface according to a preferred embodiment of the present invention; Fig.10 This is a schematic diagram of the force law of people1 in a preferred embodiment of the present invention; 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; 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. 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; Figure 14 (a) shows the relationship between the glide velocity and the distance from the track centerline at different vehicle speeds, Figure 14 (b) shows the relationship between the wind speed on the human body surface and the distance from the track centerline at different vehicle speeds, and Figure 14 (c) shows the relationship between the aerodynamic force of the human body and the distance from the track centerline at different vehicle speeds. DETAILED DESCRIPTION

[0008] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0009] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the common meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, the words "one" or "an" and similar words do not indicate a quantity limitation, but indicate the existence of at least one.

[0010] It should be understood that it is currently difficult to determine the safe retreat distance for a high-speed maglev system with a speed of 600 kilometers per hour. Based on this, the present application provides a method for determining the safe retreat distance for personnel on a high-speed maglev railway platform. In other words, the train in the present application may be a maglev train.

[0011] See also Figure 1 The present application provides a method for determining a safe retreat distance for personnel on a high-speed maglev railway platform, comprising: S1: constructing a train model and a human body model, and determining a calculation domain and boundary conditions according to the train model and the human body model.

[0012] In this step, the train is composed of three cars, and the boundary conditions include overlapping grid boundary conditions, wall boundary conditions, and free flow boundary conditions.

[0013] S2: Determine a computational grid according to the computational domain and boundary conditions, wherein the computational grid includes a train grid and a human body model surface grid.

[0014] S3: Determine the turbulence model based on the computational domain, boundary conditions, and computational mesh.

[0015] In this step, the IDDES model in the simulation software is used to introduce transition functions and limit functions to delay the conversion between RANS and LES, reduce the dependence of DES on the grid, and effectively avoid the phenomena of "grid-induced separation" and "near avoidance of stress exhaustion". The IDDES method is combined with the SST K-ω model to simulate the flow field structure when the train passes the platform. Since the train speed reaches 600 km / h, a compressible model is selected, and the spatial discretization and time discretization are second-order to achieve higher solution accuracy. The time step is set to 1.2×10 -4 .

[0016] S4: simulating the pressure amplitude on the surface of the human body when the train passes through the human body based on the train grid, the surface grid of the human body model, and the turbulence model, and determining a pressure distribution cloud map based on the pressure amplitude.

[0017] S5: Perform flow field structure analysis based on the pressure distribution cloud map.

[0018] S6: Performing a force analysis based on the flow field structure analysis result, and determining a safe retreat distance based on the force analysis result.

[0019] The above method for determining the safe retreat distance for personnel on the high-speed maglev railway platform first constructs a train model and a human body model, then divides the grid to analyze the aerodynamic force, flow field structure and other parameters when a high-speed train at a speed of 600 kilometers per hour passes through the platform to obtain the force analysis results, and determines the safe retreat distance based on the force analysis results. In this way, the characteristics of the coupled flow field structure between the train and the person 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 retreat distance for personnel can be quickly determined.

[0020] Optionally, the constructing of the train model and the human body model includes: Smooth the surface of the train and obtain the train's size information; Arrange N human models on the platform side close to the train, and arrange M measuring points along the height direction in the middle of the front of each human model, with a distance of Q cm between each adjacent measuring point; P measuring points are arranged at the place where there is no one beside the train but at the same height and lateral position as the measuring point of the human body model, P = M; A train model and a human body model are constructed based on the size information of the train, the N human body models, the M measuring points, and the P measuring points.

[0021] In this optional implementation, N is 5, M is 9, and Q is 20, which is only an example and not a limitation.

[0022] The determining of the calculation domain and boundary conditions according to the train model and the human body model includes: Determine the computational domain based on the train's dimensional information and set requirements; The overlapping grid method is used to simulate the relative movement between people and vehicles, and an overlapping area is set around the train, and the overlapping area moves forward according to the speed of the train; The outer surface of the overlapping area is set as the overlapping mesh boundary condition, the body surface of the train, the surface of the human body model, the ground and track corresponding to the calculation domain are set as the wall boundary conditions, and the side and top surfaces of the calculation domain are set as the free flow boundary conditions; The setting requirements include: Meet the full development of the flow field.

[0023] In one example, Figure 2 (a) is a schematic diagram of the train after smoothing, and Figure 2 (b) is a schematic diagram of the train model and the human body model. The train is a three-car formation. To facilitate numerical calculations, the details of the train surface are smoothed without affecting the calculation results. The train height is 4.20m, and the height is recorded as H as the characteristic dimension. The width of the train is 0.88H, and the total length of the train is 19.34H. For the convenience of calculation, a simplified human body model is used. Figure 3 (a) is a schematic diagram of the measurement points, and Figure 3 (b) is a schematic diagram of the measurement points of the human body model. Details such as facial features and limbs are ignored and only the general appearance is retained. The height of the human body model is 1.7m, which is 0.405H. The train runs on a double-track track with a track spacing of 5.1m. The train runs on the right side of the platform. The human models are arranged on the platform side close to the train. The first person is recorded as P1, 3m away from the center line of the right track. The next person is recorded as P2, and the distance from the right track increases by 0.5m, and increases by 10m along the direction of the train to ensure that adjacent human models do not affect each other. P3, P4, and P5 are arranged by analogy, and a total of 5 human models are arranged. In order to monitor the surface pressure and speed of the person, a measuring point is arranged every 20 cm in the height direction in the middle position of the front of the person, and a total of 9 measuring points are arranged. The surface measuring points of the first person are recorded as P1-1 to P1-9 from bottom to top, and the surface measuring points of the second person are recorded as P2-1 to P2-9 from bottom to top. In addition, the measuring points are arranged at the same height and lateral position as the surface measuring points of the person when there is no one beside the train, so as to facilitate the comparison of the difference in wind changes between when there is no one and when there is no one. The column corresponding to the surface measuring point of P1 is recorded as C1, and the measuring points are recorded as C1-1 to C1-9 from bottom to top. It is worth explaining that since the application adopts the numerical simulation method, the area of ​​the train running space simulated in the numerical simulation cannot be infinite. Therefore, a finite square area is used to represent the infinite space. When representing the infinite space, the six faces of the square calculation domain need to be given reasonable definitions, that is, boundary conditions, to ensure the accuracy of the simulation. Figure 4 As shown, 4-1 is the free flow 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 of the calculation area is set as the free flow boundary 4-1 to better simulate the flow of the flow field on both sides.

[0024] Specifically, the size of the computational domain is 142.9H×28.6H×16.7H, which can ensure the full development of the flow field. In numerical calculation, the overlapping grid method is used to simulate the relative motion between people and vehicles. An overlapping area is set around the train with a size of 36.9H×1.3H×1.4H, and the overlapping area moves forward according to the speed of the train. The outer surface of the overlapping area is set as an overlapping grid boundary condition, the surface of the car body, the surface of the human body, the ground of the computational domain and the track are set as wall boundary conditions, and the side and top surfaces of the computational domain are set as free flow boundary conditions, with a flow velocity of 0.

[0025] Optionally, the S2 includes: According to the calculation domain and boundary conditions, several layers of boundary layer grids are arranged on the train surface, and the growth rate and total thickness of the boundary layer grids are set; and the minimum size of the train grid, the minimum size of the human body model surface grid, the minimum size of the grid 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 are set.

[0026] In one example, if Figure 5 As shown in the figure, the cut volume mesh is used as the calculation mesh in this application: (a) is the train surface and surrounding ground mesh; (b) is the train surface boundary layer mesh; (c) is the human body surface and surrounding ground mesh; (d) is the human body surface boundary layer mesh. The train surface is arranged with 10 layers of boundary layer mesh, the boundary layer mesh growth rate is 1.2, the total thickness is 0.005mm, and the train surface Y+ range is as follows Figure 5 As shown, it meets the requirements of the numerical calculation method selected in this application. In order to more accurately calculate and capture the details of the flow field around the rear of the train and the human body, the corresponding areas are encrypted, the minimum grid size of the train surface is 0.0119H (0.005 / 0.42), the minimum grid size of the human body surface is 0.00595H, and the overlapping area size is 0.0476H (0.02mm). The total number of grids is 45.75 million, and the number of grids in the overlapping area is 17.25 million.

[0027] Optionally, 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 vehicle passes by, and record them 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; Obtain the negative pressure amplitude and the positive pressure amplitude of the flow field acting on the human body model when the tail vehicle passes by, and record them as the second negative pressure amplitude and the second positive pressure amplitude; determine the point c of the pressure distribution diagram according to the second negative pressure amplitude, and determine the point d of the pressure distribution diagram according to the second positive pressure amplitude; The final pressure distribution cloud map is determined based on the pressure values ​​on the four cross sections at points a, b, c and d.

[0028] The S5 includes: By analyzing the final pressure distribution cloud map, it is found that the positive pressure amplitude at point a is greater than the positive pressure amplitude at point d, and the negative pressure amplitude at point b is greater than the negative pressure amplitude at point c; according to the pressure values ​​of the cross sections at points a, c and d, it is obtained that the pressure in the lower half of the human body is greater than that in the upper half, and according to the pressure value of the cross section at point b, the pressure in the middle part of the human body is the greatest.

[0029] In this embodiment, the flow field structure analysis is performed as follows: In order to study the changes in the aerodynamic characteristics of people when the train passes by, people1 who is closest to the train is analyzed. The person is 3m away from the center line of the right track and 1.212m away from the edge of the platform. Figure 6 The pressure change on the surface of people1 when the train passes the platform and the pressure cloud map of the train when there is no one are used. The pressure change on the surface of people1 corresponds to their relative position on the train for analysis. Figure 6 In It refers to the negative pressure area of ​​the platform caused by the train passing through the head car of the platform. The minimum pressure extreme value appears here. Figure 7 By comparing the pressure changes of the human surface measuring point P1-5 and the corresponding unmanned measuring point C1-5, it can be found that the pressure changes are basically the same when there are people and when there are no people. Only when people pass by, the positive and negative pressure amplitudes of the human surface measuring point P1-5 are greater than those of the unmanned measuring point. Therefore, it is reasonable to analyze the human surface pressure characteristics when there are people using the cloud map around the train when there are no people. Figure 8 In the preferred embodiment of the present invention, 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.

[0030] It is worth noting that when the leading vehicle passes, there is first a positive pressure amplitude and then a negative pressure amplitude, which are Figure 6 In the middle, the positive pressure amplitude and the negative pressure amplitude should appear when the front of the train is about to pass the person and when the streamlined front of the train has not completely passed the person, respectively. The corresponding positions are as follows: Figure 6 As shown in the middle cloud diagram. When the middle car passes, the human body surface maintains a very small negative pressure value. When the rear car passes, the pressure change is similar to that when the front car passes. First, a negative pressure amplitude appears, and then a positive pressure amplitude appears, which are respectively Figure 6 Points (c) and (d) appear when the streamlined part of the rear vehicle passes by and after the rear of the vehicle passes by, respectively. Figure 6 As shown in the cloud diagram.

[0031] Pick Figure 6Further analysis is done on the pressure distribution cloud diagrams at the four cross sections (a), (b), (c), and (d). The positive pressure value at (a) is greater than the positive pressure value at (d), and the pressure radiates more widely in the lateral direction. 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 leading vehicle passes are greater than the pressure amplitudes when the trailing vehicle passes. This conclusion can also be drawn from Figure 7. In addition, it can be seen that the distribution characteristics of pressure in the height direction are Figure 6 At the three sections (a), (c), and (d) in the figure, the pressure on the lower part of the person is greater than that on the upper part. Figure 6 In the figure, the pressures of P1-5 and P1-1 are close and greater than those of P1-9. The pressure at point (b) is the highest in the middle of the human body because the platform limits the space and a vortex structure is generated on the side of the platform. At point (b), the vortex structure develops to the middle and lower part of the human body. Therefore, the pressure at point P1-5 is greater than that at point P1-1, which is greater than that at point P1-9.

[0032] Optionally, the S6 includes: The force analysis is performed with the train's forward direction as the positive X direction, the train platform side as the negative Y direction, and the train top as the positive Z direction; Analyze the force conditions of the human body model in the X direction and the Y direction when the leading vehicle and the trailing vehicle pass by respectively to obtain the force analysis results, which include the force of the human body model in the XY plane, the wind speed on the surface of the human body model, and the wind speed amplitude at the unmanned measuring point as the distance between the human body and the vehicle is changed; The safe retreat distance is calculated based on the force analysis results and safety threshold.

[0033] In this embodiment, the force analysis is performed based on the flow field analysis results as follows: like Fig. 9 As shown, the analysis of the flow field structure shows that the worst stage of the change of the pedestrian flow field structure is mainly concentrated when the front and rear of the vehicle pass by. Correspondingly, the end point analysis is performed on the human body force when the front and rear vehicles pass by. Fig. 9 In It refers to the negative pressure area of ​​the platform caused by the train passing through the head car on the platform. The minimum pressure extreme value occurs here.

[0034] For the convenience of analysis, the train's forward direction is taken as the positive X direction, the left side of the train is the positive Y direction, that is, the platform side is the negative direction, and the top of the train is the positive Z direction. Figure 11 (a) shows the force situation in the XY plane when the head car of the high-speed train passes by, and Figure 11 (b) shows the force situation in the XY plane when the tail car of the high-speed train passes by. Fig.10 It is the change in the force people are subjected to when trains pass by. When the first train passes by, people are subjected to a large force. When the middle train passes by, the force gradually decreases. When the last train passes by, people are subjected to a large force again, which is equal to that when the first train passes by, and then decreases.

[0035] Further analysis of the changing law of the force direction of people, Fig.10 This is the law of change of the component force on people1 when the car passes by, and the positions of the pressure amplitude (a)-(d) and the velocity amplitude (e)-(h) are marked in the figure. The force amplitude points can be matched with the positions in the cloud map for easy analysis.

[0036] It can be seen that the forces on the person are mainly in the X and Y directions, while the force in the Z direction is relatively small, with a maximum of about 30N. The position where the maximum value in the Z direction appears is not at the position where the person is subjected to the maximum total force, and has very little effect on the maximum value of the resultant force on the person. Therefore, in the subsequent analysis, the X and Y directions are mainly used. For the X direction, when the leading vehicle passes by, a small positive force of no more than 50N is first generated, pushing the person forward, and then quickly turns into a large reverse force of more than 100N. The (a)-(h) sections analyzed above correspond to the corresponding positions. The forward force appears around section (a), that is, the front of the vehicle is about to reach the position of the person. At this time, the front of the vehicle will expel the air in front, generating a positive pressure zone, which acts on the person as a forward force. The position where the maximum value of the negative force in the X direction appears is near section (e), which corresponds to the transition from positive pressure to negative pressure zone. There is positive pressure in front of the person and negative pressure behind the person, so a large backward force is generated on the person. After that, the force decreases to a very small value, and the force near the (f) section becomes 0, and a small reverse force is gradually generated. 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 the (a) section, pushing the person away from the car. Figure 6 It can be seen that this position is approximately at the junction of the positive pressure zone and the zero pressure zone. There is positive pressure in front of the person and negative pressure behind the person, and the person is subjected to a lateral force backward away from the car. After that, the Y-direction force drops rapidly to become a positive force, and fluctuates twice within the range of 0-70N. The range of positive force is approximately between sections (e) and (g), which just corresponds to the stage when the vortex on the platform develops and affects the person. At this time, there is a vortex area in front of the person, which is negative pressure, and the negative pressure behind the person is small, which generates a forward force and sucks the person toward the car. Take the time period when the force amplitude appears when the head car passes, 0.81s-0.9s, and draw the change in direction of the person in the XY plane as shown in Figure 12 (a). The whole process is mainly an outward and backward force, pushing the person outward. The force changes clockwise during the process, first increasing, then decreasing, and then increasing and then decreasing.

[0037] When the tail car passes by, the change in X-direction force is similar to that when the leading car passes by, but similar. First, there is a very small reverse force, followed by a large positive force, corresponding to the section at the maximum wind speed (h), approximately at the transition point from negative pressure to positive pressure, with negative pressure in front and positive pressure in the back, and a forward force, followed by a very small reverse force. After the (d) section, corresponding to the tail car passing by, the positive pressure in front is greater than the positive pressure in the back, and the force is backward. When the tail car passes by, the force in the Y direction is similar to that of the leading car but opposite, first a large positive force is generated, approximately near the (c) section, at this time there is a large negative pressure area in front of the person, and a smaller negative pressure behind the person, generating a forward force, sucking the person in the direction of the car. After that, the positive force drops rapidly and becomes a smaller reverse force, corresponding to the positive pressure area in the (d) section. Taking the force amplitude time period of 0.125-0.135 when the tail car passes by, the force magnitude and direction changes in the XY plane are plotted as shown in Figure 12 (b). During the whole process, the force is forward and inward, sucking people inward. During the process, the force changes clockwise, first increasing and then decreasing.

[0038] According to relevant standards, a force of 100N can be used as a safety threshold for human force. When the front and rear vehicles pass by, the force on each person exceeds 100N for a period of time, which puts them in a dangerous state. Therefore, it is necessary to increase the distance between people and vehicles to ensure their safety.

[0039] Specifically, Figure 12 (a) shows the force on people at different positions when the high-speed train passes through the platform at a speed of 600 km / h; Figure 12 (b) shows the surface wind speed of people at different positions when the high-speed train passes through the platform at a speed of 600 km / h; Figure 12 (c) shows the wind speed at the wind measurement point when the high-speed train passes through the platform at a speed of 600 km / h. First, three height measurement points are set on the human body model, namely height 1, height 5 and height 9. It can be seen from Figures 12 (a), 12 (b) and 12 (c) that with the increase of distance, the force on people or the wind speed has a significant decreasing trend, and the reduction effect is most obvious when the train is closer. Taking the force on people as an example, when the distance increases from 3m to 3.5m, the force on people decreases by 40.5N, a relative decrease of 29.2%. When the distance increases from 4.5 to 5m, the force on people decreases by 12N, a relative decrease of 20.9%. The wind speed at the human surface measurement point and the wind speed at the unmanned measurement point are both reduced, but their patterns are different. At the unmanned measurement point, the speed at height 5 at a distance of 3m is greater than that at height 1 and height 9, and the speed is the largest at the middle. After the distance increases to 3.5m, the coarseness of the three height measurement points is basically close, and the height 9 is slightly smaller, indicating that the farther the distance from the vehicle, the smaller the difference in wind speed in the height direction. The human surface measurement point is larger at 3m, and the wind speed at height 1 is greater than that at height 5 and height 9 at 3.5m and beyond. It may be due to the influence of people. At heights 5 and 9, the flow is hindered and the wind speed is smaller. Among them, Figure 13 (a) shows the force of people at different positions when the high-speed train passes through the platform at different speeds; Figure 13 (b) shows the human body surface wind speed of people at different positions when the high-speed train passes through the platform at different speeds; Figure 13 (c) shows the wind speed of wind measurement points at different positions when there are no people when the high-speed train passes through the platform at different speeds. It can be seen that the change patterns of the three aerodynamic data are similar, and they decrease with the decrease of vehicle speed, which is approximately linear. People1, who is closest to the car, has the most obvious decrease, while people2 and people3, who are farther away from the car, have a smaller decrease and are closer.

[0040] Further, based on the obtained data, the safe retreat distance of personnel is determined. There are many train wind safety standards. This application adopts the safety threshold value set as 100N force, 14m / s and 17m / s wind speed to determine the safe retreat distance of personnel, wherein Figure 14 (a) shows the relationship between the glide velocity and the distance from the center line of the track at different speeds, Figure 14 (b) shows the relationship between the human body surface wind speed and the distance from the center line of the track at different speeds, and Figure 14 (c) shows the relationship between the human body aerodynamic force and the distance from the center line of the track at different speeds. If the maximum human surface wind speed is used to judge, when the train is running at 600km / h, the safety distances obtained at 17m / s and 14m / s are 4.04m and 4.62m respectively. The current recommended high-speed rail safety distance in China is 3m from the center of the track. The distance obtained by this data is far more than 3m, and is 2.19m and 2.77m away from the edge of the platform. Considering the space limitations of the platform, this distance is obviously too large. For example, if the maximum speed of the train side point is selected, 17m / s and 14m / s are used as the speed limit to obtain the safety distance of 3.64m and 3.97m respectively. If the force on the person is used, the safety standard of 100N is used to solve the problem, and the minimum safety distance is 3.51m. The retreat distances obtained by different standards are all greater than the current safe retreat distance. The results obtained by using the speed beside the train and the force on the person are closer. According to the previous analysis, people have a greater impact on the flow field around the train, making the speed of the person surface greater than the speed of the corresponding position when there is no person. The safety distance obtained based on this data is relatively larger.

[0041] If the train speed is reduced to 550km / h and 500km / h, the safety distances obtained by using the trainside speeds of 17m / s and 14m / s are 3.80m and 3.61m respectively. Compared with 600km / h, the speed is reduced by 8.33% and 16.67%, and the safety distance is reduced by 4.28% and 9.07% respectively. Reducing the speed can significantly reduce the safety distance, but when the speed is reduced to 500km / h, the safety distance standard cannot be met. Therefore, in order to reduce the safety distance to a relatively low range, the speed needs to be reduced to a low enough level. The advantage of the train is its high running speed. If the speed is reduced too much when passing the platform, it will affect its operation, so comprehensive consideration is needed.

[0042] 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.

[0043] 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.

[0044] 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 retreat distance of personnel on a high-speed maglev railway platform, characterized in that: include: S1: constructing a train model and a human body model, and determining a calculation domain and boundary conditions according to the train model and the human body model; S2: determining a computational grid according to the computational domain and the boundary conditions, wherein the computational grid includes a train grid and a human body model surface grid; S3: determining a turbulence model according to the computational domain, the boundary conditions and the computational grid; S4: simulating the pressure amplitude on the surface of the human body when the train passes through the human body based on the train grid, the surface grid of the human body model, and the turbulence model, and determining a pressure distribution cloud map based on the pressure amplitude; S5: Performing flow field structure analysis based on the pressure distribution cloud map; S6: Performing a force analysis based on the flow field structure analysis result, and determining a safe retreat distance based on the force analysis result.

2. The method for determining the safe retreat distance for high-speed maglev railway platform personnel according to claim 1, characterized in that: The constructing of the train model and the human body model comprises: Smooth the surface of the train and obtain the train's size information; Arrange N human models on the platform side close to the train, and arrange M measuring points along the height direction in the middle of the front of each human model, with a distance of Q cm between each adjacent measuring point; P measuring points are arranged at the place where there is no one beside the train but at the same height and lateral position as the measuring point of the human body model, P = M; A train model and a human body model are constructed based on the size information of the train, the N human body models, the M measuring points, and the P measuring points.

3. The method for determining the safe retreat distance for high-speed maglev railway platform personnel according to claim 1, characterized in that: The determining of the calculation domain and boundary conditions according to the train model and the human body model includes: Determine the computational domain based on the train's dimensional information and set requirements; The overlapping grid method is used to simulate the relative movement between people and vehicles, and an overlapping area is set around the train, and the overlapping area moves forward according to the speed of the train; The outer surface of the overlapping area is set as the overlapping mesh boundary condition, the body surface of the train, the surface of the human body model, the ground and track corresponding to the calculation domain are set as the wall boundary conditions, and the side and top surfaces of the calculation domain are set as the free flow boundary conditions; The setting requirements include: Meet the development of flow field.

4. The method for determining the safe retreat distance for high-speed maglev railway platform personnel according to claim 1, characterized in that: The S2 includes: According to the calculation domain and boundary conditions, several layers of boundary layer grids are arranged on the train surface, and the growth rate and total thickness of the boundary layer grids are set; and the minimum size of the train grid, the minimum size of the human body model surface grid, the minimum size of the grid 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 are set.

5. The method for determining the safe retreat distance for high-speed maglev railway platform personnel 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 vehicle passes by, and record them 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; Obtain the negative pressure amplitude and the positive pressure amplitude of the flow field acting on the human body model when the tail vehicle passes by, and record them as the second negative pressure amplitude and the second positive pressure amplitude; determine the point c of the pressure distribution diagram according to the second negative pressure amplitude, and determine the point d of the pressure distribution diagram according to the second positive pressure amplitude; The final pressure distribution cloud map is determined based on the pressure values ​​on the four cross sections at points a, b, c and d.

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

7. The method for determining the safe retreat distance for high-speed maglev railway platform personnel according to claim 1, characterized in that: The S6 includes: The force analysis is performed with the train's forward direction as the positive X direction, the train platform side as the negative Y direction, and the train top as the positive Z direction; Analyze the force conditions of the human body model in the X direction and the Y direction when the leading vehicle and the trailing vehicle pass by, respectively, and obtain the force analysis results, which include the force of the human body model in the XY plane, the wind speed on the surface of the human body model, and the wind speed amplitude at the unmanned measuring point as the distance between the human body and the vehicle is changed; The safe retreat distance is calculated based on the force analysis results and safety threshold.

8. A system for determining the safe retreat distance of personnel on a high-speed maglev railway platform, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method described in any one of claims 1 to 7 are implemented.

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