Analysis Method for Snow Accumulation and Ice Formation on Train Bogies

Abstract

The present application provides a method for analyzing snow accumulation and icing on a train bogie. The method for analyzing snow accumulation and icing on the train bogie includes: establishing a three-dimensional model of the bogie and the car body of the train and performing mesh division on the three-dimensional model; setting up a flow field mathematical model for simulating the two-phase flow of air and ice and snow particles in the bogie area; setting up an ice and snow particle accumulation effect model for simulating the accumulation effect of ice and snow particles on the wall surface; setting initial conditions and boundary conditions; performing numerical simulation calculations on the accumulation situation of ice and snow particles in the air in the bogie area based on the flow field mathematical model and the ice and snow particle accumulation effect model; and post-processing the numerical simulation calculation results to analyze the snow accumulation situation in the bogie area. The method for analyzing snow accumulation and icing on the train bogie of the present application can achieve high-precision analysis of snow accumulation in the bogie area of high-speed trains.

Description

Technical Field

[0001] The present invention relates to the field of snow and ice accumulation analysis of train bogies, and particularly to a method for analyzing snow and ice accumulation on train bogies. Background Art

[0002] Rail transit systems have advantages such as low operating energy consumption, small floor area, and light environmental pollution, and play an important role in the comprehensive transportation system. Solving the problem of snow and ice accumulation in the bogie area is particularly crucial for the safe operation of rail vehicles. When a train runs in a snowstorm environment for a long time, the environmental wind carries snowflakes into the bogie. When there are many vortices in the movement stroke, the snowflakes adsorb to each other within the vortices and then adhere to the surface of nearby structures and accumulate. The flow field in the bogie area is disturbed by the accumulated snow, and the flow field structure changes, which exacerbates the formation of snow accumulation. In addition, a large amount of heat is generated when the braking device brakes, which will cause the snow on the bogie to melt, and the melted water quickly turns into ice. Elastic elements such as air springs and axle box springs in the bogie area will also generate heat during the movement of the train, causing the surrounding snow to melt and turn into ice. These additional ice on the bogie will increase the unsprung mass, deteriorate the elastic coefficient of the primary suspension springs, affect the dynamic performance of the vehicle, and threaten the safety of train operation. When the train runs under alpine conditions, it will cause large-area snow accumulation in the train bogie area, thus affecting the running stability of the train.

[0003] To solve the problem of snow and ice accumulation on the bogie, it is necessary to analyze the behavior of ice and snow particles in the air and the thermal and mechanical interaction relationships between ice and snow particles and the materials of the car body and bogie. At present, there is no such comprehensive calculation and analysis method at home and abroad. Generally, the air flow direction is qualitatively considered from the perspective of the flow field, so as to judge the possible places where ice and snow particles may accumulate. In addition, the mechanical behavior of snow accumulation particles and air is rarely considered in the domestic and foreign calculation methods, and there is no relevant calculation and analysis on the accumulation effect between ice and snow particles and bogie materials. Therefore, the current calculation and analysis methods have great limitations, and a more realistic method is to carry out a wind tunnel test on train snow and ice accumulation. However, first of all, there is no such wind tunnel in our country. Conducting a wind tunnel test abroad is not only costly but also time-consuming. In addition, the ice and snow particles created by the snow and ice accumulation wind tunnel are not exactly the same as those in the natural environment. Research shows that parameters such as the diameter, density, and humidity of ice and snow particles have an impact on the snow and ice accumulation on train bogies, especially the diameter of ice and snow particles. Since it directly affects several other parameters, it has a more significant impact on train snow and ice accumulation. The physical properties such as the diameter, density, and humidity of ice and snow particles in the actual natural environment are very complex. Therefore, it is urgent to develop a train anti-snow and ice accumulation analysis method for these characteristics of ice and snow particles to solve the problem of snow and ice accumulation on train bogies. Summary of the Invention

[0004] To address the deficiencies of the prior art, the present invention provides a method for analyzing snow accumulation and icing on a train bogie to solve the technical problem in the prior art of being unable to accurately analyze snow accumulation and icing on a train bogie.

[0005] To achieve the above object, the present application provides a method for analyzing snow accumulation and icing on a train bogie. The method for analyzing snow accumulation and icing on a train bogie includes: establishing a three-dimensional model of the bogie and the carbody of the train and performing mesh division on the three-dimensional model; setting a flow field mathematical model for simulating the air-ice and snow particle two-phase flow in the bogie area; setting an ice and snow particle accumulation effect model for simulating the accumulation effect of ice and snow particles on the wall surface; setting initial conditions and boundary conditions; performing numerical simulation calculations on the accumulation situation of ice and snow particles in the air in the bogie area based on the flow field mathematical model and the ice and snow particle accumulation effect model; and post-processing the numerical simulation calculation results to analyze the snow accumulation situation in the bogie area.

[0006] Further, setting the flow field mathematical model for simulating the air-ice and snow particle two-phase flow in the bogie area includes: setting a turbulence equation for simulating the air flow field in the bogie area; setting a resistance effect function of ice and snow particles in the air and a lift effect function of ice and snow particles in the air; and setting a Stokes function for describing the following behavior of ice and snow particles in the air.

[0007] Further, performing numerical simulation calculations on the accumulation situation of ice and snow particles in the air in the bogie area based on the flow field mathematical model and the ice and snow particle accumulation effect model includes: calculating the air flow field in the bogie area through the turbulence equation; calculating the resistance and lift forces received by the ice and snow particles in the air flow field through the resistance effect function and the lift effect function; calculating the movement trajectory of the ice and snow particles through the Stokes function; and calculating the snowflake flux of the ice and snow particles accumulated in the bogie area through the accumulation effect model.

[0008] Further, post-processing the numerical simulation calculation results to analyze the snow accumulation situation in the bogie area includes: summing the snowflake fluxes of each sub-time step to obtain the snow accumulation amount within the sub-time step; and summing the snowflake fluxes within the calculation time to obtain the total snow accumulation amount within the calculation time.

[0009] Further, setting the initial conditions and boundary conditions includes setting the initial particle size of randomly distributed ice and snow particles at the inlet.

[0010] Further, setting the ice and snow particle accumulation effect model for simulating the accumulation effect of ice and snow particles on the wall surface includes setting the snow accumulation coefficient of the materials of the carbody and the bogie under different physical characteristics of snowflakes.

[0011] Further, the snow accumulation coefficient is determined by determining the collision coefficient, adhesion coefficient, and accretion coefficient.

[0012] Further, setting the drag effect function of ice and snow particles in the air and the lift effect function of ice and snow particles in the air includes setting the drag coefficient of ice and snow particles and the lift coefficient of ice and snow particles.

[0013] Further, the drag coefficient of the ice and snow particles is set according to the relative Reynolds number of the ice and snow particles.

[0014] Further, the turbulence equation is the κ-ω turbulence equation, and the two-equation Y+ mode is adopted near the wall surface.

[0015] The present application proposes a mathematical analysis model based on the interaction of snow particles with different physical properties with air, various materials of the train, and the ground, considering the particle distribution law of different snow particles, the drag effect, lift effect, behavior law of ice and snow particles in the air, and the accumulation effect of ice and snow particles with the materials related to the train bogie. It can realize the analysis of train snow accumulation and icing under different speeds, different states, and different operating environment conditions. It can not only analyze the key parts of train snow accumulation and icing, but also accurately calculate the snow accumulation and icing amounts at these parts, realize the accurate calculation of the snow accumulation and icing amounts at each part of the bogie, so as to carry out optimized design for the snow accumulation and icing at the key parts of the bogie, reduce the design cycle, and provide an optimized design scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0017] Figure 1 Shows a flowchart of a method for analyzing snow accumulation and icing on a train bogie according to an embodiment of this application.

[0018] Figure 2 Shows a schematic diagram of the drag force received by ice and snow particles.

[0019] Figure 3 Shows a schematic diagram of the lift force received by ice and snow particles.

[0020] Figure 4 Shows a schematic diagram of the accumulation effect of ice and snow particles.

[0021] Figure 5 Shows the accumulation coefficient of snow against the bogie material determined through experiments within a certain temperature range. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments of the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the said technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0025] The present application provides a method for analyzing snow accumulation and icing on a train bogie, characterized in that the method for analyzing snow accumulation and icing on a train bogie includes:

[0026] S110: Establish a three-dimensional model of the bogie and the car body of the train and perform mesh division on the three-dimensional model;

[0027] S120: Set up a flow field mathematical model for the two-phase flow of air-ice and snow particles in the simulated bogie area;

[0028] S130: Set up an ice and snow particle accumulation effect model for simulating the accumulation effect of ice and snow particles on the wall surface;

[0029] S140: Set initial conditions and boundary conditions;

[0030] S150: Numerically simulate and calculate the accumulation of ice and snow particles in the bogie area during their movement in the air based on the flow field mathematical model and the ice and snow particle accumulation effect model;

[0031] S160: Post-process the results of the numerical simulation calculation to analyze the snow accumulation in the bogie area.

[0032] This application proposes a mathematical analysis model based on the interaction of ice and snow particles with different physical properties with air, various materials of the train, and the ground, considering the particle distribution law of different ice and snow particles, the drag effect, lift effect, behavior law of ice and snow particles in the air, and the accumulation effect of ice and snow particles with the materials related to the train bogie. It can realize the analysis of train snow and ice accumulation under different speeds, different states, and different operating environment conditions. It can not only analyze the key parts of train snow and ice accumulation, but also accurately calculate the amount of snow and ice accumulation in these parts, realize the accurate calculation of the amount of snow and ice accumulation in each part of the bogie, so as to carry out optimized design for the snow and ice accumulation in the key parts of the bogie, reduce the design cycle, and provide an optimized design scheme.

[0033] Next, refer to Figures 1-5 to describe in detail each step of the train bogie snow and ice accumulation analysis method according to the embodiments of the present application.

[0034] In step S110, a three-dimensional model of the train bogie and car body is established and the three-dimensional model is meshed. Specifically, step S110 may include:

[0035] S111: Establish a detailed three-dimensional model of the bogie and car body;

[0036] S112: Establish a surface mesh model;

[0037] S113: Establish a volume mesh, set volume mesh parameters, and determine the computational domain.

[0038] In step S111, a detailed three-dimensional model of the train bogie can be established through 3D software such as CATIA or PROE. When establishing the three-dimensional model, various fine structures of the bogie should be considered, including cables, hoses, etc. at the bottom of the bogie;

[0039] In step S112, a train bogie surface mesh model is established. In order to conduct an accurate analysis of snow and ice accumulation on the bogie, it is necessary to consider all structures of the train bogie, so it is necessary to establish a surface mesh for all parts of the train bogie. The discrete scale of the mesh can be specifically considered according to the size of the parts, and the specific requirement is that it cannot be distorted. For example, in a specific example, for the surface of a cable structure with a diameter of 5mm, the mesh size is guaranteed to be 0.5mm; for parts with larger curved surfaces such as empty springs, the mesh size is guaranteed to be 1mm; in order to control the scale of the mesh, in larger areas such as frame parts, these parts are relatively smooth, and the mesh size can be controlled at 5mm;

[0040] In step S113, the density of the grid can be planned according to the flow characteristics and geometric structure, and the grids of the parts with large curvature changes and key areas are encrypted to meet the grid requirements of such problems and ensure the simulation accuracy. Since the contact behavior of ice and snow particles with the bogie must be considered, and the movement trajectory of ice and snow particles in space and the movement characteristics with air must be captured, the volume grid size in the bogie area where ice and snow particles may move must be smaller than the diameter of the ice and snow particles. For example, according to the statistics of the distribution law of ice and snow particle diameter in a certain area, the volume grid size is set to 0.2mm, which can capture the movement trajectory and state of the smallest snow particles.

[0041] In step S120, a flow field mathematical model for simulating the air-ice and snow particle two-phase flow in the bogie area is set. The fluid flowing in the bogie area includes air and ice and snow particles mixed in the air. In the present application, the air is regarded as a continuous phase, and the ice and snow particles are regarded as a discrete phase, so as to establish an air-ice and snow particle two-phase flow model. Specifically, in one embodiment, a turbulence model is used to simulate the air flow field, and the mechanical action and following behavior between the ice and snow particles and the air flow field are simulated by the drag effect function, the lift effect function and the Stokes function. In this embodiment, step S120 includes:

[0042] S121: Setting turbulence equations for simulating the air flow field in the bogie area;

[0043] S122: Setting a drag effect function of ice and snow particles in the air and a lift effect function of ice and snow particles in the air; and

[0044] S123: Set the Stokes function that describes the following behavior of ice and snow particles in the air.

[0045] In step S121, a turbulence equation is defined to simulate the complex flow field structure in the bogie region. For example, in one embodiment, a κ-ω turbulence equation may be selected, and a two-equation Y+ mode is adopted near the wall.

[0046] In S122, assuming that the ice and snow particles are similar to solid spherical particles with a smooth surface, the equation of motion of the ice and snow particles is the basic mechanical equation:

[0047]

[0048] Where, is any kind of force acting on the ice and snow particles, m p is the mass of the ice and snow particles, is the acceleration of the ice and snow particles. Therefore, the drag and lift functions of the ice and snow particles can be obtained accordingly.

[0049] In one embodiment, the drag effect function of the ice and snow particles in the air is given by formula (2), and its force type is shown in Figure 2 ;

[0050]

[0051] Where is the drag force received by the ice and snow particles in the air flow field, ρ f is the oncoming flow density, S is the frontal area of a single ice and snow particle, is the relative velocity of the ice and snow particles and the oncoming flow, C d is the drag coefficient of a single ice and snow particle;

[0052] In one embodiment, the drag coefficient C in the drag effect function d is given according to the Reynolds number Re p of the ice and snow particles and the diameter of the particles. The judgment formula is that the relative Reynolds number of the ice and snow particles is

[0053]

[0054] Where is the relative velocity of the ice and snow particles and the oncoming flow, v f is the kinematic viscosity of the oncoming flow, d p is the diameter of the ice and snow particles.

[0055] The relationship between the relative Reynolds number and the drag coefficient of the ice and snow particles is:

[0056] Re p ≤1 C d =24 / Re p (4)

[0057]

[0058] 1000<Re p C d =0.44 (6)

[0059] In one embodiment, the lift force of ice and snow particles in the air is exerted by as given, and its force type is shown in Figure 3 , where is the lift force that ice and snow particles receive in the air flow field, m p is the mass of ice and snow particles, is the relative velocity between ice and snow particles and the oncoming flow, is the rotational velocity of ice and snow particles, C lm is the lift coefficient of ice and snow particles. Assuming that ice and snow particles are similar to solid spherical particles with a smooth surface, accordingly C lm can take 0.33.

[0060] In step S123, the Stokes function describes the behavior of ice and snow particles in the air flow field. In one embodiment, the Stokes function is given by function (7).

[0061]

[0062] where, m p is the mass of ice and snow particles, is the velocity of ice and snow particles, ρ f is the density of the oncoming flow, S is the frontal area of a single ice and snow particle facing the wind, is the velocity of the oncoming flow, C d is the drag coefficient of a single ice and snow particle.

[0063] The Stokes function characterizes the ratio of the inertial effect to the diffusion effect of ice and snow particles in the flow field. The smaller its value, the smaller the inertia of ice and snow particles and the easier it is to move with the air; conversely, the larger the value, the less obvious the followability of ice and snow particles moving with the air.

[0064] The aforementioned Stokes function can be equivalent to equation (8),

[0065]

[0066] The form of the solution can be written as:

[0067]

[0068] where, τ p is the relaxation time of ice and snow particles.

[0069] The momentum equation of ice and snow particles can be written as:

[0070]

[0071] Through the above equations, various mechanical behaviors of ice and snow particles in the air can be described.

[0072] Compared with the prior art, the above-mentioned flow field mathematical model of the present application takes into account the mechanical behavior of ice and snow particles in the air, especially the resistance effect, lift effect and behavior law of ice and snow particles in the air, thereby improving the accuracy of the model.

[0073] In step S130, an ice and snow particle accumulation effect model for simulating the accumulation effect of ice and snow particles on the wall surface is set. The ice and snow particle accumulation effect model mainly considers that when ice and snow particles move in the air and encounter a bogie or a car body structure, they will collide, bounce, cross, etc. It is necessary to focus on the accumulation effect of ice and snow particles on the frame. Figure 4 It is a typical effect diagram of particle accumulation effect.

[0074] In one embodiment, the expression form of the ice and snow particle accumulation effect model is:

[0075]

[0076] Among them, this accumulation effect model takes into account the influence of aerodynamics, mechanics and heat on the accumulation of snow on the bogie, and it is synthesized by three dimensionless coefficients. The accumulation coefficient β 123 is the product of the collision coefficient η1, the adhesion coefficient η2 and the accretion coefficient η3. Among them, the collision coefficient η1 takes into account the aerodynamic effect, the adhesion coefficient η2 takes into account the mechanical effect, and the accretion coefficient η3 takes into account the thermal effect of ice and snow particles.

[0077] Among them, m acc represents the mass of the snow accumulated and adhered on the bogie, and m inc represents the input amount of snow. The parameters of η1, η2, and η3 can be obtained through experiments.

[0078] In one embodiment, the method for obtaining the parameters of η1, η2, and η3 through experiments is obtained through an equation, and the form of the equation is:

[0079] m imp = m inc ·η1 (12)

[0080] m stick = m inc ·η1·η2 (13)

[0081] m acc = m inc ·η1·η2η3 (14)

[0082] Among them, m imp is the mass of the rebounded snow, m stick is the mass of the adhered snow, and m acc is the mass of the finally accumulated snow.

[0083] Research shows that there is a direct relationship between the snow accumulation coefficient and the external temperature. Through experiments, this application has obtained the snow accumulation coefficient of snow on bogie materials within a certain temperature range. Refer to Figure 5 , in Figure 5 , the horizontal axis T represents temperature, and the vertical axis β 123 represents the accumulation coefficient.

[0084] Compared with the prior art, the model of this application considers the accumulation effect of ice and snow particles related to bogie materials, thus improving the accuracy of the model.

[0085] In step S140, initial conditions and boundary conditions are set. Specifically, setting the initial conditions may include setting the running state of the train, setting the Lagrangian parameters of ice and snow particles, etc. Setting the running state of the train includes setting the initial running speed, acceleration, running trajectory, environmental temperature, etc. Setting the Lagrangian parameters of ice and snow particles can simulate the input of the snow accumulation amount, and the wind tunnel input amount or the real environmental snowfall amount measured according to meteorology can be selected; information such as the humidity, viscosity, and density of snow particles is input; among them, these physical property parameters of ice and snow particles can be obtained through experiments. Setting the initial conditions and boundary conditions may also include setting the particle size distribution of ice and snow particles at the entrance. In one embodiment, the particle size distribution of ice and snow particles at the entrance is set as a random distribution. Specifically, the initial radius of the random distribution of ice and snow particles is considered to follow for χ 2 , and its distribution function is In the formula, is the radius averaged by the mesh of snow particles, which can be obtained by sampling a snow sample in a certain place. For χ 2 distribution, the relationship between r and the Sauter mean radius is and r 32 / 3 is determined as the input quantity.

[0086] Define the distribution function g(r) of snowfall as:

[0087]

[0088] Randomly select the radius of ice and snow particles according to the probability density g(r). First, calculate the cumulative probability of g(r), and then convert h(r) into a random number uniformly distributed in the interval (0, 1).

[0089]

[0090] Since Select the ice and snow particle sample as N, then the bandwidth Let X be a random number between the intervals (0, 1), then the corresponding number n can be obtained to satisfy:

[0091]

[0092] Thus, the corresponding ice and snow particles are as follows:

[0093]

[0094] In practice, when setting the initial particle size of randomly distributed ice and snow particles, sample parameters of the ice and snow particle radius can be input, including the size of the ice and snow particle radius and the number of particles at each different radius. After inputting these parameters, according to the ice and snow particle radius distribution is automatically calculated.

[0095] In the prior art, usually only the radius of ice and snow particles is regarded as uniformly distributed, without considering the particle distribution law of different snow particles. However, the method for analyzing snow accumulation and icing on the train bogie of this application takes into account the particle distribution law of different snow particles, thus being closer to the ice and snow particles in the natural environment and improving the accuracy of the analysis.

[0096] In step S150, based on the flow field mathematical model and the ice and snow particle accumulation effect model, a numerical simulation calculation is carried out on the accumulation situation of ice and snow particles in the bogie area during their movement in the air. In one embodiment, a numerical simulation method is used to solve the flow field mathematical model and the ice and snow particle accumulation effect model, so as to realize the transient calculation of the movement of ice and snow particles in the air and their accumulation situation in the bogie area. A segregated solver can be selected to solve the flow field mathematical model and the ice and snow particle accumulation effect model. In one embodiment, step S150 includes:

[0097] S151: Calculate the air flow field in the bogie area through the turbulence equation;

[0098] S152: Calculate the resistance and lift forces received by the ice and snow particles in the air flow field through the resistance effect function and the lift effect function;

[0099] S153: Calculate the movement trajectory of the ice and snow particles through the Stokes function;

[0100] S154: Calculate the snowflake flux of the ice and snow particles accumulated in the bogie area through the accumulation effect model.

[0101] In step S160, post-processing is performed on the numerical simulation calculation results to analyze the snow accumulation situation in the bogie area. In one embodiment, step S160 may include:

[0102] S161: Sum the snowflake fluxes of each sub-time step to obtain the snow accumulation amount within the sub-time step; and

[0103] S162: Sum the snowflake fluxes within the calculation time to obtain the total snow accumulation amount within the calculation time.

[0104] Step S162 includes:

[0105] S1621: Calculate the snow accumulation amount in each calculation period for different parts, that is, select different parts of the car body or bogie, sum the snowflake fluxes of different categories (different in size, humidity, and viscosity) at each moment, and output the snow accumulation amount at each moment for different parts;

[0106] S1622: Integrate the snow accumulation amounts of different parts at each moment to obtain the total snow accumulation amount.

[0107] In one embodiment, step S160 may further include displaying a snow accumulation amount cloud map. Specifically, when selecting a scalar cloud map display, the snow accumulation amount at each moment can be selected, and the total snow accumulation amount for the total calculation time can be selected. Through the snow accumulation amount cloud map, the snow accumulation conditions of each part can be visually displayed, so as to conduct targeted improvement and optimization.

[0108] This application uses a probability distribution function to simulate the spatial distribution law of snow particles with different particle sizes; establishes a mathematical model of ice and snow particles in the air including resistance and lift; uses the Stokes function to describe the behavior of snow accumulation particles in the flow field, and determines the form of the relaxation time parameter solution of ice and snow particles; establishes a snow accumulation particle stacking effect model; and determines the analysis process of train snow accumulation and icing. The train bogie snow accumulation and icing analysis method of this application realizes high-precision analysis of snow accumulation in the bogie area of high-speed trains.

[0109] It should be understood that the above-mentioned various steps or sub-steps are not necessarily executed in sequence one by one. Unless there is a clear description in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the above steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least a part of other steps or sub-steps or stages of other steps.

[0110] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not conflict, it should be considered as the scope recorded in this specification.

[0111] The above is only the preferred embodiment of this application and is not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A method for analyzing snow accumulation and icing on a train bogie, characterized in that, The snow and ice accumulation analysis method for the train bogie includes: Establish a three-dimensional model of the bogie and the carbody of the train and perform mesh division on the three-dimensional model; Set up a flow field mathematical model for the air-ice and snow particle two-phase flow in the simulated bogie area; Set up an ice and snow particle accumulation effect model for simulating the accumulation effect of ice and snow particles on the wall surface; Set initial conditions and boundary conditions; Based on the flow field mathematical model and the ice and snow particle accumulation effect model, perform numerical simulation calculations on the accumulation situation of ice and snow particles in the bogie area when moving in the air; Post-process the numerical simulation calculation results to analyze the snow accumulation situation in the bogie area; Among them, setting up a flow field mathematical model for the air-ice and snow particle two-phase flow in the simulated bogie area includes: Set up a turbulence equation for the air flow field in the simulated bogie area; Set up a drag effect function of ice and snow particles in the air and a lift effect function of ice and snow particles in the air; And set up a Stokes function for describing the following behavior of ice and snow particles in the air; Among them, the turbulence equation is the κ-ω turbulence equation, and the two-equation Y+ mode is adopted near the wall surface; Among them, the drag effect function of ice and snow particles in the air is: Among them, is the resistance suffered by ice and snow particles in the air flow field, ρ f is the oncoming flow density, S is the cross-sectional area of a single ice and snow particle facing the oncoming flow, is the relative velocity between the ice and snow particles and the oncoming flow, C d is the drag coefficient of a single ice and snow particle; Among them, the lift effect function of ice and snow particles in the air is: Among them, is the lift force exerted on the ice and snow particles in the air flow field, m p is the mass of the ice and snow particles, is the relative velocity of the ice and snow particles with respect to the oncoming flow, is the rotational velocity of the ice and snow particles, C lm is the lift coefficient of the ice and snow particles; Among them, the expression form of the ice and snow particle accumulation effect model is: Among them, the accumulation coefficient β 123 is the product of the collision coefficient η1, the adhesion coefficient η2, and the accretion coefficient η3. The collision coefficient η1 takes into account the aerodynamic effect, the adhesion coefficient η2 takes into account the mechanical effect, and the accretion coefficient η3 takes into account the thermal effect of ice and snow particles; among them, m acc represents the mass of snow accumulated and adhered on the bogie, and m inc represents the input amount of snow.

2. The method for analyzing snow accumulation and icing on a train bogie according to claim 1, wherein Based on the flow field mathematical model and the ice and snow particle accumulation effect model, performing numerical simulation calculations on the accumulation situation of ice and snow particles in the bogie area when moving in the air includes: Calculate the air flow field in the bogie area through the turbulence equation; Calculate the drag and lift forces received by the ice and snow particles in the air flow field through the drag effect function and the lift effect function; Calculate the movement trajectory of the ice and snow particles through the Stokes function; Calculate the snowflake flux of the ice and snow particles accumulated in the bogie area through the accumulation effect model.

3. The train bogie snow and ice accumulation analysis method according to claim 2, wherein, Post-processing the numerical simulation calculation results to analyze the snow accumulation situation in the bogie area includes: Sum the snowflake fluxes of each sub-time step to obtain the snow accumulation amount within the sub-time step; And sum the snowflake fluxes within the calculation time to obtain the total snow accumulation amount within the calculation time.

4. The snow and ice accumulation analysis method for a train bogie according to claim 1, characterized in that Setting initial conditions and boundary conditions includes setting the initial particle size of randomly distributed ice and snow particles at the inlet.

5. The snow and ice accumulation analysis method for a train bogie according to claim 1, characterized in that The drag coefficient of the ice and snow particles is set according to the relative Reynolds number of the ice and snow particles.

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