Simulation method and system for interaction of dust collection airflow and abrasive dust of rail grinding wagon

Abstract

The invention provides a simulation method and system for interaction of dust collection airflow and abrasive dust of a steel rail grinding wagon, and the method comprises the steps: firstly, constructing an internal and external flow field model of a grinding dust collection device through a computational fluid dynamics method; secondly, establishing a discrete particle model capable of reflecting morphological characteristics of the abrasive dust by using a discrete element method, and defining deposition judgment criteria of the abrasive dust in the vehicle body and on wall surfaces such as a track plate; finally, on the basis of a discrete element and computational fluid dynamics coupling method, continuous phase and discrete phase information is interactively updated, and interaction of abrasive dust and dust collection airflow is simulated. According to the method and the system provided by the invention, the migration, agglomeration and deposition behaviors of the grinding dust under the action of the dust collection airflow are accurately captured for the first time; the dynamic real-time adjustment of the flow field characteristics under the influence of abrasive dust agglomeration and deposition is realized for the first time; macro-micro multi-scale simulation of interaction of dust collection airflow and abrasive dust under the real working condition of the grinding dust collection unit of the steel rail grinding wagon is realized for the first time.

Description

Technical Field

[0001] The invention relates to the technical field of railway maintenance, and in particular to a method and system for simulating the interaction between dust collecting airflow and grinding chips of a rail grinding vehicle. Background Art

[0002] In the daily maintenance of railways, regular grinding with rail grinding vehicles is one of the effective means to eliminate rail wear and rolling contact fatigue. my country has more than 160,000 kilometers of operating lines, which need to be polished in time according to the development of rail diseases, especially for high-speed railways with strict requirements on smoothness. Therefore, as the demand for daily grinding of lines continues to rise, the operating efficiency of rail grinding vehicles directly affects the safe operation of railway lines.

[0003] During the operation of the grinding car, a large amount of grinding chips will be generated when the grinding stone grinds the rails. How to efficiently collect these grinding chips is crucial to the efficiency of mechanical operation. At present, the dust collection device on the grinding car is generally used to collect the grinding chips simultaneously during operation. However, due to the low dust collection efficiency of existing equipment, nearly 80% of the grinding chips cannot be effectively collected. During operation, the uncollected grinding chips adhere to the internal machinery, which can easily cause problems such as grinding motor jamming and high temperature failure, resulting in a high failure rate of the grinding car. In addition, a large amount of grinding chips remain on the surface of the track after the operation, which requires a lot of manpower and material resources to clean up, greatly limiting the effective operation time of the grinding car during the window period.

[0004] At present, the simulation method used to explore the dust collection performance of mechanical devices is mainly computational fluid dynamics (CFD). CFD simulates fluid flow behavior by numerically solving the Navier-Stokes equations. It can accurately simulate the complex flow field characteristics inside the dust collection device and has the advantages of high efficiency and flexibility. Research on the dust collection performance of grinding vehicles is still in its infancy. Only a few scholars have used CFD simulation to explore the flow field characteristics such as pressure and flow velocity inside the dust collection device, but the migration law of grinding chips under dust collection conditions has not been touched. In addition, in the design of dust collection devices in the fields of powder handling and mining, some scholars have developed a discrete phase particle model (DPM) based on CFD to achieve a simplified simulation of dust. By simplifying the powder particles into spherical particles, their motion trajectories in the flow field are calculated. Although this method takes into account the migration of dust in the dust collection flow field, it cannot accurately simulate the complex behaviors of particles such as agglomeration and deposition under the action of airflow.

[0005] The simulation method used to simulate the microscopic behavior of discrete wear chips is mainly based on the discrete element method (DEM). DEM describes the movement and accumulation behavior of discrete particles in detail by calculating the interactions between particles and between particles and walls, such as collision and friction. It is suitable for exploring the diffusion and micromechanical effects of particle systems. Existing studies have used DEM to conduct in-depth analysis of the splashing and accumulation behavior of wear chips of different shapes and types during the grinding process. However, systematic research on the macro- and micro-interactions between wear chips and airflow under dust collection conditions is still relatively scarce. Summary of the invention

[0006] The embodiments of the present invention provide a method and system for simulating the interaction between dust collecting airflow and grinding chips of a rail grinding vehicle, which are used to solve the problems existing in the prior art.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme.

[0008] The simulation method of the interaction between the dust collecting airflow and the grinding debris of the rail grinding vehicle includes:

[0009] S1 constructs the internal and external flow field model of the grinding dust collection device by computational fluid dynamics method;

[0010] S2 uses the discrete element method to construct a discrete particle model that can reflect the morphological characteristics of wear debris, and defines the criteria for the deposition of wear debris on the interior of the vehicle body and the wall surface such as the track plate;

[0011] S3 is based on the bidirectional coupling method of discrete element and computational fluid dynamics. It simulates the interaction between the dust collection airflow and the grinding chips by exchanging and updating data between the internal and external flow field models of the grinding dust collection device and the discrete particle model.

[0012] Preferably, step S1 comprises:

[0013] S11 treats the fluid as a continuous phase and describes the flow characteristics of the fluid through the Navier-Stokes equations in the Euler coordinate system.

[0014]

[0015] Solve; where ρ is the airflow density; t is the flow time; u is the airflow velocity in the absolute coordinate system; i is the tensor symbol; μ is the airflow viscosity; δ ij is the Kronecker function, which is 1 when i=j and 0 otherwise;

[0016] S12 is based on the calculation results of sub-step S11, and by assuming that the air in the flow field is an incompressible fluid, defining the track plate and the body structure as wall boundary conditions, defining the dust collection suction port as the velocity outlet, and defining the outer edge boundary surface of the calculation domain as a pressure inlet with a standard atmospheric pressure, the flow field and the geometric body are divided into unstructured grids using meshing software, and the grid is encrypted in the slits between the grinding motors and between the track plate and the body fire curtain. The grid grinding chips with the highest computational efficiency are selected through the grid independence test to construct the internal and external flow field model of the grinding dust collection device.

[0017] Preferably, step S2 comprises:

[0018] S21 uses discrete element method to flexibly model the strip, blade, flake and spherical grinding chips produced by rail end face grinding;

[0019] S22 is calculated by the force balance of particles in the Lagrangian coordinate system.

[0020]

[0021] Calculate the motion parameters of the wear debris in the dust collecting flow field; where m p is the particle mass, is the air velocity at the particle location, is the particle velocity, ρ p is the particle mass, For additional force, represents the fluid drag, τ r The relaxation time of the wear debris is calculated by the following formula (4):

[0022]

[0023] In formula (4), μ is the molecular viscosity of the fluid, d p is the diameter of the wear particle, drag coefficient α 1 , α 2 and α 3 is a constant, Re is the Reynolds number, and the formula

[0024]

[0025] Calculate and obtain;

[0026] S23 pass-through

[0027]

[0028] Calculate the Saffman lift force on the migration and diffusion of wear debris particles; where N = 2.594, d ij is the deformation tensor;

[0029] S24 pass-through

[0030]

[0031] Calculate the critical deposition velocity; where R is the kinetic energy recovery coefficient of the collision, K is the effective stiffness of the collision, and the formula

[0032]

[0033] In formula (8), k w and k p Pass-through

[0034] and

[0035]

[0036] Calculated; In formulas (9) and (10), E w and E p are the Young's modulus of the collision wall and the wear debris, v w and v p is the Poisson's ratio of the wall and the wear debris;

[0037] S25 passes the relationship between the wear debris impact velocity and the critical deposition velocity

[0038]

[0039] Define the criteria for the deposition of wear debris on the interior of the vehicle body and on the wall surfaces such as the track plates.

[0040] Preferably, step S3 comprises:

[0041] S31 solves the velocity field, pressure field and turbulence characteristics of the fluid by polishing the internal and external flow field models of the dust collector and according to the set initial conditions;

[0042] S32 injects wear particles through the discrete particle model and solves the particle velocity and position information at a certain time step.

[0043] Pass the particle velocity and position information of this time step to the CFD model;

[0044] S33 calculates the volume fraction of the grid and the force of the flow field on the wear debris in a certain time step by polishing the flow field model inside and outside the dust collecting device and according to the flow field and particle information, and obtains the momentum exchange amount between the discrete phase wear debris particles and the continuous phase dust collecting airflow, and then updates the flow field information according to the momentum exchange amount;

[0045] S34 The CFD model transmits the calculation data of sub-step S33 to the discrete particle model, so that the discrete particle model performs the incidence, contact and deposition calculations of the wear debris in the next time step based on the received calculation data and updates the position information of the wear debris;

[0046] The steps S31 to S34 are repeatedly performed multiple times to simulate the interaction between the dust collecting airflow and the grinding debris.

[0047] In a second aspect, the present invention provides a simulation system for the interaction between dust collecting airflow and grinding debris of a rail grinding vehicle, comprising:

[0048] Modeling and analysis modules for:

[0049] The internal and external flow field model of the grinding dust collection device was constructed by computational fluid dynamics method;

[0050] A discrete particle model that can reflect the morphological characteristics of wear debris is constructed by discrete element method, and the criteria for determining the deposition of wear debris on the interior of the vehicle body and the wall surface of the track plate are defined;

[0051] Based on the bidirectional coupling method of discrete element and computational fluid dynamics, the interaction between the dust collecting airflow and the grinding debris is simulated by transferring data between the internal and external flow field models of the grinding dust collecting device and the discrete particle model.

[0052] The visualization output module is used to visualize the interaction between the simulated dust collection airflow and the wear debris.

[0053] It can be seen from the technical solutions provided by the above-mentioned embodiments of the present invention that the present invention provides a method and system for simulating the interaction between the dust-collecting airflow and the wear debris of a rail grinding vehicle, wherein the method comprises: first, constructing the internal and external flow field models of the grinding and dust-collecting device using the computational fluid dynamics method. Then, a discrete particle model that can reflect the morphological characteristics of the wear debris is established using the discrete element method, and the deposition judgment criteria of the wear debris on the interior of the vehicle body and the wall surfaces such as the track plate are defined. Finally, based on the coupling method of discrete elements and computational fluid dynamics, the continuous phase and discrete phase information are interactively updated to simulate the interaction between the wear debris and the dust-collecting airflow. The method and system provided by the present invention realize for the first time the accurate capture of the migration, agglomeration and deposition behavior of the grinding debris under the action of the dust-collecting airflow; for the first time, the dynamic real-time adjustment of the flow field characteristics under the influence of the wear debris agglomeration and deposition is realized; for the first time, the macroscopic and microscopic multi-scale simulation of the interaction between the dust-collecting airflow and the wear debris under the real working conditions of the grinding and dust-collecting unit of the rail grinding vehicle is realized.

[0054] Additional aspects and advantages of the present invention will be given in part in the following description, which will become obvious from the following description, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0056] Figure 1 A processing flow chart of a method for simulating the interaction between dust collecting airflow and grinding chips of a rail grinding vehicle provided by the present invention;

[0057] Figure 2 A schematic diagram of the internal and external flow field model of a grinding dust collection device for simulating the interaction between the dust collection airflow and grinding chips of a rail grinding vehicle provided by the present invention;

[0058] Figure 3 A schematic diagram of the morphology of grinding chips and a flexible simulation model of the simulation method for the interaction between the dust collecting airflow and grinding chips of the rail grinding vehicle provided by the present invention;

[0059] Figure 4 A schematic diagram of a discrete element and computational fluid dynamics coupling calculation flow of a simulation method for the interaction between dust collecting airflow and grinding chips of a rail grinding vehicle provided by the present invention;

[0060] Figure 5 A logic block diagram of a simulation system for the interaction between the dust collecting airflow and grinding chips of a rail grinding vehicle provided by the present invention. DETAILED DESCRIPTION

[0061] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0062] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "one", "said", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or coupling. The term "and / or" used herein includes any unit and all combinations of one or more associated listed items.

[0063] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0064] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each embodiment does not constitute a limitation on the embodiments of the present invention.

[0065] The present invention provides a method and system for simulating the interaction between dust collecting airflow and grinding chips of a rail grinding vehicle, which are used to solve the following technical problems existing in the prior art:

[0066] At present, the simulation methods for rail grinding vehicle grinding dust collection devices at home and abroad mainly have the following shortcomings:

[0067] (1) Computational fluid dynamics method:

[0068] Computational fluid dynamics can only simulate the flow field distribution inside and outside the grinding dust collection device in detail, and describe the changes in pressure and flow rate under different dust collection flow rates, but when dealing with abrasive particles, they can only be regarded as spherical particles. This simplification ignores the true shape of the abrasive particles, cannot accurately reflect the difference in fluid forces on abrasive particles of different shapes, and is even more difficult to characterize the complex microscopic mechanical behaviors such as the agglomeration effect of flexible strip abrasive particles and the near-wall collision deposition of abrasive particles.

[0069] (2) Discrete Element Method:

[0070] Although the discrete element method can effectively characterize the microscopic mechanical behavior of wear debris, especially in describing the migration, agglomeration and deposition behavior of wear debris, it has obvious limitations in dealing with complex boundaries and multi-scale flows. Due to the complex geometric structure of the internal and external flow fields where the dust collector is located, it is difficult for DEM to fully capture the flow details of the dust collection airflow at different locations. In addition, the discrete element simulation cannot dynamically adjust the flow field characteristics to reflect the influence of wear debris agglomeration and deposition on the flow state of the airflow, thus ignoring the macro-micro interaction between the dust collection airflow and the wear debris.

[0071] In order to overcome the above shortcomings, the present invention proposes a coupled simulation method for a grinding dust collection device based on discrete element and computational fluid dynamics coupling. This method can accurately depict the influence of the interaction between the dust collection airflow and the wear debris on the airflow flow characteristics and the migration, agglomeration and deposition characteristics of the wear debris, thereby improving the calculation accuracy and reliability of the simulation of the real working conditions of the grinding dust collection device.

[0072] In view of this, in-depth research on the flow field characteristics and the diffusion and deposition behavior of grinding chips under the interaction between the dust collection airflow inside the grinding car is of great significance for optimizing the internal structure of the grinding dust collection unit and improving the operating efficiency of the rail grinding car.

[0073] See also Figure 1 The present invention provides a method for simulating the interaction between dust collecting airflow and grinding debris of a rail grinding vehicle, comprising:

[0074] S1 constructs the internal and external flow field model of the grinding dust collection device by computational fluid dynamics (CFD);

[0075] S2 uses the discrete element method to construct a discrete particle model (DEM) that can reflect the morphological characteristics of wear debris, and defines the criteria for the deposition of wear debris on the interior of the vehicle body and the wall surface such as the track plate;

[0076] S3 is based on the bidirectional coupling method of discrete element and computational fluid dynamics. It simulates the interaction between dust collection airflow and grinding chips by performing data transfer processing between the internal and external flow field models of the grinding dust collection device and the discrete particle model and updating the data in the model.

[0077] The simulation results are used to improve the design of the dust collection device of the rail grinding vehicle to enhance the dust collection efficiency.

[0078] The present invention adopts the discrete element method to establish a flexible wear chip model, and adopts the computational fluid dynamics method to establish the internal and external flow field model of the "grinding-dust collection" trolley. Based on the coupling transmission of the wear chip displacement and force information between the two, the refined simulation of the interaction between the dust collection airflow and the wear chips is realized. The present invention can provide scientific theoretical guidance for the research on the dust collection performance and structural optimization design of the grinding dust collection unit of the rail grinding vehicle.

[0079] In the preferred embodiment provided by the present invention, the specific process of each step is as follows.

[0080] 1. Continuous phase modeling of dust collection flow field:

[0081] The present invention is based on the computational fluid dynamics method, and the fluid is regarded as a continuous phase for calculation. Its flow characteristics are solved by the Navier-Stokes equations in the Euler coordinate system. Considering that turbulence will form at the corners and slits inside the car body, in order to balance the calculation accuracy and time, the k-ε turbulence model is selected for simulation. The continuity equation and momentum equation of the airflow are as follows:

[0082]

[0083] Where ρ is the airflow density; t is the flow time; u is the airflow velocity in the absolute coordinate system; i is the tensor symbol; μ is the airflow viscosity; δ ij is the Kronecker function, which is 1 when i=j and 0 otherwise.

[0084] Based on the above formula, the geometric model of the internal and external flow fields of the dust collector is established by appropriate simplification, such as Figure 2 As shown in the figure, the corresponding numbers are: 1-fluid calculation domain; 2-dust collection air intake; 3-pressure inlet; 4-incompressible air flow; 5-grinding chip ejection source; 6-car body wall; 7-track plate wall. In the model, a certain range of calculation domain is selected to ensure that the air flow is fully expanded. Assuming that the air in the flow field is an incompressible fluid, the track plate and the car body structure are defined as wall boundary conditions, the dust collection air intake is defined as a velocity outlet, and the outer edge boundary surface of the calculation domain is defined as a pressure inlet with a standard atmospheric pressure. The flow field and geometry are divided into unstructured grids using meshing software, and the grids are encrypted at the slits between the grinding motors and between the track plate and the car body fire curtain. Finally, the grid chip with the highest computational efficiency is selected through the grid independence test to complete the establishment of the internal and external flow fields of the grinding dust collection device.

[0085] 2. Discrete phase modeling of grinding chips:

[0086] 1) Simulation model of wear chip flexibility

[0087] The present invention adopts the discrete element method to flexibly model the four forms of grinding chips generated by rail end surface grinding, namely, strip, blade, flake and spherical. Figure 3 As shown. The corresponding numbers in the figure are: A-strip-shaped wear debris; B-blade-shaped wear debris; C-flaky wear debris; D-spherical wear debris. Among them, the spherical wear debris is directly simulated using a single sphere, and its particle size distribution range is between 100 and 300μm; the flake, blade-shaped and strip-shaped wear debris are spliced ​​by multiple sub-particles, and each sub-particle is connected by a force bond to simulate the flexibility of the wear debris. The width of the strip-shaped wear debris is about 50 to 100μm, and the length ranges from 10000 to 15000μm; the blade-shaped wear debris is shorter and wider than the strip-shaped wear debris, with a width of about 100 to 200μm and a length of 2000 to 5000μm; the flake-shaped wear debris is close to a rectangle, and its side length is about 200 to 500μm. Through statistical analysis, the above four forms of chip particles were mixed according to the proportion of chips with different morphologies, among which spherical chips accounted for 70%, followed by flake chips, blade chips and strip chips, accounting for 15%, 10% and 5% respectively.

[0088] 2) Grinding chip motion control equation

[0089] The movement of the wear debris in the dust collection flow field is calculated by the force balance of the particles in the Lagrangian coordinate system, which includes the inertial force and the external force on the particles, as shown in the following formula:

[0090]

[0091] In the formula, mp is the particle mass, is the air velocity at the particle location, is the particle velocity, ρ p is the particle mass, For additional force, represents the fluid drag, τ r The relaxation time of the wear chips can be obtained by the following formula:

[0092]

[0093] Where μ is the molecular viscosity of the fluid, d p is the diameter of the wear particles, and Re is the Reynolds number, which is defined as follows:

[0094]

[0095] Drag coefficient α 1 , α 2 and α 3 is a constant.

[0096] When there is a significant velocity gradient in the airflow, uneven pressure distribution will occur on the surface of the wear debris particles. At this time, the wear debris will be subjected to a force perpendicular to the flow direction of the airflow, namely the Saffman lift. Since the shear stress and turbulent structure of the airflow inside the vehicle body are relatively complex. In this case, the Saffman lift has a significant effect on the migration and diffusion of wear debris particles. Therefore, in formula (3), the additional force needs to take into account the effect of the Saffman lift, which can be calculated by the following equation:

[0097]

[0098] Where, N = 2.594, d ij is the deformation tensor.

[0099] 3) Debris Deposition Determination Criteria

[0100] The applicant discovered in the experiment that in the semi-closed eddy flow area and the low flow velocity area, when the wear debris collides with the wall, due to the action of forces such as the van der Waals force, the tiny particles with a relatively low speed will produce a non-negligible deposition phenomenon on the wall. The deposition judgment criterion proposed in the present invention is based on the Johnson-Kendall-Roberts (JKR) theory, which determines whether the particle will be deposited by comparing the relationship between the incident velocity of the particle in the normal direction of the wall and the critical deposition velocity. Specifically, when the normal incident velocity of the particle is greater than the critical deposition velocity, the particle rebounds from the wall and re-enters the flow field to move; otherwise, the particle is deposited on the wall. The critical deposition velocity is related to the characteristics of the particle and the wall, and can be expressed as:

[0101]

[0102] In the formula, K is the effective stiffness of the collision, and R is the kinetic energy recovery coefficient of the collision. Here, K is as follows:

[0103]

[0104] In the formula, k w and k p It can be found by the following formula:

[0105]

[0106] In the formula, E w and E p are the Young's modulus of the collision wall and the wear debris, v w and v p is the Poisson's ratio of the wall and the wear debris.

[0107] Finally, the deposition criterion obtained based on the relationship between the wear debris incident velocity and the critical deposition velocity is as follows:

[0108]

[0109] 3. Continuous phase-discrete phase coupling model:

[0110] The present invention calculates the complex interaction between the continuous phase dust collection airflow and the discrete phase wear particles based on the two-way coupling method of discrete element and computational fluid dynamics. First, the CFD model solves the velocity field, pressure field and turbulence characteristics of the fluid according to the set initial conditions. Subsequently, the DEM model incidents the wear particles, solves the particle velocity and position information for a time step, and then passes it to the CFD model. The CFD model calculates the volume fraction of the grid and the force of the flow field on the wear particles in the time step based on the flow field and particle information, and obtains the momentum exchange between the two phases (discrete phase wear particles and continuous phase dust collection airflow) to update the flow field information. Further, the CFD model passes the wear force data to the DEM model for it to solve the movement of the wear particles in the next time step. At the same time, the DEM model performs the incidence, contact and deposition calculations of the wear particles in the next time step and updates the position information of the wear particles. At this point, the coupling calculation of one time step is completed. The above coupling calculation process is as follows. Figure 4 shown.

[0111] In a second aspect, the present invention provides a simulation system for the interaction between the dust collecting airflow and the grinding debris of a rail grinding vehicle, such as Figure 5 As shown, including:

[0112] Modeling and analysis module 501, used for:

[0113] The internal and external flow field model of the grinding dust collection device was constructed by computational fluid dynamics method;

[0114] A discrete particle model that can reflect the morphological characteristics of wear debris is constructed by discrete element method, and the criteria for determining the deposition of wear debris on the interior of the vehicle body and the wall surface of the track plate are defined;

[0115] Based on the bidirectional coupling method of discrete element and computational fluid dynamics, the interaction between the dust collecting airflow and the grinding debris is simulated by transferring data between the internal and external flow field models of the grinding dust collecting device and the discrete particle model.

[0116] The visualization output module 502 is used to visualize the interaction between the simulated dust collecting airflow and the wear debris.

[0117] In summary, the present invention provides a method and system for simulating the interaction between the dust-collecting airflow and the wear debris of a rail grinding vehicle, wherein the method comprises: first, constructing the internal and external flow field models of the grinding and dust-collecting device using computational fluid dynamics. Then, a discrete particle model that can reflect the morphological characteristics of the wear debris is established using the discrete element method, and the criteria for determining the deposition of the wear debris on the interior of the vehicle body and the wall surfaces such as the track plate are defined. Finally, based on the coupling method of discrete elements and computational fluid dynamics, the continuous phase and discrete phase information are interactively updated to simulate the interaction between the wear debris and the dust-collecting airflow. The method and system provided by the present invention have the following advantages:

[0118] (1) Detailed characterization of the migration, agglomeration and deposition behavior of wear debris under airflow

[0119] The coupling simulation method proposed in the present invention uses the discrete element method to flexibly model the wear debris particles of different morphologies, and can accurately simulate the morphological characteristics of the wear debris and the agglomeration behavior caused by its bending. Based on the JKR collision theory, a criterion for the near-wall deposition of wear debris is constructed, which comprehensively considers the elastic contact deformation and adhesion effect when the wear debris collides with the wall. Through the DEM-CFD coupling interface, the fluid force on the wear debris is transmitted and its motion state is updated, realizing the accurate capture of the migration path of the wear debris under the coupling of the dust collection airflow.

[0120] (2) Considering the interaction between grinding debris and airflow, dynamic adjustment of flow field characteristics is achieved

[0121] The present invention uses computational fluid dynamics to simulate the flow characteristics of dust collection airflow under complex flow field structures, and can accurately characterize the velocity field, pressure field and turbulence changes inside and outside the dust collection device. Based on the discrete element calculation results, the position information and volume fraction of the wear debris particles are updated in real time to achieve dynamic adjustment of the flow field geometry, thereby accurately capturing the changes in flow field characteristics under the coupling of wear debris movement and airflow.

[0122] (3) Save on-site test resources and have a wide range of applications

[0123] The coupled simulation method provided by the present invention can accurately simulate the airflow and chip movement characteristics inside and outside the dust collection device of the grinding vehicle under different dust collection and grinding parameters. This method can truly restore the actual working conditions of the grinding vehicle, reduce dependence on field tests, save a lot of test resources, and provide reliable data for equipment design optimization. In addition, the simulation technology has a wide range of applications, not only limited to rail grinding vehicles, but can also be expanded to the research and development and improvement of other large-scale road maintenance machinery such as tunnel cleaning vehicles and roadbed suction vehicles, effectively improving their dust collection and cleaning performance.

[0124] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0125] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present invention or certain parts of the embodiments.

[0126] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0127] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for simulating the interaction between the dust collecting airflow and the grinding debris of a rail grinding vehicle, characterized in that: include: S1 constructs the internal and external flow field model of the grinding dust collection device by computational fluid dynamics method; S2 uses the discrete element method to construct a discrete particle model that can reflect the morphological characteristics of wear debris, and defines the criteria for the deposition of wear debris on the interior of the vehicle body and the wall surface such as the track plate; S3 is based on the bidirectional coupling method of discrete element and computational fluid dynamics. It simulates the interaction between the dust collection airflow and the grinding chips by exchanging and updating data between the internal and external flow field models of the grinding dust collection device and the discrete particle model.

2. The method according to claim 1, characterized in that: Step S1 includes: S11 treats the fluid as a continuous phase and describes the flow characteristics of the fluid through the Navier-Stokes equations in the Euler coordinate system. Solve; where ρ is the airflow density; t is the flow time; u is the airflow velocity in the absolute coordinate system; i is the tensor symbol; μ is the airflow viscosity; δ ij is the Kronecker function, which is 1 when i=j and 0 otherwise; S12 is based on the calculation results of sub-step S11, and by assuming that the air in the flow field is an incompressible fluid, defining the track plate and the body structure as wall boundary conditions, defining the dust collection suction port as the velocity outlet, and defining the outer edge boundary surface of the calculation domain as a pressure inlet with a standard atmospheric pressure, the flow field and the geometric body are divided into unstructured grids using meshing software, and the grid is encrypted in the slits between the grinding motors and between the track plate and the body fire curtain. The grid grinding chips with the highest computational efficiency are selected through the grid independence test to construct the internal and external flow field model of the grinding dust collection device.

3. The method according to claim 2, characterized in that Step S2 includes: S21 uses discrete element method to flexibly model the strip, blade, flake and spherical grinding chips produced by rail end face grinding; S22 is calculated by the force balance of particles in the Lagrangian coordinate system. Calculate the motion parameters of the wear debris in the dust collecting flow field; where m p is the particle mass, is the air velocity at the particle location, is the particle velocity, ρ p is the particle mass, For additional force, represents the fluid drag, τ r The relaxation time of the wear debris is calculated by the following formula (4): In formula (4), μ is the molecular viscosity of the fluid, d p is the diameter of the wear particle, drag coefficient α1, α2 and α3 are constants, Re is the Reynolds number, and the formula Calculate and obtain; S23 pass-through Calculate the Saffman lift force on the migration and diffusion of wear debris particles; where N = 2.594, d ij is the deformation tensor; S24 pass-through Calculate the critical deposition velocity; where R is the kinetic energy recovery coefficient of the collision, K is the effective stiffness of the collision, and the formula In formula (8), k w and k p Pass-through and Calculated; In formulas (9) and (10), E w and E p are the Young's modulus of the collision wall and the wear debris, v w and v p is the Poisson's ratio of the wall and the wear debris; S25 passes through the relationship between the wear debris impact velocity and the critical deposition velocity Define the criteria for the deposition of wear debris inside the vehicle body and on the wall surfaces such as track plates.

4. The method according to claim 3, characterized in that Step S3 includes: S31 solves the velocity field, pressure field and turbulence characteristics of the fluid by polishing the internal and external flow field models of the dust collector and according to the set initial conditions; S32 injects wear debris particles through a discrete particle model, solves the particle velocity and position information of a certain time step, and then transmits the particle velocity and position information of the time step to the CFD model; S33 calculates the volume fraction of the grid and the force of the flow field on the wear debris in a certain time step by polishing the flow field model inside and outside the dust collecting device and according to the flow field and particle information, and obtains the momentum exchange amount between the discrete phase wear debris particles and the continuous phase dust collecting airflow, and then updates the flow field information according to the momentum exchange amount; S34 The CFD model transmits the calculation data of sub-step S33 to the discrete particle model, so that the discrete particle model performs the incidence, contact and deposition calculations of the wear debris in the next time step based on the received calculation data and updates the position information of the wear debris; The steps S31 to S34 are repeatedly performed multiple times to simulate the interaction between the dust collecting airflow and the grinding debris.

5. A simulation system for the interaction between the dust collecting airflow and the grinding debris of a rail grinding vehicle, characterized in that: include: Modeling and analysis modules for: The internal and external flow field model of the grinding dust collection device was constructed by computational fluid dynamics method; A discrete particle model that can reflect the morphological characteristics of wear debris is constructed by discrete element method, and the criteria for determining the deposition of wear debris on the interior of the vehicle body and the wall surface of the track plate are defined; Based on the bidirectional coupling method of discrete element and computational fluid dynamics, the interaction between the dust collecting airflow and the grinding debris is simulated by transferring data between the internal and external flow field models of the grinding dust collecting device and the discrete particle model. The visualization output module is used to visualize the interaction between the simulated dust collection airflow and the wear debris.

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