Motion Characteristics Of Particles Research Articles

Motion of fine particles in a temperature gradient: Experiment, visualization, and numerical simulation studies

The migration and deposition processes of fine particles under the influence of temperature gradients and fluid flow are widely prevalent. Investigating the mechanisms of particle interactions in these processes contributes to the development of efficient dust removal techniques. In this work, experimental and numerical studies of particle motion in temperature gradient fields are conducted. The research encompasses both qualitative and quantitative analyses of particle motion influenced by thermophoresis and particle diameter. Qualitative analysis reveals that the motion characteristics of particles are jointly determined by gravity, drag force, and thermophoretic force, and the diameter range that exhibiting a notable influence of the thermophoretic force is 20–30 μm. Quantitative analysis shows that the manifestations of deposition and diffusion become more evident with an increasing temperature gradient. For instance, in comparison to the working condition with ΔT = 0 K and dp = 20 μm, the deposition mass increases by approximately 23% when ΔT = -15 K; conversely, it diminishes by about 11% when ΔT = 15 K. Additionally, the Discrete Phase Model (DPM) is employed to simulate the motion of gas-solid flow. This study presents a novel visualization system to observe particle motion in gas-solid systems to elucidate the mechanisms underlying the thermophoretic effect and establish a robust theoretical foundation for thermophoretic dust removal technology.

Motion characteristics and wear analysis of particles in the clearances of a twin-screw pump

The rotors of twin-screw pumps would be worn by hard particles for deep-sea oil and gas mixture transport. It led to the destruction of the seal clearance and the deterioration of pump performance. Based on the Euler–Lagrange method and dynamic grid technology, the transient numerical simulation of solid–liquid two-phase flow in a twin-screw pump was carried out and validated by experiment. The motion characteristics of particles in the tip, interlobe, flank clearance, and the causes of rotor wear were clarified. The results revealed that the severe wear at rotor tips was caused by the particles when they enter the tip clearance rather than leaving the tip clearance with the leakage jet flow. Particles passing through the flank clearance had high velocity and contributed to the wear at rotor tips. The main flow in the tooth chamber was disturbed by the interlobe and flank clearance leakage, even resulting in local high-speed reflux near the engagement. With the increase in the particle concentration and diameter, the collision frequency between particles and rotor tips increased, aggravating the risk of wear at rotor tips. The research could reveal the motion nature of particles following the liquid phase and their wear mechanism in twin-screw pumps.

Flow field analysis and particle erosion of tunnel‐slope systems under coupling between runoff and fast (slow) seepage

AbstractThe presence of particles on the surface of a tunnel slope renders it susceptible to erosion by water flow, which is a major cause of soil and water loss. In this study, a nonlinear mathematical model and a mechanical equilibrium model are developed to investigate the distribution of flow fields and particle motion characteristics of tunnel slopes, respectively. The mathematical model of flow fields comprises three parts: a runoff region, a highly permeable soil layer, and a weakly permeable soil layer. The Navier‒Stokes equation controls fluid motion in the runoff region, while the Brinkman‐extended Darcy equation governs fast and slow seepage in the highly and weakly permeable soil layers, respectively. Analytical solutions are derived for the velocity profile and shear stress expression of the model flow field under the boundary condition of continuous transition of velocity and stress at the fluid‒solid interface. The shear stress distribution shows that the shear stress at the tunnel‐slope surface is the largest, followed by the shear stress of the soil interface, indicating that particles in these two locations are most vulnerable to erosion. A mechanical equilibrium model of sliding and rolling of single particles is established at the fluid‒solid interface, and the safety factor of particle motion (sliding and rolling) is derived. Sensitivity analysis shows that by increasing the runoff depth, slope angle, and soil permeability, the erosion of soil particles will be aggravated on the tunnel‐slope surface, but by increasing the particle diameter, particle‐specific gravity, and particle stacking angle, the erosion resistance ability of the tunnel‐slope surface particles will be enhanced. This study can serve as a reference for the analysis of surface soil and water loss in tunnel‐slope systems.

The Study of Structural Optimization on Hydraulic Performance and Anti-Clogging Performance of Labyrinth Drip Irrigation Emitters

The core component of a properly functioning drip irrigation system is the drip irrigation emitter. Irrigation water containing impurities and sand particles can easily lead to clogging of the drip irrigation emitter, reducing the efficiency of the drip irrigation system. In this paper, orthogonal tests were used to optimize the flow channel structure, combined with the computational fluid dynamics–discrete element method (CFD-DEM) to analyze the flow index and sand particle motion characteristics. Clear water tests and short-cycle anticlogging tests were used to validate the results of the numerical simulation, and the relationship between the hydraulic performance and anti-clogging performance was revealed via linear regression. The results showed that the structural parameters of drip irrigation emitters were important factors affecting the flow index and sand movement characteristics. The order from largest to smallest was the turning angle, amount of interdental reference, flow channel depth, flow channel width, and width of the top base. The sand passage rate and the percentage decrease in velocity can be used as important indicators of anti-clogging performance, and there was a negative correlation between the two indicators. The flow channel with a 65° turning angle had the lowest flow index, and the sand passage rate can reach up to 91.48%; the reason was that the main flow region velocity was higher, the vortex region and the sand energy loss were small, which was not easy to clog. The equation for the relationship between flow index and sand passage rate was a negative correlation for drip irrigation emitters between a 65° and 75° turning angle. The drip irrigation emitter with a 65° turning angle had better hydraulic performance and anti-clogging performance.

Research on a new-designed Venturi ejector and dazomet particle motion characteristics for dilute-phase pneumatic conveying systems based on CFD-DEM

To disperse dazomet, a commonly used soil fumigant for soil disinfection, over large soil surfaces, dilute-phase pneumatic conveying can be utilized. Currently, most research has focused on pneumatic conveying systems for large particles, such as coal conveying or pneumatic seeding However, there has been almost no research on the dilute-phase pneumatic conveying of dazomet particles. Therefore, a coupled simulation model based on computational fluid dynamics and discrete element method (CFD-DEM) was established to study the effect of the structural parameters of the Venturi ejector on the motion of particles and airflow fields variation characteristics for the pneumatic conveying system of dazomet particles. Based on the Box–Behnken experimental design method, a 3-factor and 3-level response surface simulation experiment was carried out by selecting the contraction angle, throat diameter, and diffusion angle of the Venturi ejector as factors. The suction-flow ratio, average velocity of particles, average coordinates of particles in the vertical direction, and corresponding standard deviation at the outlet of the pipeline were chosen as response indexes. Multiple linear regression models were established between each factor and response index. The simulation results showed that the impact of factors on the 4 response indexes from strong to weak were throat diameter, contraction angle, and diffusion angle. With decreasing throat diameter, the suction flow ratio and average velocity of the particles increased. The average coordinates of the particles in the vertical direction decreased, while the standard deviation increased, indicating that the pneumatic conveying performance of the system increased. The optimal structural parameters for the contraction angle, throat diameter, and diffusion angle were 34.5°, 15 mm, and 12.0°, respectively. The experimental results demonstrated that the application precisions of the optimised Venturi ejector were 99.23%, 98.46%, and 98.56% at application rates of 15, 20, and 25 g/s, respectively. The results provide a theoretical reference for the structural optimisation of the Venturi ejector and operational performance evaluation of the pneumatic conveying system for dazomet particles.

Particle motion analysis and performance investigation of a fertilizer discharge device with helical staggered groove wheel

Enhancing the uniformity of fertilizer particles flow is crucial in fertilizer discharge device research, and the analysis of particle motion process contributes to improving fertilization performance. In this study, the discrete element method was employed to conduct a phenomenological analysis and numerical investigation of the particle motion characteristics influenced by structural feature parameters of the groove wheel-type fertilizer discharge device. A performance evaluation model based on the uniformity of fertilizer discharge and supplemented by the flow characteristics and mechanical properties of particles was established. The results demonstrated that the particles flow within the fertilizer bin exhibits a recirculating surge induced by the rotation of the groove wheel. The geometric morphology of the outer edge grooves and their spatial distribution along the groove wheel circumference affect the uniformity of fertilizer filling and discharge mass flow rate. The force exerted on the fertilizer particles and their potential breakage are primarily concentrated during the fertilizer compaction stage, while the particles flow forms a convergence due to the sliding of the fertilizer along the discharge slope. After optimization, the discharge CV is reduced from 91.54 % to 31.48 %, and the uniformity is improved by 60.06 %. This study proposes a helical staggered groove wheel fertilizer discharge device structural model, providing new insights for the optimization of agricultural fertilization machinery equipment.

Optical sorting by trajectory tracking with high sensitivity near the exceptional points

Exceptional points (EPs) in non-Hermitian systems embody abundant new physics and trigger various novel applications. In the optical force system, the motion of a particle near its equilibrium position is determined by the optical force stiffness matrix (OFSM), which is inherently non-Hermitian when the particle is illuminated by vortex beams. In this study, by exploiting the rapid variations in eigenvalues and the characteristics of particle motion near EPs of the OFSM, we propose a method to sort particles with subtle differences in their radii or refractive indices based on their trajectories in air. We demonstrate that the trajectory of a particle with parameters slightly larger than those corresponding to certain EPs closely resembles an ellipse. The increase in the major axis of the ellipse can be several orders of magnitude larger than the increase in particle radius. Furthermore, even a slight change in the refractive index can not only significantly alter the size of the ellipse but also rotate its orientation angle. Hence, particles with subtle differences can be distinguished by observing the significant disparities in their trajectories. This approach holds promise as a technique for the precise separation of micro and nanoscale particles.

Dynamic behavior of skyrmion collision: spiral and breath

A magnetic skyrmion is a particle-like topological soliton, which is an ideal candidate for developing high-density storage and logic devices due to its nonvolatility and tunability. In view of the particle motion characteristics of skyrmion, different skyrmions in a material inevitably interact in the form of short-range repulsion and long-range attraction. In this work, the dynamic characteristics of skyrmion collision in a ferromagnetic Co thin film are investigated by using micromagnetic simulations. It is found that the dynamic behavior of skyrmion after collision is highly dependent on the size of the strip, the initial velocity of skyrmion and magnetic damping constant. For the collision of two skyrmions, when the strip width exceeds the critical value, the skyrmions form a pair and rotate counterclockwise in the form of spiral and breath. It is interesting that the rotation and breath of skyrmions keep the same periodicity under the negligible damping, and the frequency increases with the increase of the initial velocity of skyrmion. Further, the collision of a system of three skyrmions reveals that they interact in pairs to form closed periodic trajectories. The results of the present work not only give an insight into the multi-skyrmion dynamics, but also provide guidance for the development of spintronic devices based on multi-skyrmion motion.

Investigating real-time monitoring indices of compaction quality from particle movement characteristics of distinctly-graded unbound aggregate materials subjected to vibratory compaction

The compaction quality greatly affects the in-service performance of unbound aggregate materials (UAMs); however, there still lack real-time, non-destructive, and effective indices for compaction quality assessment. This paper aimed to reveal meso-scale mechanisms of macroscopic vibratory compaction behavior and evaluate compaction quality from particle movement characteristics. A series of newly-developed laboratory vibratory plate compaction tests were conducted on UAM specimens of different gradations. The innovative self-powered, wireless sensors resembling realistic particles (termed as “SR sensors”) were placed inside UAM specimens to monitor three-dimensional (3D) particle accelerations and Euler angles during vibratory compaction. The effects of gradation and vibratory frequency on both macroscopic compaction behavior and meso-scale particle motion characteristics were analyzed. The results show that the entire vibratory compaction process can be divided into three distinct stages according to discernibly-staged particle movement patterns. The degree of compaction (DOC) of UAMs is significantly correlated with two novel particle-motion-based compaction quality indicators.

Study on nanometer cutting mechanism of single crystal silicon at different temperatures

Thermal-assisted single point diamond turning technology is currently one of the most important methods for realizing nano-scale machining. However, the nano-chip formation mechanism as the core of the nano-cutting mechanism is still unclear, which limits the development of this advanced technology. In this study, based on the molecular dynamics simulations, the nano cutting behaviour of single crystal silicon at different temperatures were studied. The cutting force, crystal structure, particle motion characteristics, stress-strain distribution and temperature distribution during chip formation process were systematically analyzed. The underlying mechanism of nano-chip formation in single crystal silicon was summarized. The results showed that the chip formation mechanism can be divided into two types: crack and shear. At low temperatures, chips are formed by crack propagation. The concentrated distribution of high stress triaxiality and local high temperatures at the crack tip are the main causes of crack propagation. With an increase in temperature, the chip formation mode gradually changed from crack to shear. The highly resolved shear stress distributed along the slip plane is the main reason for the expansion of the amorphous bands. In addition, it's found that higher quality machined surfaces can be obtained through chip formation process by shear than by crack.

Study on material distribution and equal-thickness formation mechanism of variable trajectory combined equal-thickness screen

ABSTRACT Equal-thickness screens are widely used in coal processing due to their advantages in overcoming the problems of material accumulation, low utilization of the screen surface, and poor screening accuracy. In this paper, the variable amplitude equal-thickness method was introduced into the combined screen, a novel variable trajectory combined equal-thickness screen was proposed and the combined excitation coefficient was introduced. The motion of the variable trajectory combined equal-thickness screen under different combined excitation coefficients was investigated using vibration test analysis system and the particle motion characteristics and the spatial distributions of materials in the screening process were analyzed using a high-speed camera system. The distribution law of the material was studied by screening experiment. The results show that when the combined excitation coefficient D is increased, the first section screen amplitude increases, the material transport speed of the first section increases, the material accumulation situation of the first section is resolved. When the unbalanced excitation coefficient k is increased, the material layer at the feeding end of each screen becomes thinner, the material transport speed of the first section screen is accelerated, the screen body does variable amplitude elliptical motion, the material is equal-thickness. When D = 1.2, k = 1.2, an optimum screening efficiency of 96.12% was obtained, with a total misplaced material content of only 1.82%.

Particle-Laden and Droplet-Laden Two-Phase Flows Past Bodies (a Review)

A review of computational–theoretical and experimental works devoted to the study of the flow of bodies by two-phase (dispersed) flows is carried out. The features of particle motion in the vicinity of bodies of various shapes, as well as the effect of the dispersed phase on resistance and heat transfer, are considered. Some consequences of the interaction of particles and droplets with the surface of streamlined bodies (erosive destruction, gas-dynamic spraying, icing, glowing) are analyzed.

Research on Wear Particle Online Monitoring Using Machine Vision for Rotating Machinery

A high-precision wear particle monitoring instrument based on numerical simulation, machine vision, multi-target tracking algorithm, and microfluidic technology is designed and developed in this paper. The instrument not only performs the traditional particle number and size detection, but also proposes a particle density detection model based on motion velocity. Firstly, an on-line visual microfluidic chip for oil particles motion was specially designed. Then a mathematical model relationship between particles velocity and particles diameter, particles density, oil viscosity, oil density was established by force analysis and solving the equation, which was used to explain the working principle of the instrument. Meanwhile, a multi-target tracking algorithm incorporating the characteristics of wear particles based on YOLOv5-Deepsort was custom-developed to detect the number, size, and motion characteristics of particles under the optical field of view of the image sensor. Secondly, the oil flow field distribution and the four factors affecting the particle motion characteristics in the self-developed chamber, particle size, particle material, particle radial position, and oil velocity were analyzed by using the finite element analysis in COMSOL. Finally, a pin-disk wear experimental validation results demonstrated this approach has excellent suitability to monitor the number, size, and density of wear particles with diameters above 20μm and densities above 2000 kg/m3 simultaneously. This portable oil particle monitoring instrument provides technical support for condition monitoring, fault diagnosis, and intelligent maintenance of rotating mechanical equipment.

Improving biomass mixture separation efficiency in multiple inclined channels of gas–solid fluidized bed: CFD-DEM simulation and orthogonal experiment

In order to improve the separation efficiency of clean biomass products and waste, a Z -shaped fluidized bed with multiple inclined channels is developed and applied in industrial production. Particle motion characteristics are studied using the computational fluid dynamics and discrete element method and verified by imaging experiments. The influences of operating parameters on the separation of mixture with different densities are investigated. A L 9 (3 4 ) orthogonal array is proposed to identify the main and secondary factors, and the optimal combination working condition is determined. Results demonstrate that the mixtures collide and separate many times in the inclined fluidization channels. The superficial velocity is the core for the separation efficiency, followed by the aspect ratio, and the conveying speed has a minimum effect. The Z -shaped fluidization system has an optimal performance when the superficial velocity is 6 m/s, the aspect ratio is 15/2.5 mm, the conveying speed is 2 m/s, and the mass flow rate is 0.156/0.033 kg/s. Compared with the average of the orthogonal table, the collection rate of clean products and impurities in the optimal combination increases by 70.4% and 10%, respectively. Moreover, particles are mainly perpendicular to the airflow with a zigzag movement pattern. The core-annulus structure and reflux of particles and gas are observed. The predictions on the biomass distribution agree well with experimental results, and the angle error is less than 14%. These findings will provide helpful guidance on biomass recovery utilization and other cleaner production. • A novel multiple inclined fluidization channel is designed for biomass separation. • Gas–solid coupling is studied by using the CFD-DEM. • A L 9 (3 4 ) orthogonal array is proposed to identify the main and secondary factors. • The collection rate of clean products in the optimal combination increases by 70.4%. • Biomass motion characteristics are verified by developed image processing technology.

Surface integrity and material removal mechanism in fluid jet polishing of optical glass

Fluid jet polishing (FJP) is a promising technology that has been increasingly used in the superfinishing of complex optical lenses, mirrors, and molds on several materials. The influence mechanism of polishing parameters on the damage characteristics, element composition, and surface quality of optical glass was studied through a series of FJP experiments to achieve the high-efficiency and low-damage ultra-precision polishing requirements of optical components. A numerical model for FJP was developed based on computational fluid dynamics (CFD), and the effects of slurry pressure and particle size on the flow field and particle motion characteristics were studied combined with statistical theory. The brittle-ductile transition model and erosion model when abrasive particles eroded optical glass were established to obtain a better understanding of the material removal mechanism during FJP. The damage control strategy can be clarified according to the coupling relationship between the impact velocity and particle size of abrasive particles when radial and transverse cracks are generated in the optical glass. The experimental results verify that the established model can predict the material removal characteristics well. The simulation results also indicate that the erosion removal of the optical glass by abrasive particles is a completely ductile mode under the polishing experimental conditions in this study. The results can provide solid theoretical support for equipment upgrade and process optimization of FJP.

Study on the Motion Characteristics of Particles Transported by a Horizontal Pipeline in Heterogeneous Flow

The worldwide problem of reservoir sedimentation has perplexed the water conservancy industry. The problem of reservoir sedimentation is particularly serious in sandy rivers in China and directly affects the normal function of reservoirs. Due to its effect on the economy and environmental protection, the self-priming pipeline dredging and sediment discharge technology has broad application prospects. Nevertheless, there are pressing problems in the transportation of slurry particles in the pipeline system of this new technology. The purpose of this study is to use physical model tests to analyze the influence of the sediment transport rate and pipeline velocity on the motion state of particles (aggregation transport, jump transport, and suspension transport) when a heterogeneous flow with different particle sizes is transported in the pipeline. The results indicate that under the same pipeline velocity and sediment transport rate, the thickness of the static particle accumulation layer decreases with the increase in particle size in the state of aggregation and transportation, and the smaller the particle size, the greater the particle movement speed in the case of aggregation and suspension transportation. During jump transportation, the velocity of particles above the critical inflection point Y’ increases with the decrease in particle size. The opposite is found below the critical inflection point Y’. At the same particle size and sediment transport rate, when the pipeline velocity increases, the particle transport transits from aggregation transport to jump transport and then to suspension transport. The larger the pipeline velocity, the greater the overall movement speed of particles. When gathering and conveying, if the pipeline flow rate increases by 1.5, the maximum movement speed of particles increases by 3.3. The curvature of the vertical velocity curve of the particles during jump transportation is not affected by the pipeline velocity. The particle velocity at the highest point increases with the increase in the pipeline velocity. During suspension transportation, the difference between the maximum and minimum vertical particle distribution velocities is exponentially related to the pipeline velocity. At the same pipe velocity and particle size, the overall particle velocity decreases with the increase in sediment transport rate.

Particle saltation trajectories in supercritical open channel flows: Roughness effect

AbstractBed load sediment transport governed by particle saltation in supercritical open channel flows causes bedrock incision in high‐gradient mountain streams and hydro‐abrasion at hydraulic structures. Hence, a better understanding of turbulent flow characteristics and particle dynamics is of prime importance for the prediction of river and landscape evolution, and for a sustainable design of hydraulic structures. To this end, we experimentally investigated single‐particle dynamics in supercritical open channel flows over fixed planar and abraded beds covering smooth, transitionally rough, and hydraulically rough regimes. The experiments were performed at the Laboratory of Hydraulics, Hydrology and Glaciology (VAW) of ETH Zürich in a wide range of hydraulic conditions with various channel width‐to‐depth aspect ratios (b/ho) and Froude numbers (F). We investigated the motions of five particle groups differing in shape, hardness, and diameter. By means of a high‐speed camera, the particle velocities and trajectory parameters—such as hop height and hop length—were determined using particle tracking velocimetry. The results reveal that at least 120 individual particles should be used in the tests to determine sound statistics of particle trajectories. In the present test conditions, the particles are dominantly transported in saltation. The effects of particle properties such as shape and diameter on the particle trajectories are negligible, while the rolling probability of the particles for a given flow condition increases with increasing diameter. Bed roughness was found to be the key parameter having a significant effect on the saltation trajectories and horizontal energy transfer. Hop height, hop length, and particle velocities, as well as horizontal energy transfer, increase with increasing bed roughness. Based on the saltation trajectory data, non‐dimensional equations are developed for each hydraulic regime and used to enhance the saltation–abrasion model of Sklar and Dietrich. The present findings contribute to a better understanding of particle motion characteristics under different hydraulic and roughness conditions, and their effect on the mechanics and prediction of bedrock incision and hydro‐abrasion in three‐dimensional supercritical open channel flows occurring in steeply sloped rivers and at hydraulic structures.

Research on wear characteristics induced by flowing microparticles in rotor cup

Wear at the inner surface of the rotor cup by granular impurities could adversely affect the slip of fibers and increase yarns’ hairiness. Therefore, understanding the mechanism of wear formation due to the moving granular impurities and the wear characteristics at the inner surface of the rotor cup is of great significance for the improvement of yarn quality. This paper numerically explores the mapping relationship between the motion characteristics of particles (i.e. spherical impurities) and the wear characteristics of the rotor cup via the combination of computational fluid dynamics (CFD) and the discrete element method (DEM). The simulation results are first validated against the experimentally obtained microscopic view of the surface of the discarded rotor cup. After that, the wear characteristics of the rotor cup under different rotating speeds and angles of the transfer channel are analyzed. The results show that the most serious cutting and impact wear is found at the rotor groove, followed by the first collision position of the slip surface. The cutting and impact wear in the rotor groove are positively correlated with the rotating speed, while are not affected by the angle of the transfer channel. The cutting and impact wear at the first collision position of the slip surface are negatively correlated with the rotating speed and the angle of the transfer channel. However, the impact and cutting wear at the first collision position is no longer affected significantly by the rotating speed when it is above 90000 rpm. Increasing the rotating speed and the angle of the transfer channel is found to reduce the second wear area on the slip surface of the rotor cup.

Investigation of particle flow characteristics in a CFB recirculation system using electrical capacitance volume tomography

Gas-solid fluidized beds have complex flow characteristics and opacity, and the particle motion characteristics in the recirculation system of circulating fluidized bed (CFB) have not been studied thoroughly. In order to study the motion of gas-solid two-phase flow in a CFB recirculation system, a 32-electrode electrical capacitance volume tomography (ECVT) system was developed with an imaging speed of 120 frames per second. Under various working conditions, the experimental platform of CFB was also built to measure the particle flow in the CFB recirculation system with the 32-electrode ECVT system, including the solid concentration and the flow velocity of particles in the branch pipe. When the velocity of fluidized gas U f is adjusted from 2.73 m/s to 1.76 m/s, the average solid concentration in the riser is roughly distribution of upper dilute and lower concentrated along the axial direction. With the decrease of U f , the average solid concentration generally showed an increasing trend, and the difference of solid concentration between different planes in the branch pipe gradually decreased. The slug length in the imaging area decreases, and the rising velocity of the slug in the riser above the branch pipe decreases. ECVT continuous images (U f = 2.73 m/s). • The 3-D solid concentration distribution in the CFB recirculation system was investigated. • ECVT continuous images under three different working conditions are given. • Solid concentration in the CFB recirculation system was acquired from the ECVT images. • Solid velocity was gained by analyzing the time lag of the neighbour planes.

Research on Forward Problem of Rail Detection Based on Magnetoacoustic Coupling.

According to the characteristics of rail defects, a rail microcrack detection method based on magnetoacoustic coupling effect is proposed in this paper. Firstly, the basic principle of a rail microcrack detection method based on magnetoacoustic coupling effect is described, and then the model is analyzed theoretically. Through simulation calculation, the current density distribution and Lorentz force distribution generated by electromagnetic excitation, the motion characteristics of particles under Lorentz force and the sound field distribution characteristics of magnetoacoustic signals generated by Lorentz force are obtained. Finally, an experimental platform was set up and the steel ring model was preliminarily tested. The magnetic and acoustic signals of the two steel ring boundaries excited by an electromagnetic field were collected. These signals correspond to the position distribution of the steel ring. The state change of rail microstructure will cause a change in the conductivity characteristics of rail materials, and will affect the characteristics and distribution of sound pressure in the detection. Therefore, the detection method based on the magnetoacoustic coupling effect can detect the surface microcracks of high-speed rail. This method has great feasibility and development potential in the field of rail flaw detection.