The excavation of coal mines generates substantial dust, posing environmental and health risks for underground coal mine workers. To address the dust issue, a novel Vortex Air Flow Negative Pressure Entrainment Dedusting Device was developed. Through numerical simulations and a comprehensive experiment, factors influencing dust removal efficiency, such as the number of air ducts, wind speed, and pressure duct layout angle, were analysed. The result showed that the number of air ducts had the most significant effect on the suppression efficiency, while the pressure duct layout angle had the least significant impact. Six ducts with 25 m/s air velocity and 30 degrees pressure duct angle were determined as the optimum operational parameters for dust removal. Field tests with the optimum setting were also conducted. The results demonstrated the best dust control performance compared to other settings, which resulted in a 90% reduction in coal dust concentrations. The developed device provides underground coal mines with an effective method to control coal dust efficiently during the excavation.

The dust hazard and management at the belt transfer point is one of the most important issues in achieving effi-cient,safe and clean production in coal mines.To address the problem of dust pollution at the transfer point and to reduce the dust hazard at the transfer point,a multi-radial cyclone suction dust removal technology is proposed for the belt trans-fer point based on the cyclone suction theory.The technology is based on a certain number of inlets and jet angles on the side wall of the vertical drop pipe,with the suction outlet set above the drop pipe.The principle of operation is that the in-coming air-flow from the side wall of the drop pipe changes direction when it meets the side wall and the inlet jets interact with each other to form an upward flowing cyclone in the drop pipe.A simulated 3D solid model and a test platform for multi-radial cyclone suction dust removal at the belt transfer point are built.A combination of numerical simulations and experimental tests is used to study the distribution of air-flow and dust transport in the transfer point.In the numerical sim-ulation and experimental tests,eight air inlets are provided on each of the four-side walls of the drop pipe at an angle of 10°to the horizontal,and four-air inlets are provided on the guide chute,with the air inlets oriented tangential to the circle of the particle release position on the lower belt.According to the cyclonic suction theory,the greater the inlet air velocity on the drop pipe,the greater the pressure difference between the boundary of the drop pipe and the center,and the better the effect on dust collection.The simulation results show that the best inlet air speed for the multi-radial cyclone suction technology is 8 m/s,where the dust of less than 50 μm and the dust of less than 30 μm from the impact of the coal with the lower belt can be collected during the drop.Comparing the dispersion of the coal before and after falling in the test,it is concluded that the proportion of particles smaller than 50 μm in the coal on the lower belt is reduced by 47.96%,and the proportion of particles smaller than 5 μm is reduced by 44.62%after the application of the dust removal technology.It re-duces the proportion of harmful particles in the coal.By measuring the dust concentration at the ends of the guide chute and at the inlet,the test determines that the best inlet air speed for the multi-radial cyclone suction dust removal techno-logy is 8 m/s.At this time,the dust concentrations at the left and right ends of the guide chute and at the inlet are the low-est,and the dust removal efficiency is 97.71%and 99.92%respectively,and the overall dust removal efficiency at the transfer point can reach more than 95%.The study proves that the multi-radial cyclone suction dust removal technology at the transfer point can solve the problem of dust pollution,improve the working environment.

To solve the problem of excessive dust concentration in the belt transportation roadway of the mine. Numerical simulations were used to study the dust migration in the belt transportation roadway under 1.5 m/s ventilation conditions. The simulation results show the process of dust ejection from the inflow chute to contamination of the whole belt transportation roadway, and the spatial distribution of dust velocity. A comprehensive dust reduction scheme of “central suppression and bilateral splitting” was designed according to the dust distribution, with simultaneous control of the infeed chute and the roadway. In practical application, pneumatic spraying greatly reduces the amount of dust in the guide chute. The misting screen has a significant effect on dust collection and segregation. The solution effectively controls the dust in the space of 20 m on both sides of the transfer point, and the dust removal efficiency reaches more than 90%.

A numerical model of single-particle fog-dust collision coupling in a high-speed airflow based on three-phase flow theory. The effect of the fog-to-dust particle size ratio, relative velocity between the fog and dust particles, collision angle and contact angle at the wetting humidity function of dust particles is investigated. Different particle size ratios are determined for achieving the optimal wetting humidity for the interaction of high-velocity aerosols with dust particles of different sizes, for differ, that is, kPM2.5 = 2:1, kPM10 = 3.5:1 and kPM20 = 1.5:1. The optimal humidity increases with the relative velocity U between the fog and dust particles in the high-speed airflow. The larger the collision angle is, the lower the wetting rate is.The smaller the contact angle between the solid and liquid is, the better droplet wetting on dust is. The fine kinetic mechanism of single-particle fog-dust collision-coupling in a high-speed airflow is elucidated in this study.

In order to solve the problem of coal dust pollution at the transfer point, a three-dimensional numerical model of wind flow-coal dust at the loading point of underground rubber run was established by computational fluid dynamics (CFD) discrete particle model and finite element method and k-ε turbulence model, and the coal dust diffusion pollution phenomenon caused by the coal flow transfer under the intersection of wind flow in the cross tunnel was studied. Based on the simulation results of wind flow velocity contour, pressure contour and isochronous flow vector distribution, the influence mechanism of wind flow and coal dust characteristics on the distribution of wind flow and coal dust diffusion in the roadway is analysed, and a dust control and reduction system and treatment scheme with new pneumatic screw spray technology as the core is proposed to suppress coal dust pollution at the reloading point. The results of the study show that the wind flow distribution is mainly influenced by the intersection of tape traction and cross-roadway wind flow, showing a complex multi-layer distribution along the roadway and in the normal direction; the diffusion of coal dust of different particle sizes is influenced by the roadway wind flow, and coal dust with particle sizes in the range of 10μm~20μm is more easily diffused, and the dust with particle sizes in the range of 20μm~45μm is mainly collected and suspended near the vortex wind flow at the cross-roadway. The coal dust in the range of 20 μm~45 μm is more likely to gather in the vortex; the treatment system effectively controls the coal dust inside the dust cover, and the spiral-shaped transported droplet particle group formed by the pneumatic spiral spray combines with it efficiently, which verifies the dust control and reduction effect of the pneumatic spiral spray system at the transfer point, and the dust removal efficiency reaches 89.35%~93.06%, which provides relevant theoretical support for the treatment of dust pollution at the coal transfer point in underground coal mines It provides the theoretical support and means to control dust pollution at underground coal transfer points.

Coal mining has gradually extended deep, and coal dust disasters occur frequently under the condition of deep mining, which makes prevention and control difficult. The dust removal mechanism and technology are still one of the difficulties and emphases in the basic research of scientific and efficient dust removal in deep mining. Taking the raw coal collected from the Baozigou 9# coal seam as the research object, coal samples were analyzed by elemental industrial analysis, FT-IR, 13 C-NMR and XPS photoelectron spectroscopy, and the lowest energy molecular configuration of the bituminous coal aggregation state was constructed by Materials Studio. Three different ionic surfactants were selected, and two reagents were selected for each ionic surfactant. A surfactant/aqueous solution/bituminous coal system with the same concentration was constructed. The influence of different ionic surfactants on coal wetting was analyzed from the adsorption interaction energy and the mean square displacement diffusion coefficient of water. The results show that aromatic compounds in bituminous coal mainly exist in the form of naphthalene, and hydroxyl or ether oxy, carbonyl and carboxyl groups are the main oxygen-containing functional groups, accounting for 56.90%, 23.94% and 19.16%, respectively. The molecular structural formula of bituminous coal was determined to be C 165 H 128 O 10 N 2 S. The results of the molecular dynamics simulation show that the surface of coal is wetted by surfactant molecules through adsorption, the adsorption energy between the surfactant and coal is negative, and the order of absolute value is L-1>Y-2>L-2>F-1>Y-1>F-2. When three surfactants with the highest adsorption energy are mixed in pairs, the absolute value between them is Y-2+L-1. The distribution range of water molecules in the L-1+Y-2 system is the best, with a distance of 31-83 Å and a diffusion coefficient of 2.428×10 -5 cm 2 /s. The combination of zwitterionic surfactant MES-30 and anionic surfactant SDBS greatly improved the wettability of coal, indicating that it has the strongest wettability modification ability on bituminous coal surfaces.

The structural characteristics of coal at the molecular level are important for its efficient use. Bituminous coal from the Baozigou Coal Mine is investigated, using elemental analysis, C-13 nuclear magnetic resonance, X-ray photoelectron spectroscopy, and Fourier transform infrared. The molecular structure was determined. The aromatic compounds of bituminous coal molecules are primarily two- and three-ring structures, and the aliphatic structures are primarily in the form of methyl, ethyl side chains, and naphthenic hydrocarbons. The ratio of aromatic bridge carbon to peripheral carbon in the molecular structure is 0.279. Oxygen atoms in the form of carbonyl, phenolic hydroxyl and C-O, and nitrogen atoms in pyrroles. Thus, the average structure model of bituminous coal macro-molecules was constructed; the molecular formula was C169H128O10N2S, and the molecular weight was 2378. The aromatic structural units in the macromolecular structure of coal include four naphthalenes, three anthracenes, two tetracenes, and heteroatoms in the form of three carbonyl groups, one phenolic hydroxyl group, one pyrrole, and one pyridine. The structure optimization and annealing kinetic simulation of a single macromolecular structure model were performed. Chemical bonds such as bridge bonds and aliphatic bonds were found to be twisted, and pi-pi interactions between the aromatic sheets in the molecule produced adjacent aromatic sheets. This arrangement tends to be approximately parallel, and the total energy decreases from 6713.401 to 2667.595 kJ/mol, among which the bond stretching energy and van der Waals energy dominate. We used 20 bituminous coal macromolecular models to construct aggregated structural models. After optimization by molecular dynamics simulation, the macromolecules were constrained by the surrounding molecules, and the sheet-like aromatic carbon structures that were originally approximately parallel were distorted. The macromolecular structure model of bituminous coal constructed in this study provides a theoretical model basis for the optimal surfactant.

In order to address the problem of dust pollution at the transfer point of the coal transportation system, this paper carries out a numerical simulation on the dust diffusion law of the coal transportation system. The simulation results show that the dust concentration at the three openings in the transshipment point is the highest, and the farther away from the transshipment point, the lower the dust concentration. Depending on the simulation results, a pneumatic spray dust reduction scheme can be proposed by performing a field experiment. Based on the controlling variable experiments and existing studies, the parameters of pneumatic spray can be stated in the following way: the flowing rate should be laid out at 0.7 l/min, with its air velocity being 25 m/s and the working pressure being 0.6 MPa. The entire spray scheme can be verified through the computer simulation process. Thus, it can be calculated and determined that the spray scheme should be installed with four nozzles at the anterior end of the lower belt guide trough, with one nozzle at the back end and two nozzles at the upper belt feeding point. Eventually, the scheme has to be validated by the field experiments. Thus, the consequences of the on-spot experiment and test show that the scheme we have suggested is in a position to reduce the dust concentration effectively in the entire area of the transshipment point, bringing about the dust reduction rate over 90%.

To effectively solve the problem of dust pollution caused by the parallel double-belt transportation of coal in a coal preparation plant, taking the Huangyuchuan coal preparation plant as an example, a numerical model of the air flow-dust distribution was established by means of simulation. The flow lines between the strips of tape and the tail of the tape machine will gather, and there will be backflow on the right side of the 3001 tape and left side of the 3002 tape. Under the action of wind current, most of the dust particles larger than 10 μm are distributed in the range of 0–5 m on both sides of the tape; dust particles smaller than 10 μm spread to the entire preparation workshop. Combined with field test verification, dust pollution is mainly concentrated at the guide trough, the feed inlet, the rear of the machine, and the joint of the belt corridor. Based on this, a targeted spray dust reduction treatment plan is proposed. By measuring the dust concentration before and after the treatment of dust-polluted areas, it is proven that the dust reduction efficiency of this plan can reach more than 90%.

为解决矿井胶带运输巷粉尘质量浓度超标问题,设计一种新型节能气动喷雾降尘方案.在3 m/s通风条件下,采用数值模拟方法研究胶带运输巷粉尘运移情况,模拟粉尘从导料槽喷出至污染整个胶带运输巷的过程和粉尘速度的空间分布;提出同时治理导料槽和胶带运输巷内的中心抑制、两侧隔断综合喷雾降尘方案;在导料槽两端布置安装6个新型节能气动雾化喷嘴,胶带运输巷布置4道由高效节能气动雾化喷嘴组成的雾幕.结果 表明:该方案可有效降低导料槽粉尘涌出量,并对胶带运输巷中的粉尘起到捕集和隔断扩散作用;可有效将粉尘控制在转载点两侧20 m空间范围内,除尘效率达94.1％.

The dust removal efficiency of the existing dust control technologies for coal yards involving multiple dust production spots is low and cannot satisfy the requirements stipulated by the existing standards. This paper proposes a new type of vortex blowing suction dust control technology. The principle of dust control was examined through numerical simulations. The dust control efficiency of the single suction and vortex blowing suction methods was compared experimentally. The results indicated that most of the dust particles were collected by the vortex, and they moved in a spiral from the bottom to the top. The highest vortex airflow performance corresponded to an optimal blowing ratio of 4.814. The experimental comparison indicated that the dust removal performance of the vortex blowing suction technique was better. Specifically, for the formal and latter techniques, dust removal efficiency was 93.25% and 41.19%, and dust escape rate was 6.31% and 46.60%, respectively.

The distribution of multiscale pores and fractures in coal and rock is an important basis for reflecting the capacity of fluid flow in coal seam seepage passages. Accurate extraction and qualitative and quantitative analysis of pore-fracture structures are helpful in revealing the flow characteristics of fluid in seepage channels. The relationship between pore and fracture connectivity can provide a scientific reference for optimizing coal seam water injection parameters. Therefore, to analyse the change in permeability caused by the variability in the coal pore-fracture network structure, a CT scanning technique was used to scan coal samples from the Leijia District, Fuxin. A total of 720 sets of original images were collected, a median filter was used to filter out the noise in the obtained images, and to form the basis of a model, the reconstruction and analysis of the three-dimensional pore-fracture morphology of coal samples were carried out. A pore-fracture network model of the coal body was extracted at different scales. Using the maximum sphere algorithm combined with the coordination number, the effect of different quantitative relationships between pore size and pore throat channel permeability was studied. Avizo software was used to simulate the flow path of fluid in the seepage channels. The change trend of the fluid velocity between different seepage channels was discussed. The results of the pore-fracture network models at different scales show that the pore-fracture structure is nonuniform and vertically connected, and the pores are connected at connecting points. The pore size distribution ranges from 104 μm to 9425 μm. The pore throat channel length distribution ranges from 4206 μm to 48073 μm. The size of the coordination number determines the connectivity and thus the porosity of the coal seam. The more connected pore channels there are, the larger the pore diameters and the stronger the percolation ability. During flow in the seepage channels of the coal, the velocity range is divided into a low-speed region, medium-speed region and high-speed region. The fluid seepage in the coal seam is driven by the following factors: pore connectivity > pore and pore throat dimensions > pore and pore throat structure distribution. Ultimately, the pore radius and pore connectivity directly affect the permeability of the coal seam.

为治理落煤过程中产生的粉尘问题,基于涡旋气流的生成机制及粉尘粒子在涡旋气流场中的运移特性,提出一种控制落煤过程中粉尘扩散的涡旋吹吸式除尘技术;以落煤塔落煤过程为例,利用数值模拟方法分析涡旋吹吸式除尘气流场的变化特征;搭建仿真试验模型,通过仿真试验研究设备最佳涡旋性能参数,对比分析涡旋吹吸式除尘与单一抽吸除尘的除尘性能.结果表明:落煤过程中形成涡旋气流,大部分粉尘粒子被涡旋集聚,呈螺旋状自下而上运动.最佳吹吸比为4.814时,涡旋气流性能最佳;涡旋吹吸除尘性能高于单一抽吸,单位时间集尘质量浓度分别为314.27、191.94 mg/m3,除尘效率分别为93.25％和41.19％,粉尘逃散率分别为6.31％和46.60％.

为解决输煤系统转载点处导料槽内粉尘向外逸散而造成巷道粉尘严重污染的问题,运用Fluent软件对整个输煤皮带转载区域粉尘污染进行数值模拟,模拟得出导料槽内粉尘向外逸散过程和粉尘质量浓度分布规律.依据模拟结果提出气动喷雾降尘方案并进行现场试验,通过计算机仿真技术对该喷雾方案效果及喷雾后粉尘扩散规律进行模拟.现场试验和模拟结果表明,此方案能有效降低转载点整个区域范围内的粉尘质量浓度,降尘率达90％以上.

为研究露天煤场不同粒径沉积煤尘的扬尘规律,根据风洞实验和相似模拟实验基本原则搭建煤尘起尘实验装置,对露天煤场不同条件下不同粒径组成的沉积煤尘的扬尘现象和规律进行研究.采用最小二乘法和高斯牛顿法对实验数据进行回归分析.实验结果表明:沉积煤尘的起尘量随粒径的增大呈现起尘量先增大后减小的规律,当煤尘粒径接近0.23 mm,煤尘的起尘量最大,实验30 min最大值为16.4 kg;煤尘粒径小于0.115 mm,煤尘的起尘量极小试验最小值为0.003kg.回归分析得出平均粒径在0～0.23 mm范围内的不同含水质量分数的圆锥形煤尘静置在不同风速条件下煤尘起尘量的数学关系式.保证粉尘的含水质量分数在6％以上,煤尘所处的环境风速小于4 m/s可以有效地降低煤尘的二次扬尘.

Velocity analysis is always one of key steps in seismic data processing. The paper firstly analyzes the seismic reflection features of salt gypsum rocks in the research region and finely depicts and interprets salt gypsum horizons in response to the difficult problem on imaging of “three-gypsum two-salt” formations with strong deformation in the Amu Darya Area. Secondly, the paper optimizes the overall background velocity in the three intervals such as overlying salt gypsum formation, salt gypsum rock formation and underlying salt gypsum rock formation. Finally, the paper subdivides different sizes of horizon control grids of salt gypsum rock intervals for tomographic iteration velocity optimization. This plays a good role in correction of imaging amplitude distortion caused by salt gypsum rocks with complex deformation features and has established a set of theories and processes suitable for imaging of complex salt gypsum rocks in the Amu Darya Area.

In this paper,a vehicle brake test experiment system is designed and explored,which is based on the rolling drum table.The system includes mechanical unit and data gather perform unit.It can measure the main parameters when vehicle brake and can calculate other parameters.Also an anti-lock braking system is explored,and experiment shows this brake test experiment system works well and provides a good method of vehicle brake experiment.