Similar experimental study on diffusion and distribution of diesel exhaust in confined space of a coal mine.

In the confined space of the underground coal mine, which is dominated by transportation lanes, explosion-proof diesel-powered trackless rubber-wheeled vehicles are becoming the main transportation equipment, and the exhaust gas produced by them is hazardous to the health of workers and pollutes the underground environment. In this experiment, a similar test platform is built to study the effects of wind speed, vehicle speed, and different wind directions on the diffusion characteristics of exhaust gas. In this paper, CO and SO are mainly studied.

Experimental and numerical evaluation of the dust suppression efficiency of an innovative vortex pneumatic fog screen dust control device.

To effectively control the dust generated by coal mining operations, a new type of cyclonic pneumatic mist curtain dust control device was developed. Using CFD software, numerical simulations were conducted on the internal airflow velocity field, the exit velocity of the cyclonic pneumatic mist curtain, and the mist droplet particle field of the curtain. Experiments were carried out to measure the spray coverage, droplet size, and the dust control performance of the model device.

Flexible Thermoelectric Device Based on Protrusion-Structured Liquid Metal Elastomer for Gravity Heat Pipe.

Monitoring the temperature of the coal gangue mountains is fundamental to preventing their spontaneous combustion. However, the existing temperature monitoring systems fail to achieve stable, pollution-free temperature monitoring without affecting vegetation growth in these mountains. To address this issue, this work proposes a flexible thermoelectric device (FTD) based on a protrusion-structured liquid metal elastomer (LME).

Research on the mechanism of coal wall fragmentation and dust production characteristics in the perspective of differentiated discrete elements.

In order to efficiently and accurately control coal dust pollution in coal mining faces, this study addresses the insufficient research on the dust generation mechanism during cutting. Firstly, a similar experimental platform for simulating coal wall cutting with a drum cutter was used to investigate the changes in coal wall fragmentation and dust generation at drum speeds of 35 r/min, 50 r/min, 65 r/min, and 80 r/min. The experimental results revealed that the degree of coal wall fragmentation and dust generation increased with the increase in rotational speed, leading to a wider range of particle size distribution and an increase in the generation of fine dust particles.

Research on the Characteristics and Control Technology of Gas Disasters in the Gob of the Nonpillar Working Face Based on the DEM-CFD Coupled Model.

Gob-side entry retained by cutting roof (GERCR) is a novel and widely used nonpillar mining technology, but the gas emissions from gob are large, and the gas migration characteristics change obviously, which easily leads to serious safety accidents such as gas explosions and personnel suffocation. The discrete element method-computational fluid dynamics (DEM-CFD) coupled model was proposed and used to study the gas flow field in gob under this technology. Through the calculation of this coupled model, the gas distribution and emission characteristics of gob under different ventilation modes of GERCR technology were clarified, and the areas where the gas exceeds the limit in the roadway were determined.

Numerical simulation of the fine kinetics of dust reduction using high-speed aerosols.

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.

Study on the dust migration law and a spray dust suppression scheme in transportation roadway.

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.

Study on dust control technology of mobile spray combined with full-section fog curtain in return airway of header working face.

For the problem of coal dust pollution in the return air lane of the comprehensive mining working face of soft rock mines.Based on the principle of supersonic siphon pneumatic atomization dust control, mobile vehicle-mounted pneumatic spraying combined with full-section fog curtain dust control technology is proposed to address the coal dust pollution problem in the return air tunnel of the comprehensive mining working face of soft rock mines. This technology has a wider spraying range, stronger wind resistance and lower energy consumption.

Study on coal dust diffusion law and new pneumatic spiral spray dedusting technology at transfer point of mine cross roadway.

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.

Structural Model Construction and Optimal Characterization of High-Volatile Bituminous Coal Molecules.

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 nuclear magnetic resonance, X-ray photoelectron spectroscopy, and Fourier transform infrared. The molecular structure was determined.

Experimental and Molecular Dynamics Simulation Study for Preferring Coal Dust Wetting Agents.

To improve the efficiency of coal dust removal by water spray technology, the addition of wetting agents in water becomes the main dust removal method. The influence of sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate (SDDS), and sodium dodecylbenzene sulfonate (SDBS) on the wettability of coal dust is studied by experimental and molecular dynamics (MD) simulation. Measurement of the contact angle and surface tension was accomplished via relevant experiments for the three wetting agents, and their adhesion work, spreading work, and wetting work were also calculated.

Research on the mechanism of multilayer spiral fog screen dust removal at the comprehensive excavation face.

To solve the problem of the inability of traditional spray dust removal technology to efficiently restrain dust diffusion at the heading face, a multilayer spiral fog curtain dust control method based on spirally arranged pneumatic nozzles is proposed. In this paper, the k-ɛ turbulence model and K-H droplet breakage model are used. First, different airflow fields are analyzed by simulating the simultaneous injection of different numbers of nozzles, and the motion law of airflow interaction is obtained.

Correction to "Wetting Mechanism and Experimental Study of Synergistic Wetting of Bituminous Coal with SDS and APG1214".

[This corrects the article DOI: 10.1021/acsomega.1c05422.

Study on the characteristics of induced airflow and particle dispersion based on the multivariate two-factor model.

To examine the diffusion characteristics of airflow and dust particles, a multi-factor and multi-level physical self-developed testing system is established. In this study, bunker height, chute angle, feeding speed, coal granularity, and belt speed are selected as independent variables, and airflow velocity and dust concentration are the response variables. The two-factor interactive model is established to analyze the primary and secondary relationship between the independent variables and the response variables.

Wetting Mechanism and Experimental Study of Synergistic Wetting of Bituminous Coal with SDS and APG1214.

To solve the problem of poor dust wettability during coal mine dust treatment, sodium dodecyl sulfate (SDS) and alkyl glycoside (APG1214) were selected for compounding. An efficient, environmentally friendly, economical wetting agent was prepared. First, through molecular dynamics simulation studies, it was determined that the tail group C of SDS and APG1214 was adsorbed on the surface of bituminous coal, and the head groups S and O were adsorbed on the surface of water.

Reconstruction and seepage simulation of a coal pore-fracture network based on CT technology.

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.