scholarly journals Numerical Study of the Respirable Coal Dust Removal Performance of a Vortex Ventilation System at an Excavation Face

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2449 ◽  
Author(s):  
Xiaofei Liu ◽  
Ping Chang ◽  
Enyuan Wang ◽  
Zhenguo Zhang ◽  
Shuai Yang
Keyword(s):  
Numerical Study ◽  
Coal Dust ◽  
Ventilation System ◽  
Dust Control ◽  
Dust Removal ◽  
Two Phase ◽  
Fluid Behavior ◽  
Comparison Results ◽  
High Concentrations ◽  
Ventilation Systems

Coal dust is one of the most serious issues in coal mines. The miners at an excavation face have a high potential for exposure to high concentrations of coal dust. The main method for removing coal dust is by ventilation. To better control the coal dust at the excavation face, it is important to understand the coal dust movement patterns and distribution characteristics. This paper used the computational fluid dynamics (CFD) approach to simulate coal dust movement under two different ventilation systems. The Eulerian-Lagrange method was used to study the gas‒solid two-phase fluid behavior. The coal dust concentration distributions under the two ventilation systems are presented and further compared. From the comparison results, it is found that a vortex ventilation system has better coal dust removal performance. This ventilation system is recommended for excavation for better coal dust control and miners’ health protection.

scholarly journals Exploration on molecular dynamics simulation methods of microscopic wetting process for coal dust

2021 ◽  
Author(s):  
Qi Zhang ◽  
Xinyi Chen ◽  
Hetang Wang ◽  
Chaohang Xu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Molecular System ◽  
Molecular Model ◽  
Coal Dust ◽  
Molecular Layer ◽  
Dust Control ◽  
Dust Removal ◽  
Dynamics Simulation ◽  
Wetting Process

AbstractWet dust removal is one of the main technical measures in coal dust control, and coal dust wetting is the key factor to determine the effect of wet dust removal. In order to explore the micro-wetting process of coal dust, this paper uses molecular dynamics simulation to study the micro-wetting process of coal dust in different simulation conditions. The molecular dynamics simulation was carried out under different ensemble, thermodynamic states as well as relaxation pretreatment methods, then the H2O molecular layer and coal dust molecular layer in each simulation were quantitatively analyzed by relative concentration. The research results show that a method for establishing molecular model of lignite is proposed and the 2D periodic surface structure is more reasonable. The surface system of coal-H2O molecule is established by NVT aeration method, where the simulation result is close to the actual coal dust wetting process. The simulation effect of medium and large coal dust-H2O molecular system is better than that of small coal dust-H2O molecular system. This study provides a new solution for changing the empirical method of molecular dynamics simulation of coal system wetting and oversimplification of coal system.

Wall-Attachment Fan Drum Enclosed Dust Removal Theory and Technology of Mechanized Working Face

2013 ◽  
Vol 807-809 ◽  
pp. 653-662
Author(s):  
Wei Min Cheng ◽  
Yun Wang ◽  
Gang Zhou ◽  
Hao Wang
Keyword(s):  
Ventilation System ◽  
Simple Algorithm ◽  
Field Application ◽  
Dust Removal ◽  
Distribution Law ◽  
Two Phase ◽  
Suppression Effect ◽  
Working Face ◽  
Dust Distribution ◽  
Removal System

FLUENT software and SIMPLE algorithm which was based on parity grid was used to carry out the numerical simulation of spraying dust gas-particle two-phase flow field of the mechanized working face with a single pressure pumping hybrid ventilation system. The dust distribution law of the mechanized working face was mastered and the main dust prevention area was determined to be the middle of the roadway and wall-attachment fan drum enclosed dust removal system of mechanized working face was also planned to be established according to the simulation result. It had been proved that fully-mechanized coal winning machine enclosed dust removal system had a large advantage in reducing dust by computer simulation and field application, the dust suppression effect was remarkable.

Numerical Simulation Research on Gas-Dust Flow Field of Forced-Exhausted Hybrid Ventilation in Whole Rock Mechanized Heading Face

2013 ◽  
Vol 336-338 ◽  
pp. 873-879 ◽  
Author(s):  
Gang Zhou ◽  
De Ming Wang ◽  
Wei Min Cheng ◽  
Sen Cao
Keyword(s):  
Fluid Model ◽  
Coal Dust ◽  
Engineering Application ◽  
Simple Algorithm ◽  
Dust Concentration ◽  
Dust Control ◽  
High Concentration ◽  
Two Phase ◽  
Collocated Grid ◽  
Two Fluid Model

Euler-Euler two-fluid model was used to construct control equations of gas-solid two-phase flow, based on SIMPLE algorithm of collocated grid and FLUENT software, the pressure distribution of air-flowing field and dust field diffusion in fully-mechanized excavation face with different air-draft volume were simulated. The results show that with the increase of exhausted dust ability, diffusion intensity of producing dust pollution in driving head constantly decreases. Compared to air-draft volume of 320m3/min, when it is 600m3/min, the average dust concentration at the driver and whole section positions respectively decrease 51.28% and 56.51%, and high-concentration dust diffusion distance of the other workers position section decrease from 13.6m to 8.5m. Engineering Application indicates that the measured dust concentration is basically anastomosed with simulation result. When air-draft volume of dedusting fan is 600m3/min and dust control system with air curtain formed by forced fan drum is used, the dedusting rates of total coal dust and respirable dust on spot are respectively 95.1% and 96.1%, which achieves a great dedusting effect.

scholarly journals Numerical Study of Blowing-Suction Ventilation Systems Performance

2021 ◽  
Vol 5 (1) ◽  
pp. 36-46
Author(s):  
Pourya Shadkami Ahvazi ◽  
Navid P.Khabazi ◽  
Amirhossein Khayyami nejad
Keyword(s):  
Numerical Study ◽  
Ventilation System ◽  
Dust Particles ◽  
Industrial Processes ◽  
Flow Ratio ◽  
Current Ratio ◽  
Mixing Parameter ◽  
Industrial Ventilation ◽  
Suction Flow ◽  
Ventilation Systems

In most industrial processes, toxic pollutants and vapors are produced and released, which cause various diseases in people working in industry and irreparable damage to the environment. Industrial ventilation systems are considered as one of the most effective methods of reducing and controlling gaseous pollutants and dust particles. One of the effective systems in industrial ventilation is blowing -suction ventilation systems. In this study, the effect of flow ratio (ratio of blowing flow to suction flow) and direction of blowing jet air on the performance of blowing-suction ventilation system was investigated numerically. The mixing parameter has been used as an indicator to measure the performance of the ventilation system. The results showed that the performance of the ventilation system blowing-sucking by reducing the current ratio improved exponentially. It was also found that one of the ways to improve the performance of the blowing – suction ventilation system is to reduce the direction of the blowing angle.

scholarly journals The Influence of Ventilation Arrangement on the Mechanism of Dust Distribution in Woxi Pithead

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Zhiyong Zhou ◽  
Pei Hu ◽  
Chongchong Qi ◽  
Tianpei Niu ◽  
Ming Li ◽  
...  
Keyword(s):  
Numerical Study ◽  
Numerical Models ◽  
Ventilation System ◽  
Three Dimensional ◽  
Sensitivity Study ◽  
Concentration Data ◽  
Two Phase ◽  
Air Volume ◽  
Working Face ◽  
Dust Distribution

Suppressing and removing mine dust from the working face is an important task for underground mines worldwide. In this paper, a numerical study was carried out to investigate the influence of ventilation arrangement on the mechanism of dust distribution. The Woxi Pithead of Hunan Chenzhou Mining Co., Ltd, China, was used as a case study, which adopted a widely used far-pressing-near-absorption (FPNA) ventilation system. Based on the theory of gas-solid two-phase flow, the program ANSYS Fluent was utilized, and the three-dimensional airflow migration and dust diffusion numerical models were simulated. The established computational fluid dynamics (CFD) models were validated using the airflow velocity data and the dust concentration data monitored at different positions from the operating coal mine. A comprehensive sensitivity study was conducted to investigate the influence of four parameters on dust suppression, including the distance of pressure air duct outlet from working face (Lp-outlet), the distance of exhaust air duct inlet from working face (Le-inlet), the ratio of pressing air volume to lab sorption air volume (K), and the installation height of the air duct (H). The optimum ventilation layout parameters were obtained through the simulation of the wind field and dust behaviour. The results show that there were four regions during the airflow field, namely, the jet zone, the recirculation zone, the vortex zone, and the mixing zone of pressure and exhaust airflow. All four parameters were found to have an important influence on the mass concentration of dust, and the optimum ventilation layout parameters were determined to be Lp-outlet = 18 m, Le-inlet = 3 m, K = 1.2, and H = 1.6 m.

scholarly journals Numerical Study on Infrared Optical Property of Diffuse Coal Particles in Mine Fully Mechanized Working Combined with CFD Method

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Wen-Zheng Wang ◽  
Yan-Ming Wang ◽  
Guo-Qing Shi ◽  
De-Ming Wang
Keyword(s):  
Infrared Radiation ◽  
Numerical Study ◽  
Coal Dust ◽  
Mie Scattering ◽  
Dust Particles ◽  
Dust Transport ◽  
Mine Dust ◽  
Comparison Results ◽  
Coal Particles ◽  
Cfd Method

Coal dust seriously threatens the safety and occupational health of coal mines. Numerical simulation research on the infrared radiation characteristics of diffused coal dust is carried out in fully mechanized working faces based on the optical monitoring problem of dust particles in mine atmospheric environments. The CFD method is applied to obtain the law of dust transport and distribution. Combined with Mie scattering model, the infrared radiation change characteristics and spectral selection of diffused coal dust particles are simulated and analyzed along the working face. The comparison results show the following: the attenuation and scattering characteristics of mine dust particles system are first enhanced, and then they weaken as the distance from dust source increases. The infrared attenuation of mine dust at the center of the vertical cross-section is generally greater than that at the roof and floor in the same location. The dispersion of mine dust directly determines the attenuation contribution of respirable dust to total dust. Moreover, the infrared absorption effect of functional groups in coal causes the infrared attenuation effect of coal dust to have obvious optical selectivity along the roadway, the existing optical “window.”

Numerical Simulation Investigation of Dust-Controlling Equipment of Main Fan Diffuser of Coal Mine

2011 ◽  
Vol 356-360 ◽  
pp. 1293-1297
Author(s):  
Shi Qiang Chen ◽  
Hai Qiao Wang ◽  
Jian Lin Cheng
Keyword(s):  
Coal Mine ◽  
Coal Dust ◽  
Dust Control ◽  
Physical Models ◽  
Phase Flow ◽  
Dust Pollution ◽  
Two Phase ◽  
Computational Fluid Dynamics Cfd ◽  
Gravity Sedimentation ◽  
Main Fan Diffuser

In order to decrease coal dust pollution of industry square, two types of dust-controlling equipment of main fan diffuser of coal mine are designed by virtue of inertia separation and gravity sedimentation. On the basis of field conditions, the physical models of two equipments are constructed. In application of Computational Fluid Dynamics (CFD), dynamic and kinetic fields of two-phase flow in two equipments are researched. The results show that the application of dust control equipment of main fan diffuser is available approach of decreasing coal dust pollution in industry square of coal mine.

scholarly journals Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3634
Author(s):  
Grzegorz Czerwiński ◽  
Jerzy Wołoszyn
Keyword(s):  
Mass Transfer ◽  
Phase Change ◽  
Heat Dissipation ◽  
Cooling System ◽  
Numerical Study ◽  
Relaxation Parameter ◽  
Phase Changes ◽  
Transfer Time ◽  
Two Phase ◽  
Time Relaxation

With the increasing trend toward the miniaturization of electronic devices, the issue of heat dissipation becomes essential. The use of phase changes in a two-phase closed thermosyphon (TPCT) enables a significant reduction in the heat generated even at high temperatures. In this paper, we propose a modification of the evaporation–condensation model implemented in ANSYS Fluent. The modification was to manipulate the value of the mass transfer time relaxation parameter for evaporation and condensation. The developed model in the form of a UDF script allowed the introduction of additional source equations, and the obtained solution is compared with the results available in the literature. The variable value of the mass transfer time relaxation parameter during condensation rc depending on the density of the liquid and vapour phase was taken into account in the calculations. However, compared to previous numerical studies, more accurate modelling of the phase change phenomenon of the medium in the thermosyphon was possible by adopting a mass transfer time relaxation parameter during evaporation re = 1. The assumption of ten-fold higher values resulted in overestimated temperature values in all sections of the thermosyphon. Hence, the coefficient re should be selected individually depending on the case under study. A too large value may cause difficulties in obtaining the convergence of solutions, which, in the case of numerical grids with many elements (especially three-dimensional), significantly increases the computation time.

scholarly journals Numerical Study on an Interface Compression Method for the Volume of Fluid Approach

Fluids ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 80
Author(s):  
Yuria Okagaki ◽  
Taisuke Yonomoto ◽  
Masahiro Ishigaki ◽  
Yoshiyasu Hirose
Keyword(s):  
Linear Theory ◽  
Volume Fraction ◽  
Numerical Study ◽  
Volume Of Fluid ◽  
Interfacial Wave ◽  
Validation Process ◽  
Two Phase ◽  
Numerical Diffusion ◽  
Mesh Resolution ◽  
Water Reactors

Many thermohydraulic issues about the safety of light water reactors are related to complicated two-phase flow phenomena. In these phenomena, computational fluid dynamics (CFD) analysis using the volume of fluid (VOF) method causes numerical diffusion generated by the first-order upwind scheme used in the convection term of the volume fraction equation. Thus, in this study, we focused on an interface compression (IC) method for such a VOF approach; this technique prevents numerical diffusion issues and maintains boundedness and conservation with negative diffusion. First, on a sufficiently high mesh resolution and without the IC method, the validation process was considered by comparing the amplitude growth of the interfacial wave between a two-dimensional gas sheet and a quiescent liquid using the linear theory. The disturbance growth rates were consistent with the linear theory, and the validation process was considered appropriate. Then, this validation process confirmed the effects of the IC method on numerical diffusion, and we derived the optimum value of the IC coefficient, which is the parameter that controls the numerical diffusion.

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