Porosity model and air leakage flow field simulation of goaf based on DEM-CFD

Wang, Gang; Xu, Hao; Wu, Mengmeng; Wang, Yue; Wang, Rui; Zhang, Xiaoqiang

doi:10.1007/s12517-018-3499-1

Cited by 35 publications

(20 citation statements)

References 28 publications

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“…Coal industry serves an important role in the rapid growth of China's economy, and the increase in coal demand has brought an increase in the depth of mining. As a result, many disasters have occurred, causing a large number of casualties and property losses . Figure shows a statistical chart of the causes for different coal mine accidents (eg, blasting, gas, fire, floor, transportation, electromechanical, and other disasters) in China from 2007 to 2017.…”

Section: Introductionmentioning

confidence: 99%

Theoretical, numerical, and experimental analysis of effective extraction radius of coalbed methane boreholes by a gas seepage model based on defined criteria

Wang

Chang

et al. 2019

Energy Science & Engineering

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The effective extraction radius of borehole is the main parameter for determining the design and layout for coalbed methane extraction. This paper is aimed at the problem that the criteria and calculation methods for the effective extraction radius of coal seams are not comprehensive. With Wudong Coal Mine in China taken as an example, the critical gas pressure (0.441 MPa) for the calculation of effective extraction radius is first defined. Next, the gas seepage unit model around the borehole is developed, and the theoretical mathematical expression to calculate the effective extraction radius is derived. Then, the numerical simulation of gas extraction is carried out through a computational fluid dynamics program, and the effective extraction radius is obtained numerically. Furthermore, the influence of original gas pressure, borehole diameter, and negative pressure of gas extraction on gas extraction is analyzed. Finally, the results from the theoretical calculation and numerical simulation are validated by the field engineering measurement and the average relative error is small (less than 10%). The results indicate that the effective extraction radius has a linear relationship with the extraction time. Moreover, it is found that the original gas pressure is the main factor affecting the effective extraction radius and the effective extraction radius is proportional to the borehole diameter and negative pressure through analysis. Therefore, the above findings can provide a theoretical basis for determining parameters such as borehole spacing and extraction time of gas extraction in coal mines.

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Section: Introductionmentioning

confidence: 99%

Theoretical, numerical, and experimental analysis of effective extraction radius of coalbed methane boreholes by a gas seepage model based on defined criteria

Wang

Chang

et al. 2019

Energy Science & Engineering

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“…where D p is the average particle size ranging from 0.014 to 0.016 m [24] and n is the porosity of the porous medium.…”

Section: Numerical Simulation Of Large-diameter Drilling Extractionmentioning

confidence: 99%

Goaf Gas Control Improvement by Optimizing the Adjacent Roadway Large‐Diameter Boreholes

Wei

Yu³

2021

Advances in Civil Engineering

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This study introduced gas control technology in goaf using adjacent roadway large-diameter (550 mm) boreholes to control gas accumulation in the upper corner of a fully mechanized working face in high-gas coal seams. The gas control process in the upper corner and gas interception in goaf by large-diameter boreholes was analyzed using the CFD model of the gas flow in goaf. The latter considered the control equation of gas flow, the established permeability model of goaf, and the gas emission law in goaf. Using the 2-105 working face of the Tenghui Coal Mine, Shanxi Province, China, as a case study, the distribution patterns of gas concentration and flow field in the goaf for various extraction flow parameters and different positions of boreholes were numerically simulated. The dependences between various locations, drainage flows, and the gas concentration in the upper corner were determined and fitted by engineering equations. The evolution pattern of the spontaneous combustion zone in the goaf under the drainage conditions was also analyzed. The optimal borehole configuration parameters ensuring the extraction flow rate exceeding 3 m·s−1 and the effective gas control in the upper corner of the working face at a distance of 5 m–15 m behind the working face were identified. The engineering practice proved the feasibility of gas control in the goaf using the adjacent roadway large-diameter borehole. The gas concentrations in the return airflow and the upper corner of the working face were kept below 0.65 and 0.8%, respectively, to ensure production safety and improve the gas utilization efficiency.

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“…Zuo et al [80] used a self-built experimental platform to determine the effect of different air leakage conditions on the spontaneous combustion of residual coal and obtained an exponential relationship between air supply to the working face and the spontaneous combustion of broken coal in the gob. Wang et al [81] used the particle flow numerical simulation software PFC3D to simulate the collapse of the overlying rock layer in the void area, extracted the quantitative porosity data of the void area, imported it into FLUENT software, simulated the leakage flow field in the void area, and obtained the main leakage area of the working face. Lu and Qin [82] used numerical simulation to study the plastic deformation process of the coal column and deduced the distribution law of porosity of the coal column.…”

Section: Study On the Prevention And Control Of Fire And Explosion Risks In Gobsmentioning

confidence: 99%

Recapitulation and Prospect of Research on Flow Field in Coal Mine Gob

Zhang

Cheng

Wang

et al. 2021

Shock and Vibration

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Coal mine gob, mined-out areas in underground coal mines, often accumulates explosive methane-air mixtures that pose a deadly hazard to miners. A good understanding of the flow field in a sealed coal mine area is crucial in preventing and minimizing accidents associated with mine combustible gases and also for planning and implementing a mine rescue strategy. In recent years, the research on the flow field in the gob has changed from qualitative research in the past to quantitative research. This paper synthesizes the research results of flow field in gob in recent 40 years, covering the permeability of quarried areas, the airflow simulation in quarried areas, and the influence of ventilation parameters and geohydrological conditions on the flow field. Firstly, the overburden failure mechanism and fracture development characteristics of the mine gob, the distribution of porosity and permeability in the gob, and the relationship between them are introduced. Secondly, the development of research methods and numerical models used to study the flow field in mine gob is discussed. The distribution of the flow field in the gob under different conditions is expounded. Thirdly, the research on the prevention and control of fire and explosion risks in the gob is discussed. Finally, the problems to be solved in such research direction are addressed and suggestions are put forward.

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Porosity model and air leakage flow field simulation of goaf based on DEM-CFD

Cited by 35 publications

References 28 publications

Theoretical, numerical, and experimental analysis of effective extraction radius of coalbed methane boreholes by a gas seepage model based on defined criteria

Theoretical, numerical, and experimental analysis of effective extraction radius of coalbed methane boreholes by a gas seepage model based on defined criteria

Goaf Gas Control Improvement by Optimizing the Adjacent Roadway Large‐Diameter Boreholes

Recapitulation and Prospect of Research on Flow Field in Coal Mine Gob

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