Remote characterization of ventilation systems using tracer gas and CFD in an underground mine

Xu, Guang; Jong, Edmund C.; Luxbacher, Kray; Ragab, Saad A.; Karmis, M.

doi:10.1016/j.ssci.2015.01.004

Cited by 44 publications

(18 citation statements)

References 10 publications

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“…A mesh independence study considers the effect of the number of model cells on the numerical solution, which is essential in CFD modeling. Mesh refinement can reduce the probability of solution divergence and ensure that the numerical results approach the exact solution of the governing equations [30]; however, unnecessarily increasing the number of model cells reduces solution efficiency, thereby wasting computational resources [31]. To minimize the impact of the mesh on the calculation accuracy and to select a suitable number of cells to ensure adequate convergence speed, a medium mesh, with about 2 million cells, and a fine mesh, with about 4 million cells, were built.…”

Section: Mesh Independence Studymentioning

confidence: 99%

Computational Fluid Dynamic Simulation of Inhaled Radon Dilution by Auxiliary Ventilation in a Stone-Coal Mine Laneway and Dosage Assessment of Miners

Zhou

Chang

2019

Processes

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Inhaled radon status in the laneways of some Chinese stone-coal mines is a cause of concern. In this study, computational fluid dynamics simulations were employed to investigate three flowrates of the dilution gas (2.5, 5, and 7.5 m 3 /s) and radon distributions at realistic breathing levels (1.6, 1.75, and 1.9 m). The results showed that there are obvious jet-flow, backflow, and vortex zones near the heading face, and a circulation flow at the rear of the laneway. A high radon concentration area was found to be caused by the mining machinery. As the ventilation rate increased, the radon concentrations dropped significantly. An airflow of 7.5 m 3 /s showed the best dilution performance: The maximum radon concentration decreased to 541.62 Bq/m 3 , which is within the safe range recommended by the International Commission on Radiological Protection. Annual effective doses for the three air flowrates were 8.61, 5.50, and 4.12 mSv.

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Section: Mesh Independence Studymentioning

confidence: 99%

Computational Fluid Dynamic Simulation of Inhaled Radon Dilution by Auxiliary Ventilation in a Stone-Coal Mine Laneway and Dosage Assessment of Miners

Zhou

Chang

2019

Processes

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“…Among the gas extraction test methods, the gas pressure method, gas content method, and gas tracer method are three common methods for measuring the effective extraction radius. The gas tracer method has low reliability, and thus, it cannot be used to analyze the degree of influence and obtain the effective extraction radius accurately .…”

Section: Introductionmentioning

confidence: 99%

“…Researchers have established mathematical models to describe the laws of gas flow in coal seams around boreholes and have used the CFD software for numerical simulation to obtain the effective extraction radius of boreholes along coal seams. 12,23,30,35,36 Among the gas extraction test methods, the gas pressure method, 26,30 gas content method, 37 and gas tracer method 38 are three common methods for measuring the effective extraction radius. The gas tracer method has low reliability, and thus, it cannot be used to analyze the degree of influence and obtain the effective extraction radius accurately.…”

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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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“…The solver was set to segregated and a standard two equation k-ε model was introduced to simulate tracer gas and airflow migration. To acquire a more accurate result, the second order upwind was adopted to calculate momentum, turbulent kinetic energy, turbulent dissipation rate and mass of SF 6 . The solver PRESTO!…”

Section: Basic Approach and Boundary Conditions Of Simulationmentioning

confidence: 99%

Numerical Simulation of Several Parameters of Distribution Uniformity of Tracer Gas in Stope

Cui¹,

Chang²

2017

TOEFJ

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Tracer gas technology is an effective way to evaluate underground coal mine ventilation system, especially in stope, air leakage from working face to gob can be quickly detected by this method. While tracer gas distribution characteristics may be different with the variation of ventilation parameters, therefore, ascertaining the uniform distributed location as sampling point is essential to improve the measuring accuracy of tracer gas technology. This study conducts simulations of tracer gas distribution in four ventilation models with different parameters, aiming to analyze the effects of gob and height difference between roadway and working face on tracer gas distribution uniformity. The result shows the porous characteristics of gob is not conductive to tracer gas uniform distribution, the height difference between roadway and working face increases the turbulence intensity of airflow and promotes the uniform distribution of tracer gas. In no height difference stope, tracer gas and airflow can be mixed uniformly at 5D of return roadway, but in height difference stope, only 1D is required. Finally, a practical case study is conducted to verify the validity of simulation.

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Remote characterization of ventilation systems using tracer gas and CFD in an underground mine

Cited by 44 publications

References 10 publications

Computational Fluid Dynamic Simulation of Inhaled Radon Dilution by Auxiliary Ventilation in a Stone-Coal Mine Laneway and Dosage Assessment of Miners

Computational Fluid Dynamic Simulation of Inhaled Radon Dilution by Auxiliary Ventilation in a Stone-Coal Mine Laneway and Dosage Assessment of Miners

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

Numerical Simulation of Several Parameters of Distribution Uniformity of Tracer Gas in Stope

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