In Situ Measurements and CFD Numerical Simulations of Thermal Environment in Blind Headings of Underground Mines

Wang, Wenhao; Zhang, Chengfa; Yang, Wenyu; Xu, Hong; Li, Sasa; Li, Chen; Ma, Hui; Qi, Guansheng

doi:10.3390/pr7050313

Cited by 19 publications

(18 citation statements)

References 22 publications

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“…The excavation equipment also influences the range of air backflow effects, which is confirmed by the results of other studies [29,30]. Therefore, it is essential to consider equipment in the roadway during numerical modelling, especially with such a complex The excavation equipment also influences the range of air backflow effects, which is confirmed by the results of other studies [29,30]. Therefore, it is essential to consider equipment in the roadway during numerical modelling, especially with such a complex ventilation as in overlap auxiliary ventilation systems.…”

Section: Resultssupporting

confidence: 85%

Study on Methane Distribution in the Face Zone of the Fully Mechanized Roadway with Overlap Auxiliary Ventilation System

2021

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An overlap auxiliary ventilation system is very often used for driving roadways in methane-rich coal seams. An overlap zone between the outlets of the forcing duct ends with a whirl flow air-duct (WFAD) and the exhaust duct ends with a dust scrubber that is created by applying the overlap system. This study examines the distribution of methane concentrations at various distances in the overlap zone. Maintaining a long overlap zone could increase the advance of the face. Therefore, the impact of overlap zone length on the methane concentration distribution, in and beyond the overlap zone, is investigated. The evaluation of methane concentrations is performed utilizing a well-established computational fluid dynamics (CFD) approach. The mathematical model of methane emissions into the roadway is adopted. Moreover, the CFD model is validated. A vortex of the return air, caused by the free airstream flowing out of the dust scrubber, is found. This air vortex is responsible for higher methane concentrations at the end of the overlap zone. Therefore, the conclusion can be drawn that maintaining the length of the overlap zone at 5 m to 10 m should be done to control permissible methane concentrations.

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Section: Resultssupporting

confidence: 85%

Study on Methane Distribution in the Face Zone of the Fully Mechanized Roadway with Overlap Auxiliary Ventilation System

2021

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“…The realizable k-epsilon model considers two equation models that deal with turbulent kinetic energy, k , and its rate of dissipation, ε , which are coupled with turbulent viscosity. This model is represented as follows [ 32 ]:

where G k represents the generation of turbulence kinetic energy due to the mean velocity gradients, m 2 /s 2 ; C 1 ε and C 2 ε are model constants; σ k and σ ε are the turbulent Prandtl numbers corresponding to the k equation and the ε equation, respectively; ρ is the density of the fluid, kg/m 3 ; µ t is the turbulent viscosity, represented by the following:

…”

Section: Numerical Analysismentioning

confidence: 99%

“…The geometric model grid after optimization is shown in Figure 3, and the statistics of the skewness and orthogonal quality are shown in Table 1. The maximal skewness was lower than 0.95 and the minimal orthogonal quality was higher than 0.1, suggesting that a high-quality grid had been generated [32]. The efficiency and accuracy of a numerical simulation process are closely related to grid quality, thus establishing grid independence is a necessary condition for analysis [33].…”

Section: Grid Generation and Independence Testsmentioning

confidence: 99%

Study on the Optimization and Oxygen-Enrichment Effect of Ventilation Scheme in a Blind Heading of Plateau Mine

2022

IJERPH

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There are abundant mineral resources in plateau areas, but it is difficult to extract them safely because the problem of hypoxia in plateau mines seriously affects the life and health of workers. In order to address the problem of hypoxia in the blind heading of a plateau metal mine, a three-dimensional roadway model was established based on field data of the Pulang copper mine in Yunnan province, China. The computational fluid dynamics (CFD) method was used to explore the optimal type of oxygen supply duct outlet, and to reveal the oxygen diffusion law influencing different ventilation factors. Grey correlation analysis was used to study the correlation values of the ventilation factors on the oxygen-enrichment effect in blind headings, such as forcing duct position, exhausting duct position, and extraction pressure ratio. The results demonstrated that the oxygen-enrichment effect of a slit oxygen outlet was better than that of the traditional oxygen supply method. When the direction of the oxygen outlet hole was 30° and the height above the roadway floor was 1.95 m, the oxygen increase effect was better than other forms of oxygen supply duct outlets. Grey correlation analysis revealed that the major influencing factors of the oxygen-enrichment effect in the roadway of the plateau mine, were, in descending order, as follows: forcing duct position, extraction pressure ratio, and exhausting duct position. This study has a positive guiding significance for improving the respiration environment in blind headings of plateau mines.

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“…K-Epsilon model considers two equation model that deals with turbulent kinetic energy, k, and its rate of dissipation, ε, which is coupled with turbulent viscosity. This model is given as [ 30 ]:

where G k represents the generation of turbulence kinetic energy due to the mean velocity gradients, m 2 /s 2 ; C 1ε and C 2ε are model constants; σ k and σ ε are the turbulent Prandtl numbers corresponding to the k equation and the ε equation, respectively; ρ is the density of the fluid, kg/m 3 ; µ t is turbulent viscosity given by:

…”

Section: Modeling and Simulationmentioning

confidence: 99%

Study on the Oxygen Enrichment Effect of Individual Oxygen-Supply Device in a Tunnel of Plateau Mine

2020

IJERPH

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Complex characteristics of the plateau environment such as low oxygen content seriously restrict the exploitation of abundant mineral resources in plateau areas. To regulate the hypoxia environment and improve the comfort of workers engaged in intense physical labor like tunnel excavation operations in plateau mines, an individual oxygen-supply device for tunnel of plateau mine was proposed to create local oxygen enrichment in the area around the human nose. The Computational Fluid Dynamics (CFD) method was used to judge the application’s effect of the individual oxygen-supply device in plateau mine, revealing the oxygen diffusion law under the influence of different oxygen enrichment factors. The orthogonal design and range analysis were used to measure the degree of influence of major factors such as oxygen-supply velocity, oxygen-supply concentration, and tunnel airflow velocity. The results demonstrate that the oxygen mass fraction of the air inhaled by the human had a positive correlation exponential function, a positive correlation linear function, and a negative correlation exponential function, respectively, concerning oxygen-supply velocity, oxygen-supply concentration, and tunnel airflow velocity. The range analysis revealed that the major influencing factors of oxygen enrichment in the tunnel of the plateau mine were, in a descending sequence, as follows: oxygen-supply concentration, tunnel airflow velocity, and oxygen-supply velocity, and the corresponding ranges were 2.86, 2.63, and 1.83, respectively. The individual oxygen-supply device achieved the best oxygen enrichment effect when the oxygen-supply velocity was 5 m/s, the oxygen-supply concentration was 60%, and the tunnel airflow velocity was 0.2 m/s, which increased the oxygen mass fraction of air inhaled by the human to 30.42%. This study has a positive guiding significance for the improvement of the respiration environment in the tunnel of plateau mine.

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In Situ Measurements and CFD Numerical Simulations of Thermal Environment in Blind Headings of Underground Mines

Cited by 19 publications

References 22 publications

Study on Methane Distribution in the Face Zone of the Fully Mechanized Roadway with Overlap Auxiliary Ventilation System

Study on Methane Distribution in the Face Zone of the Fully Mechanized Roadway with Overlap Auxiliary Ventilation System

Study on the Optimization and Oxygen-Enrichment Effect of Ventilation Scheme in a Blind Heading of Plateau Mine

Study on the Oxygen Enrichment Effect of Individual Oxygen-Supply Device in a Tunnel of Plateau Mine

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