Numerical simulation research on gas migration with Y type ventilation

Gou, Yanan; Xue-zheng, Han

doi:10.1088/1755-1315/108/3/032054

Cited by 6 publications

(2 citation statements)

References 1 publication

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“…Jiong 22 conducted a simulation to examine the situation of air leakage when different “Y” type ventilation modes are in use and obtained the variation law of the “three zones” range of the goaf with the volume of air leakage. Gou 23 resolved the accumulated gas issue in the upper corner of the “Y” type by establishing the mathematical equation to control the law of gas migration. Ganbo 24 adopted a gas control scheme combining the features of long-distance, large-aperture, high-position fracture drainage, borehole drainage, and goaf blockage concerning the characteristics of the coal mine.…”

Section: Introductionmentioning

confidence: 99%

Research on controlling gas overrun in a working face based on gob-side entry retaining by utilizing ventilation type “Y”

Zhou

Jing

2023

Sci Rep

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To determine the characteristics of air leakage concerning a “Y” type ventilation in gob-side entry retaining with roof cutting, pressure relief, and the law of a resulted gas accumulation (GA), research is conducted by employing the CFD simulation incorporated with the gauged parameters of working face (WF) mining to analyze the air leakage of “Y” type ventilation. For this purpose, the 1201 fully mechanized coal mining face in the south Wu mining location of the Daxing coal mine is taken as an illustrative example to study the air leakage in the “Y” type ventilation. So, the gas concentration (GC) issue surpassing the limit in the upper corner of the goaf was simulated. The results show that the goaf is formed into an open space when roof cutting and pressure relief technology along the goaf is implemented. The air pressure at the upper corner of the WF would be the lowest, which is only 1.12 Pa. The airflow of air leakage under a pressure difference would move from the gob-side entry retaining to the goaf. Moreover, the simulation of mine ventilation indicates that the volume of air leakage positively correlates with the length of gob-side entry retaining. When the WF is advanced 500 m ahead, the maximum volume of air leakage would reach 247 m3/min within the range of 500–1300 m, and then the rate of air leakage gradually would decrease. When the WF is advanced at 1300 m, the air leakage would become the smallest, which is 175 m3/min. When gas control is under consideration, the effect of gas extraction would be best with the buried pipe whose depth and diameter are set to 4.0 m and 400 mm, respectively. So, the GC in the upper corner would become 0.37%. After the high-level borehole with a 120 mm diameter is mined, the GC in the deep goaf decreased to 3.52%, and the GC at the upper corner became further reduced to 0.21%. While the high-level borehole gas is extracted by employing the extraction system of the high-concentration gas, the extraction system of low-concentration gas is utilized to extract the upper corner gas of the WF, thus, the problem of gas overrun was resolved satisfactorily. During the recovery period of the mining, the GC at each gauging point was less than 0.8%, which effectively guided the secure production in the Daxing coal mine and provided a theoretical foundation to control gas overrun during the mining process.

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Section: Introductionmentioning

confidence: 99%

Research on controlling gas overrun in a working face based on gob-side entry retaining by utilizing ventilation type “Y”

Zhou

Jing

2023

Sci Rep

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“…In addition, CO 2 injection rate is an important parameter of fire prevention and extinguishing technology. Gou and Han 17 theoretically analyzed the gas migration in goaf, established the mathematical control equation of gas migration, and numerically simulated the effect of different technical means on gas control in goaf. Jiang and Zhang 18 established the three-dimensional flow-field mathematical model of the goaf, regarded the goaf as a uniform porous medium, carried out computer numerical simulation of the goaf, corrected the simulation results by using the experimental data, and achieved good simulation results.…”

Section: Introductionmentioning

confidence: 99%

Measurement and Numerical Simulation of Coal Spontaneous Combustion in Goaf under Y-type Ventilation Mode

et al. 2022

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In the process of advancing the working face, the temperature rise and oxidation characteristics of residual coal in goaf and the prediction of index gas are of great significance to mine fire prevention and safety production. Based on the coal spontaneous combustion test, the oxygen consumption and heat release characteristics of coal spontaneous combustion were analyzed by taking coal samples at the working face and carrying out temperature-programmed experiments in the laboratory. The characteristic temperature and index gas of coal spontaneous combustion were determined as the judgment bases of “three zones” of spontaneous combustion in goaf, and the influencing factors of coal spontaneous combustion in goaf under Y-type ventilation were analyzed. Based on the test results, the changes of gas composition in goaf during the advancing of the W1310 working face were monitored. According to the actual situation of the W1310 working face in the Gaohe energy mine of Lu’an group, the multifield three-dimensional numerical simulation calculation and analysis of gas composition in goaf were carried out, and the distribution of oxygen concentration field in goaf under different air volume ratios of machine roadway and air roadway was studied. Through the analysis of the parameters of porous media in the goaf, combined with the actual situation, the user-defined function was compiled for the key parameters such as porosity, viscous resistance coefficient, and inertial resistance coefficient of porous media in the goaf. The three-dimensional seepage field, gas concentration field, oxygen concentration field, and pressure field of the gas components in goaf during the advancement of the goaf working face were simulated. The comparison of the numerical simulation results with the field-measured results shows good agreement. In order to consider safety, the numerical simulation results with a wide oxidation temperature rise zone are used for linear regression, and the regression equation is used to dynamically determine the O 2 concentration at a point away from the goaf and to determine the “three-zone” state of the point, which is of great significance to guide the progress of the working face and safe production.

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A safe mining approach for deep outburst coal seam groups with hard‐thick sandstone roof: Stepwise risk control based on gas diversion and extraction

Liu

Lin

Xiao

et al. 2020

Energy Science & Engineering

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Protective seam mining is the preferred method for gas control and safe mining in high‐outburst coal seam groups. However, a hard‐thick sandstone roof (HTSR) triggers new gas problems when it covers directly above the first‐mined protective coal seam. To solve these problems, a typical case study in No. 12 Coal Mine was conducted. The simulation results indicate that the HTSR greatly prevents the plastic deformation of the upper roof formations without affecting the expansive deformation in the underlying protected seams. The pressure‐relief gas in protected seams will flow into the protective seam without continuing to migrate to roof strata, thereby turning the protective seam into a new high‐risk area. Therefore, roof presplitting (RPS) technology was proposed to effectively break the HTSR, create roof fracture passages, and divert the gob gas of the protective seam upward. Meanwhile, gob‐side entry construction (GSEC) was conducted to enhance gas discharge in the protective seam by adopting rapid filling, roof cutting, and active supporting technologies. Through the upper protective seam mining, RPS, and GSEC, gas migration passages were constructed step‐by‐step to divert the gas from high‐risk areas to low‐risk areas. As a key first step, gas diversion not only optimized the distribution of gas sources but also significantly reduced gas hazards. Source‐by‐source extraction was then performed to effectively control the high‐concentration gas in the newly formed gas source, further eliminating the mining risk. By applying the stepwise risk control method combined with gas diversion and extraction, the safe production was successfully achieved with excellent outburst prevention effects, and the gas extraction rate was significantly improved to more than 66%. This practice could be used for deep high‐gassy or high‐outburst coal seam group mining.

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Numerical simulation research on gas migration with Y type ventilation

Cited by 6 publications

References 1 publication

Research on controlling gas overrun in a working face based on gob-side entry retaining by utilizing ventilation type “Y”

Research on controlling gas overrun in a working face based on gob-side entry retaining by utilizing ventilation type “Y”

Measurement and Numerical Simulation of Coal Spontaneous Combustion in Goaf under Y-type Ventilation Mode

A safe mining approach for deep outburst coal seam groups with hard‐thick sandstone roof: Stepwise risk control based on gas diversion and extraction

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