Airflow disturbance induced by coal mine outburst shock waves: A case study of a gas outburst disaster in China

Zhou, Aitao; Zhang, Meng; Wang, Kai; Elsworth, Derek; Wang, Jiawen; Fan, Lingpeng

doi:10.1016/j.ijrmms.2020.104262

Cited by 36 publications

(14 citation statements)

References 21 publications

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“…The methane seam pressure determines the quantity of methane contained in the seam and affects the rate of methane release from the seam as a result of mining operations [14]. It has been found many times that the precise determination and control of methane pressure in coal seams are essential for the safety of underground work [3,9,[15][16][17]. Despite the fact that the mining regulations do not provide for the requirement to determine the methane seam pressure as often as for the obligatory measurement of methane content, there are countries, such as China, where the outburst risk assessment is based solely on the methane pressure in the seam [18].…”

Section: Introductionmentioning

confidence: 99%

MLP-Based Model for Estimation of Methane Seam Pressure

2021

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One of the principal indicators of the methane hazard in coal mines is gas pressure. This parameter directly affects the methane content in the seam as well as the rate of its release resulting from mining operations. Because of limitations in the existing methods for methane seam pressure measuring, primarily technical difficulties associated with direct measurement and the time-consuming nature of indirect measurement, this parameter is often disregarded in the coal and gas outburst forecasts. To overcome the above-mentioned difficulties, an attempt was made to estimate the methane seam pressure with the use of artificial neural networks. Two MLP-based models were developed to estimate the average and maximum methane seam pressure values, respectively. The analyses demonstrated high correlation between the values indicated by the neural models and the reference values determined on the basis of sorption isotherms. According to the adopted fit criterion, the prediction errors for the best fit were 2.59% and 3.04% for the average and maximum seam pressure values, respectively. The obtained determination coefficients (exceeding the value of 0.99) confirmed the very good predictive abilities of the models. These results imply a great potential for practical application of the proposed method.

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Section: Introductionmentioning

confidence: 99%

MLP-Based Model for Estimation of Methane Seam Pressure

2021

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“…e greater the air speed is or the smaller the roadway angle is, the smaller the possibility of gas accumulation is; the transient model of airflow stability induced by gas accumulation was established, and it was found that the main reason for airflow disorder is the air pressure of gas accumulation [13]. Furthermore, methane buoyancy [14], shock wave, and main fan pressure [15] could cause the flow to stall or reverse. e dynamic simulation of gas migration in coal and gas outburst can be realized with the help of the mine ventilation network software during the disaster period [16].…”

Section: Introductionmentioning

confidence: 99%

The Airflow Reversal Law in Ventilation System after Coal and Gas Outburst in Tunneling Roadway

Wang

Cheng

et al. 2021

Shock and Vibration

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Considering the coal and gas outburst phenomenon in the mining space, this paper analyzes the main characteristics of coal and gas outburst accidents, defines the outburst airflow reversal degree, and constructs a simplified topology graph of tunneling ventilation system, while the air door is not destroyed. Using the numerical simulation method, this paper elaborates on the relationship between the outburst pressure and airflow reversal degree. The results indicate that the inlet pressure increases to 264 hPa and the outlet pressure increases to 289 hPa when the outburst pressure increases from 1 hPa to 1 MPa, and the relative variation coefficient of pressure decreases from 1501.5 to 1.62 in the inlet of return airway and decreases from 2002 to 1.65 in the outlet of return airway. Furthermore, the air velocity decreases from −1.38 to −284.44 m/s in the inlet and increases from 3.10 to 297.38 m/s in the outlet. Moreover, the gas concentration of the inlet and outlet in return airway increases rapidly with the increase of outburst pressure. When the outburst pressure is greater than 0.15 MPa, the gas concentration will be over 98% in tunneling ventilation system. This paper also finds out a cubic polynomial relationship existing between the reversal degree and the outburst pressure. It provides the prediction of coal and gas outburst and serves as a guidance in case mine ventilation disturbances occur.

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“…In practical engineering applications, porous barriers have significant potential in mitigating the damage caused by shock waves [1][2][3][4][5]. The shock-induced damage or influence happens in many situations such as the influence of explosion waves on the stability of corridor structures in mine tunnels or oil wells [6,7], the damage of shock waves in a high-speed train tunnel to ancillary facilities [8,9], the sonic boom problem caused by supersonic aircraft breaking through the sound barrier [10,11], etc. Therefore, it is of great significance to study the propagation behavior of a shock wave when it passes through a perforated-plate array and reveal the mechanisms that lead to the change in the shock wave intensity.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Air Flow Induced by Shock Impact on an Array of Perforated Plates

Zhang

Feng

Sun

et al. 2021

Entropy

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This study is focused on the propagation behavior and attenuation characteristics of a planar incident shock wave when propagating through an array of perforated plates. Based on a density-based coupled explicit algorithm, combined with a third-order MUSCL scheme and the Roe averaged flux difference splitting method, the Navier–Stokes equations and the realizable k-ε turbulence model equations describing the air flow are numerically solved. The evolution of the dynamic wave and ring vortex systems is effectively captured and analyzed. The influence of incident shock Mach number, perforated-plate porosity, and plate number on the propagation and attenuation of the shock wave was studied by using pressure- and entropy-based attenuation rates. The results indicate that the reflection, diffraction, transmission, and interference behaviors of the leading shock wave and the superimposed effects due to the trailing secondary shock wave are the main reasons that cause the intensity of the leading shock wave to experience a complex process consisting of attenuation, local enhancement, attenuation, enhancement, and attenuation. The reflected shock interactions with transmitted shock induced ring vortices and jets lead to the deformation and local intensification of the shock wave. The formation of nearly steady jets following the array of perforated plates is attributed to the generation of an oscillation chamber for the inside dynamic wave system between two perforated plates. The vorticity diffusion, merging and splitting of vortex cores dissipate the wave energy. Furthermore, the leading transmitted shock wave attenuates more significantly whereas the reflected shock wave from the first plate of the array attenuates less significantly as the shock Mach number increases. The increase in the porosity weakens the suppression effects on the leading shock wave while increases the attenuation rate of the reflected shock wave. The first perforated plate in the array plays a major role in the attenuation of the shock wave.

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Airflow disturbance induced by coal mine outburst shock waves: A case study of a gas outburst disaster in China

Cited by 36 publications

References 21 publications

MLP-Based Model for Estimation of Methane Seam Pressure

MLP-Based Model for Estimation of Methane Seam Pressure

The Airflow Reversal Law in Ventilation System after Coal and Gas Outburst in Tunneling Roadway

Numerical Study of Air Flow Induced by Shock Impact on an Array of Perforated Plates

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