Theoretical model and numerical method on the law of gas flow in coal and gas outburst

被引：0
|
作者：
Hao Z. [1 ]
Jian K. [1 ,2 ]
Peng S. [2 ]
Xu J. [2 ]
Qin J. [3 ]
机构：
[1] Aerospace and Engineering College, Chongqing University, Chongqing
[2] State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing
[3] Chongqing Vocational Institute of Engineering, Chongqing
来源：
Meitan Xuebao/Journal of the China Coal Society | 2020年 / 45卷
关键词：
Coal and gas outburst; Finite volume method; Gas state; Law of gas flow;
D O I：
10.13225/j.cnki.jccs.2019.1485
中图分类号：
学科分类号：
摘要：
Coal and gas outburst, which is a kind of disaster in coal mines and has a great threat to the safety of coal production, has complex mechanical mechanism and strong destructiveness.Up to now, the study on coal and gas mechanism is still in the stage of exploration.Scholars generally believe that in-situ stress, gas pressure and physical properties of coal lead to the outburst initiation.As one of these three elements, gas plays an important role in coal and gas outburst.Therefore, it is of great significance to study the rule of gas flow in coal and gas outburst.It is generally known that coal and gas outburst is a dynamic process.Hence, the understanding on the rule of gas flow in coal and gas outburst from a mechanical point of view can better explain the main role of gas in coal and gas outburst.Based on the percolation theory of porous media, the governing equation, which is an unsteady and nonlinear partial differential equation, is developed in outburst process.This governing equation is discretized by the finite volume method, the discrete form of which is a system of nonlinear equations.The numerical solution obtained by a quasi-Newton method is agreed with experimental data well.The permeability of the coal sample in outburst process is determined by the bisection method and experimental data.With respect to the permeability measured in the laboratory, the permeability increases dramatically in outburst process.Based on this governing equation, the change laws of gas pressure, gas pressure gradient and gas velocity in coal and gas outburst are analyzed.In the whole process of outburst, the maximum gas pressure gradient always appears near the hole and the gas pressure gradient decays rapidly. Combined with the experimental phenomenon, it can be shown that gas pressure gradient is a key factor dominating the outburst initiation and termination. © 2020, Editorial Office of Journal of China Coal Society. All right reserved.
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页码：833 / 840
页数：7
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