Research On Disaster Evolution Of Ventilation System During Coal And Gas Outburst

Exceeding gas,gas explosion and other secondary disasters caused by coal and gas outburst are the urgent problems to be solved in the theory of serious coal mine disasters.In order to research gas overrun,gas explosion and other serious secondary disasters induced by coal and gas outburst,dynamic influence of gas outburst in mine ventilation system and gas transmission process are analysed by using outburst gas component dispersion measurement method and simulation method.A gas concentration sensor to rapid determination of dynamic propagation is built to take the experiment of outburst gas dispersion parameter measurement by establishing ventilation pipeline test experiment and automatic data acquisition system,which is equipped with inventive high resolution CCD optical interference gas detector and super-speed data acquisition card.Gas concentration distribution under different wind speed is obtained by the experiment,gas dispersion deviation coefficient under different wind speed are inversed,and the quantitative relationship between gas dispersion parameter and wind speed is obtained by curve fitting.NC2.0,one of coal and gas outburst simulation softwares in coal mine,which is built combined with transient flow theory,convection mass transfer theory and ventilation network theory are used to reappear the gas outburst and migration process of “10.27” coal and gas outburst accident occurred in Jiulishan coal mine,Jiaozuo city.Outburst source simulation model is built according to the data of gas concentration distribution in 16031 drivage roadway,Jiulishan coal mine 16 mining area.Gas emission intensity is conveyed by flow curve by using unstable II kinds of boundary conditions.Non steady flow and gas distribution of outburst gas in coal mine are simulated by the software,the quantitative relationship between gas dispersion parameter and wind speed is used to make the simulation results agree well with the measured data by constant debugging.Simulation results show that gas outburst source pressure and natural gas pressure are the major factors which lead to airflow changes after outburst.High intensity air flow occurred by coal and gas outburst,which could lead to counter flow in the tunnel.Disorder airflow could occur,airflow reversal in each loop of the system,gas retention in local position and other complex phenomenon could occur under the comprehensive effect of protruding source power and natural gas pressure.Risk areas,which bring harm to the workers,are determined by the applying of coal and gas outburst disaster ventilation simulation software,and gas outburst emergency rescue plans are developed,combined with the automatic control system of mine ventilation.To make gas outburst simulation plan to another heading face in Jiulishan coal mine 16 mining area,and preview the direct infringement area and indirect infringement area which gas could reach dynamically.To analysis zone with gas explosion danger in different outburst intensity quantitatively.Remote automatic air doors are set in the key locations nearby such as working face and yard,so that the high concentration gas produced in outburst could be controlled and dredged in the air return system.Thus avoiding the harm to the workers in working areas from high concentration gas,ensuring the safe evacuation of dangerous areas,trying to minimize disaster losses,reducing secondary disasters such as coal and gas outburst,and improving safety controllable degree to major disasters of coal mines.