Research On Control Mechanism And Remote Rescue System For Coal Thermodynamic Disaster

Mine fire and gas explosion are the major disasters which coal mines facing inChina, the disasters often cause heavy casualties and property losses, but also maytrigger secondary disasters. Based on characteristics of the large difficulty coefficient,high technical requirements, and high risk in the process of an accident relief. Usingtheories of the ventilation systematics, fluid dynamics, combustion andthermodynamics, explosion dynamics. A large number of experiments, numericalsimulation and theoretical analysis on the mine thermal power disaster have beendone, and the control mechanism and the key scientific issues involved in theconfiguration of the emergency rescue equipment were studied. Innovative resultswere achieved as followed:This paper analyzed the spread model, combustion products and hazards of allkinds of combustibles in the intake airflow roadway. Formula of fire spread speeed onthe conditions of downstream, reflux, and different inclination were derived, and themigration law of gas flow diffusion and spread in the roadway were analyzed. By thedimensionless analysis on backflow distances of smoke, the modified dimensionlessformula of backflow distances of smoke was concluded, and critical wind speed wascalculated under certain conditions.Principle of remote rescue system for intake airflow roadway fire of complexventilation system was researched. The idea on the transformation from passivedisaster resistance to active relief in catastrophic process was put forward. Thedistance of smoke backflow under different airflow speed and heat release rate in thedrift fire disaster was simulated by FDS and the three-parameter relationship wasexpressed as L=19.43*ln0.911*QD/v~3. The critical wind speed was calculated andcompared with the experimental fitting formula to obtain the best parameter settings,and the law of smoke backflow under the same combustion parameters and differentinclination in the section of the roadway was simulated.3D roadway network modelwas established based on the actual ventilation system to simulate and analyze laws offire spread, path of the plume movement and temperature distribution before and afterthe startup of remote rescue system. It proved useful and feasibile of the configurationof remote rescue system, and versatile of numerical simulation.According to the working principle of remote rescue system in main intake fire,this paper presented air distribution methods to ensuring the high efficientfire-fighting in smoke flow zone and safety evacuation in non-smoke flow zone during disasters. Numerical simulation and theoretical calculation methods were usedto calculate the air quantity suppressing fire spread and smoke backflow, whichensured the air quantity in non-smoke flow reach60%of the original air volume andset the optimal air distribution threshold value for the key roadways in the reliefprocess. Monitoring subsystem of air quantity parameters was established based onsimplified network of disaster relief system. Iterative solution was used to inverse thedynamic value of fire pressure by simplifying network, which was substituted into theventilation network to get the dynamic results of the air quantity for each branch inthe relief process. The adjustable air doors were designed to remotely control theopening of air doors and achieve the optimal air quantity distribution.Based on the research of gas explosion propagation mechanism and damageeffects on the surrounding ventilation and the ideas of recovering ventilation system,we put forward the idea on selectively pre-buried "normally open" air doors in thearea where gas explosion probably might occur and positions where ventilationfacilities were easily damaged. Air doors could close automatically once disasterhappened. Local ventilation system model for gas explosion happening frequently wasestablished,to test the destructive effect on the ventilation facility of weak face indifferent locations and different ways of roadway configuration. According to theoverpressures and destroyed pieces of weak face, the priority of the destruction ofventilation facilities was determined, which provided references for theexplosion-proof configuration for ventilation facilities.According to the characteristics of roadway fire relief and ventilation systemrecovery after gas explosion happened and equipments of control methods for rescueequipments, intrinsically safe and flame proof controller based on PLC and opticalcommunications and ground supervising center were developed to dynamicallymonitor positions with frequently occurring disasters, regional air quantity, on-offstate and opening range of air doors. We designed air doors with anti-trap,non-deformability from roadways and the adjustable opening. Gas compressionunderground and alternate gas cylinders with high pressure provided a sort of doublesecure affirmance for air doors opening and closing. External power and spare batteryalso provided a sort of double secure affirmance for remote rescue system. Softwareof ground supervising center and the host computer were developed to realize a sort ofthree secure affirmance of remotely manual control, intelligent control and automaticcontrol, control remotely and intelligently air quantity of air network in rescue and diplay dynamically air quantity of airflow branches. The remote rescue system wasdesigned and installed at the Longdong Coal Mine and achieved the good effects ofremotely intelligent control for air quantity in relief process by exercise in the pit.According to actual situations on-site of the remote rescue system in three coal minesof Longdong, Changcun and Anjialing No.2Coal Mine, we analyzed theirconfiguration scheme, working principle and application effects of remote rescuesystem.The research results provided theoretical foundation and a technology for remoterescue system for coal thermodynamic disaster, and a guarantee for life safety of theunderground staff. It has important theory meaning and practice value for the futureconfiguration of the underground ventilation facilities and underground emergencyrescue for disasters. In addition, there were10papers (3EI articles and3EI articlesincluded in EI source journals soon) dealing with the subject.