Research Of The Liquid CO₂ Injection For Fire Prevention And Extinguishing In The Open Goaf

Carbon dioxide fire extinguishing technology is a widely used technique preventing and extinguishing fire, with rapid fire, significant effect, safe and reliable, simple operation, has received widespread attention at home and abroad, through theoretical analysis, numer ical simulation and field application of a combination of methods, by theoretical analysis and numerical simulation for the pilot to simulate liquid carbon dioxide in open mining goaf in migration, and the industrial experiment, industrial experiment results and the simulation results are in good agreement, optimize the site liquid carbon dioxide injection process.First, according to the liquid CO₂ fire prevention and extinguishing characteristics of liquid CO₂ fire prevention and extinguishing technology, comprehensive analysis of liquid CO₂ direct injection type and liquid CO₂ vaporizing process characteristics and existing problem, and presents a 130215 fully mechanized working face in the use of the direct injection technology of fire prevention and extinguishing. Secondly, the mined out area overlying strata collapse colony characteristics, vertical three zone height research and analysis, to study on the goaf in coal and rock broken expand coefficient, porosity, permeability and viscous resistance coefficient between the relationship and characteristics of distribution in the goaf in, provides an important basis for the preparation of porosity and viscous resistance coefficients defined function?UDF?. Then, based on the basic equation of gas flow in the goaf, the air flow model was established to simulate the gas concentration field and velocity field in the goaf, and the flow pattern of the liquid CO 2 in the goaf was obtained. The effect of the injection position on the gas migration law in the goaf wa s analyzed, the optimum position range of the liquid CO₂ was obtained, and the effect of the liquid CO₂ on the gas concentration in the working face was analyzed. Finally, combined with the theoretical analysis and numerical simulation results, and the actual drilling location of the CO₂ injection was determined according to the Shenhua N ingxia coal industry group sheep farm Bay coal natural combustion, optimized for field liquid CO₂ injection process. Through the gas monitoring surface concentration, analyzes the inertia effect of liquid CO₂ injection on the face, goaf.