Study Of The Numerical Simulation Of The Fire Extinguishing And Prevention With Liquefaction Nitrogen In The Goaf Using Comprehensive Mechanized Caving Method

The top-dropping coal technology of comprehensive mechanized caving in our country, Because the working face with comprehensive mechanized caving method is pushed relatively slowly, so in the goaf the room collapsing is big and coal remains very much and air leak is serious, and also the place of the brackets at the end does not drop the coal of the top, and much coal remains two laneways of the goaf.This causes the fatalness of spontaneous combustion of the remnant coal in the goaf increase and threaten the safety production gravely on the working face with comprehensive mechanized caving method. For adapting to the need of the fire extinguishing and prevention of the working face with comprehensive mechanized caving method, the technology of fire extinguishing and prevention of nitrogen is extended step by step in the homeland. The dissertation bases on the unified equation of heat-transferred and value-transferred of the dissolute in the goaf and the working face. According to the experiment of falling temperature with liquefaction nitrogen on the floor, and uniting the idiographic conditions of 3315 working face with comprehensive mechanized caving method of Hai zhou Mine, Carrying through numerical simulation using PHOENICS, the fields of temperature and concentration of every component gas(oxygen and nitrogen) after injecting nitrogen. It has very important significance to the forecast analyses and effect estimates for the fire extinguishing and prevention of the goaf with liquefaction nitrogen, and very important to guide the reality of the fire extinguishing and prevention in the spot goaf with liquefaction nitrogen.