Numerical Simulation Study on Fire Preventing and Extinguishing Technology by Dry Ice in Mined Area

In order to realize fire prevention and extinguishing technology that the low-temperature dry ice releases carbon dioxide in mined area, the numerical simulation method of Fluent is adopted. Through establishing three-dimensional model of seepage and concentration field of the dry ice staying in the goaf, we study the migration laws of low-temperature carbon dioxide released from dry ice storage release device in mined area and the influence of low-temperature carbon dioxide on spontaneous combustion "three zones". The results show that low-temperature carbon dioxide spreads to the return air side from the release point and then full of mined area. After 16 days, the concentration distribution gets steady. The highest concentrations is up to 35% at the inlet side of the mined area that is 40 m to 60 m away from the working face, and the concentration of the return air side is also more than 10%. Correspondingly, oxygen concentration of the whole mined area decreases, especially in the inlet side. The maximum width of oxidation and heat accumulation zone moves from the inlet side to the middle of mined area.