采空区液态CO2降温规律模拟研究OA

Liquid CO2 is more and more used in mine fires in order to further improve the fire prevention and extinguishing efficiency of liquid CO2.In this paper,a three-dimensional numerical model of goaf is established based on the research background of a working face in Yangchangwan Coal Mine.By changing the injection flow rate,injection time and air speed of liquid CO2,the influence of CO2 injection parameters on the cooling range is studied.The results show that the range below 0℃increases with the increase of injection flow rate.When the injection flow rate increases from 2.5 kg/s to 7 kg/s,the range below 0℃increases by 45.7 times,and the range of CO2 concentration higher than 50%increases by 40 times.With the increase of air speed,the air speed increases from 0.3 m/s to 1 m/s,the range below 0℃decreases by 79.1%,and the range above 50%of CO2 concentration decreases by 78.9%.Prolonging the injection time can increase the range below 0℃.Combined with the air distribution and cooling inerting performance requirements of Yangchangwan working face,it is determined that when the air speed of the working face is 0.5～0.8 m/s,the optimal pressure injection flow of liquid CO2 is 5～7 kg/s,and the injection duration is 4～5 h.The research results provide a theoretical basis for the development of liquid CO2 fire prevention measures in the working face of Yangchangwan Coal Mine.