基于FDS的矿井巷道火灾烟气致灾的数值模拟

Numerical Simulation of Smoke Disaster Caused by Mine Roadway Fire Based on FDS

巷道火灾时期,烟气流动受各种因素影响复杂多变,为研究火灾期间烟气扩散规律及致灾特性,基于FDS对"L"型巷道进行数值模拟,同时参考《煤矿安全规程》规定风速,重点模拟1.92 MW和2.7 MW火源功率下,0.25~2.1 m/s风速内巷道火灾烟气蔓延和温度分布变化情况。结果表明:火源功率和风速对烟气扩散影响较大,下风侧排烟速度与火源热释放速率值和风速正相关。由于存在临界风速,热释放速率与上风侧烟流滚退存在差异性关系。风速过低时,上风侧烟气扩散速度取决于大火源功率;当风速提高到临界风速,火源功率对烟气逆流速度与距离影响减小甚至消失。巷道温度受火源功率和风速影响变化一致,温度自巷道火区向两侧递减,但大火源功率巷道温度整体高于低火源功率。

Smoke flow is affected by various factors during the roadway fire.To study the law of smoke diffusion and disasters during fire period,the numerical simulation for L-type roadway based on FDS is carried out.Refer to the wind speed specified in the Safety Regulations for Coal Mines,flue gas spread,temperature and CO concentration changes in mine fires at wind speed range of 0.25 m/s to 2.1 m/s under 1.92 MW and 2.7 MW fire source power are simulated.The results show that the fire source power and the wind speed have great influence on the smoke diffusion,and the leeward side exhaust velocity is positively correlated with the fire source heat release rate and wind speed.Due to the existence of critical wind speed,the heat release rate has a different relationship with the backflow of smoke in the windward side.When the wind speed is too low,the flue gas diffusion velocity on the windward side depends on the power of the large fire source;when the wind speed increases to the critical wind speed,the influence of the fire source power on the flue gas reverse flow velocity and distance decreases or even disappears.The temperature of the roadway is consistent with the influence of the fire source power and the wind speed.The temperature decreases from the fire zone of the roadway to both sides,but the temperature of the large fire source power tunnel is higher than that of the low fire source power.