非离子液细水雾灭火效能与减弱火焰强化现象研究

Study on the fire-fighting effect and weakening of flame intensification of non-ionic liquid water mist

针对细水雾释放初期出现的火焰强化在一定程度上影响细水雾灭火技术的安全适用性问题,基于物理化学、火灾学理论,开展了弱化火焰强化的非离子液添加剂遴选和熄灭油池火的试验。结果表明:非离子液细水雾释放时具有较佳的雾化特征参数,其灭火时间和最高温度增加幅度均随非离子液质量分数的增大而降低;火灾烟气中CO体积分数最大值和维持高CO体积分数的时间均随非离子液质量分数的增大而降低;O_2体积分数降低到最小值和由最小值恢复至常值的恢复速率均随非离子液质量分数的增大而加快。非离子液细水雾具有弱化火焰强化的作用,且扑灭油池火的能力优于纯水细水雾,通过分析,获得了非离子液细水雾弱化火焰强化的机理。其主要灭火机理:一是非离子液细水雾喷出后形成的悬浮气泡和水泡沫具有阻隔热辐射、隔断O_2供应和隔离可燃物与O_2接触的作用;二是非离子液具有较低的HLB值,且细水雾因高温作用,与水分子以氢键链接的醚基断裂,增强了捕捉煤油分子和销毁链式反应中H·和OH·的能力。上述研究成果,对于细水雾灭火技术在油品火灾的高效、安全扑救方面具有重要意义。

The phenomenon of flame intensification during fire extinguishing in the initial stage of exerting water mist influences the safety applicability of the fire-extinguishing technology of water mist.Based on the theories of physical chemistry and fire science,non-ionic liquid additives for weakening the phenomenon of flame intensification were chosen,and then a series of experiments extinguishing oil pool fire were carried out by the water mist containing non-ionic liquid additives with different mass fractions.The results showed that the water mist containing non-ionic liquid additive had better atomization characteristic parameters during fire extinguishing.The extinguishing time and the increase amplitude of maximum temperature were shortened with the increase of mass fraction of non-ionic liquid.The maximum volume fraction of CO and the time for maintaining high CO volume fraction in the fire smoke decreased with the increase of non-ionic liquid mass fraction,while the minimum volume fraction of the O 2 and the recovery rate from the minimum value to the constant value increased with the increase of the non-ionic liquid mass fraction.The non-ionic liquid water mist had the function of weakening the flame intensification,and its ability to extinguish the oil pool fire was better than the pure water fine water mist.The mechanism was obtained from the non-ionic liquid water mist weakening the flame strengthening.The main fire extinguishing function was as follows:firstly,the suspended air bubbles and water bubbles formed after the non-ionic liquid water mist sprays had the functions of blocking heat radiation,blocking the supply of oxygen and isolating combustibles from oxygen.Secondly,non-ionic liquid water mist had a low HLB value of breaking ether groups under high temperature,which enhanced the ability to capture kerosene molecules and destroy H·and OH·radicals in the chain reaction.The results had a great significance for water mist fire extinguishing technology in the efficient and safe combat of oil fires.