环境条件对柴油池火火行为的影响
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摘要
为了分析不同初始环境条件下柴油池火的火行为,以下衬水垫层、直径D为205 mm的柴油池作为主火源和待引燃火源,通过对火焰温度、热辐射强度和烟气蔓延速度的测试,分析初始环境温度、自然通风和机械通风对柴油池火燃烧特性及安全防火间距的影响。研究结果表明:在自然通风条件下,环境温度越高,柴油池火进入沸溢喷溅阶段越快,辅油盆被引燃的可能性增大。当风速为0.5 m/s时,环境温度为9℃和25℃时柴油池火的安全间距分别应该保持在0.4D和0.6D以上;当风速为1.0 m/s时,两种环境温度下柴油池火的安全间距均应保持在0.8D以上。在所设置的实验条件下,辅油盆被引燃的临界条件是其接收到的辐射热累计达到392.634 k J/m2以上。低风速条件下,环境初始温度越高,柴油池火蔓延的危险性越大;当风速增加到1 m/s时,环境初始温度的影响相对较小,风速对柴油池火蔓延的影响更突出。
In order to analyze the behaviors of diesel pool fire under different ambient conditions,flame temperature,radiant heat flux and smoke spread velocity were tested with the diesel above water cushion layer as the main and target fuel in two Φ205 mm circular stainless steel pans. Results illustrate that,under natural ventilation conditions,diesel pool fire comes into boilover stage earlier,and the target fuel can be ignited more possibly with the increase of ambient temperature. Under0. 5 m/s ventilation velocity,safety distance between diesel pool fires should be over 0. 4 D at 9℃( ambient temperature) and 0. 6 D at 25℃,respectively. When the ventilation velocity is increasedto 1 m/s,safety distance between diesel pool fires should be over 0. 8 D at both 9 ℃ and 25 ℃. The critical heat radiation value should be accumulated to 392. 634 k J/m2 and above to ignite the target fuel. Under lower ventilation velocities,the diesel pool fire spreading become more serious with the increase of ambient temperature. When the ambient velocity is increased to 1 m/s,the effect of ambient temperature on fire spreading is smaller,and the effect of velocity is more significant.
In order to analyze the behaviors of diesel pool fire under different ambient conditions,flame temperature,radiant heat flux and smoke spread velocity were tested with the diesel above water cushion layer as the main and target fuel in two Φ205 mm circular stainless steel pans. Results illustrate that,under natural ventilation conditions,diesel pool fire comes into boilover stage earlier,and the target fuel can be ignited more possibly with the increase of ambient temperature. Under0. 5 m/s ventilation velocity,safety distance between diesel pool fires should be over 0. 4 D at 9℃( ambient temperature) and 0. 6 D at 25℃,respectively. When the ventilation velocity is increasedto 1 m/s,safety distance between diesel pool fires should be over 0. 8 D at both 9 ℃ and 25 ℃. The critical heat radiation value should be accumulated to 392. 634 k J/m2 and above to ignite the target fuel. Under lower ventilation velocities,the diesel pool fire spreading become more serious with the increase of ambient temperature. When the ambient velocity is increased to 1 m/s,the effect of ambient temperature on fire spreading is smaller,and the effect of velocity is more significant.
引文
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[14]涂然,于春雨,肖霞,等.TF5池火平均质量损失速率简化模型及其高原环境下的适用性研究[J].火灾科学,2009,2(1):73-79.
[15]FAY J A.Model of large pool fires[J].Journal of Hazardous Material,2006,136:219-232.
[2]HAMINS A,KLASSEN M,GORGE J,et al.Estimate of flame radiation via a single location measurement in liquid pool fire[J].Combustion Flame,1991,86:223-228.
[3]JENSEN K A,RIPOLL J F,WARY A A,et al.On various modeling approaches to radiative heat transfer in pool fires[J].Combustion Flame,2007,148:263-279.
[4]KRISHNAMOORTHY G.A comparison of gray and non-gray modeling approaches to radiative transfer in pool fire simulations[J].Journal of Hazardous Materials,2010,182:570-580.
[5]MODAK A T.Thermal radiation from pool fires[J].Combustion Flame,1977,29:177-192.
[6]CHEN B,LU S X,LI C H,et al.Initial fuel temperature effects on burning rate of pool fires[J].Journal of Hazardous Materials,2011,188:369-373.
[7]李炎锋,赵威翰,边江,等.城市地下长直隧道火灾近火源区长度确定[J].广西大学学报(自然科学版),2016,41(4):1101-1108.
[8]GAFFAR K,FAISAL K,KELLY H.Modeling of pool fires in cold regions[J].Fire Safety Journal,2012,48:1-10.
[9]WIESER D,JAUCH P,WIUI U.The influence of high altitude on fire detector test[J].Fire Safety Journal,1997,29:195-204.
[10]MOST J M,MANDIN P,CHEN J P.Influence of gravity and pressure on pool fire-type diffusion flames[J].Proceedings of the Combustion Institute,1996,26(2):1311-1317.
[11]FAGN J,YU C Y,TU R.The influence of low atmospheric pressure on carbon monoxide of n-heptane pool fires[J].Journal of Hazardous Materials,2008,154:476-483.
[12]LI Z H,HE Y P,ZHANG H.Combustion characteristics of n-heptane and wood crib fires at different altitudes[J].Proceedings of the Combustion Institute,2009,32(3):2481-2488.
[13]李振华.西藏高原低压低氧条件下可燃物燃烧特性和烟气特性研究[D].合肥:中国科学技术大学,2009.
[14]涂然,于春雨,肖霞,等.TF5池火平均质量损失速率简化模型及其高原环境下的适用性研究[J].火灾科学,2009,2(1):73-79.
[15]FAY J A.Model of large pool fires[J].Journal of Hazardous Material,2006,136:219-232.