不同低气压环境下甲醇和乙醇池火燃烧特性的实验研究
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
人们研究火灾科学的主要目的是为了防火和灭火,很多专家对常压环境下的防火灭火技术已经做了很多系统的研究,并针对常压火灾防治提出了很多有用的方法,而对各类海拔较高的城市的防火灭火技术却缺乏相关的理论技术指导,例如中国的西藏拉萨等高原城市建有众多的古文化建筑,最著名的当属布达拉宫,这些建筑中可燃物和火灾危险热源都非常多,极易发生火灾,而且一旦发生火灾也难以扑救,所以对低气压低氧浓度环境下的各种典型可燃物的燃烧特性的研究,已经得到了国内外专家学者的一致重视。
     本文主要在位于合肥中科大火灾实验室的“低氧低压模拟试验箱”中展开甲醇和乙醇池火的实验研究,此试验箱可以比较真实的模拟各种低气压环境。
     通过研究发现,随着气压的降低,质量燃烧速率也变低,火源的单位面积质量燃烧速率与气压大小呈现幂函数关系;随着气压的降低,羽流温升下降的趋势变缓,同时将羽流高温区域往上方推移
     甲醇和乙醇的火焰高度和火焰面积变化特征类似,随着气压变化,呈现先上升再下降的特征。在浮力控制的火焰高度随气压升高而减小阶段,甲醇池火中工况一火焰高度L∝P~(-0.52),工况二火焰高度L∝P~(-0.51),乙醇池火中工况一火焰高度L∝P~(-0.36),工况二火焰高度L∝P~(-0.39),随着气压的降低,工况二中的火焰面积受气压影响作用较工况一的大;在扩散输运控制的火焰高度随气压升高而增大阶段,由于试验箱内氧气含量较低,不足以达到充分燃烧的化学当量比,燃烧减缓,这一过程Burke–Schumann火焰分析可以很好的描述。
     在火焰高度极大值附近,质量燃烧速率的变化率是不一样的。
     影响火焰高度变化的主要因素有环境压力、燃料类型、油盘尺寸、火源形状因子;火源形状因子超过一定临界值时,会出现分叉现象,且环境气压越大,分叉现象就越明显。
The main purpose of research on fire science is fire prevention and fire extinguishment. A lot of experts had made much systematic research on fire protection and fire fighting techniques under ordinary ambient pressure condition which put forward a lot of effective methods, However, the theoretical guidance of fire fighting techniques in the cities of high altitude is still lack. For example, there are plenty of historic buildings on the Tibet plateau, including the Potala Palace. In these buildings, there are so many combustible materials that are quite easy to catch fire. These fires are difficult to be extinguished. Therefore, the combustion characteristic of typical combustible materials under low air pressure and low-oxygen atmosphere on the plateau had been drawn seriously attention by the experts all around the world.
     A low-oxygen and low-air pressure simulation box, in which various low pressure can be acquired accurately, has been established in State Key Laboratory of Fire Science of USTC in Hefei. In this paper, some experiments of methanol and ethanol pool fire are carried out in the experiment box.
     It is found that with the pressure decreases, the mass burning rates is also decreasing through experiments. The burning rates of methanol and ethanol are proportional to the atmosphere pressure, according with a power function distribution relationship. With the pressure decreases, the dropping rate of plume centerline temperature is becoming slower and also the hot zone of the plume went upward at the same time.
     The variation of flame height and flame area of methanol and ethanol pool fire is similar. The value of flame height and flame area increase with the rise of the atmosphere pressure until a turning point is reached. After that they decrease with the increment of the atmosphere pressure. In the buoyancy-controlled phase, in which the flame height decreases as the air pressure increases, the flame height of methanol pool fire is following the rule of L∝P~(-0.52) in condition one and it also fits well with the rule of L∝P~(-0.51) in condition two. The flame height of ethanol pool fire follows the rule of L∝P~(-0.36) in condition one and accords to the rule of L∝P~(-0.39) in condition two. The effect of air pressure on the flame area is more obvious in condition two rather than condition one. In the mechanism of diffusion and transport-controlled phase, in which the flame height increases as the air pressure increases, since the concentration of oxygen is low in experiment box, combustion will not reach the stoichiometric ratio and slows down. This process can be described well by the "Burke–Schumann" flame analysis.
     The differential mass burning rates are different around the maximum flame height areas.
     The main factors that affect the flame height are consisted of ambient pressure, fuel type, the size of oil container and aspect ratio. The shape of fire will become bifurcation while the aspect ratio exceeds a certain critical value. The bifurcation will be more obvious with higher pressure.
引文
[1] Thomas PH, Hinkley PL,Theobald CR., Simms DL. Investigations into the Flow of Hot Gases in Roof Venting[J] . Fire Research Technical Paper No. 7, HMSO, London, 1963.
    [2] L.Audouin G. Kolb JL.Torero.etc.Average Centerline Temperature of a Buoyant Pool Fire Obtained by Image processing of Video Recordings[J].Fire Safety Journal,1995,24:167-187
    [3] Cetegen BM, Ahmed TA. Experiments on the periodic instability of buoyant plumes and pool fires[J]. Combustion and Flame, 1993, 93(1-2):157-184
    [4] Most JM, Mandin P, Chen JP. Joulain.Influence of gravity and pressure on pool fire-type diffusion flames [C].Proceedings of the 26th Symposium (International) on Combustion, The Combustion Institute, pp. 1311– 1317.
    [5] Wieser D, Jauch P, WiUi U.The Influence of High Altitude on Fire Detector Test.Fire Safety Journal [J] , 1997, 29: 195-204.
    [6] Fang Jun,Yu Chun-Yu,Tu Ran.The influence of low atmospheric pressure on carbon monoxide of n-heptane pool fires [J] .Journal of Hazardous Materials. 2008, 154: 476–483.
    [7] Zhen-hua Li, Yaping He, Hui Zhang.Combustion characteristics of n-heptane and wood crib fires at different altitudes [C] .Proceedings of the Combustion Institute 2009, 32: 2481–2488.
    [8]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
    [9]孙晓乾,李元洲,霍然,曾文茹,李思成,叶永飞.西藏古建筑常用木材的着火特性试验[J].中国科学技术大学学报,2006.1
    [10] SUN Xiaoqian, LI Yuanzhou, HUO Ran, ZENG Wenru, REN Binbin, LI Kaiyuan, YE Yongfei.Comparison on Generation Principle of Carbon Monoxide Concentration in Pine Combustion between Plain and Altiplano Regions[C].18th International Symposium on Analytical and Applied Pyrolysis, May,2008
    [11]孙晓乾,李元洲,霍然,胡隆华,李开源.基于羽流中CO浓度分析木材燃烧过程的实验研究[C].中国工程热物理学会燃烧学分会2008年年会,2008.10.
    [12]任彬彬,李元洲,徐伯乐,涂然.大气压力对于木材着火模型的影响研究[C].中国工程热物理学会学术会议论文,2010
    [13]任彬彬.高原环境下木材着火特性及油池火羽流特性研究[D].合肥:中国科学技术大学,2009
    [14]涂然,于春雨,肖霞,方俊,王进军,张永明.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年第2期,73~79.
    [15]徐伯乐.高原环境下油池火的火焰及羽流特性研究[D].合肥:中国科学技术大学,2010
    [1]廖光煊,王喜世,秦俊.热灾害实验诊断方法.中国科学技术大学出版社[M].合肥:2003
    [2]任彬彬.高原环境下木材着火特性及油池火羽流特性研究[D].合肥:中国科学技术大学,2009
    [1]陈志斌,胡隆华,霍然,祝实.基于图像亮度统计分析火焰高度特征的研究.燃烧科技与技术,2008年06期.
    [2]庄磊,陆守香,孙志友,汪金辉,康泉胜.航空煤油池火焰高度特征研究.中国科学技术大学学报,2009年07期
    [3]王家文,曹禺.MATLAB6.5图形图像处理.北京:国防工业出版社,2004.
    [4]张德丰等.MATLAB数字图像处理.北京:机械工业出版社,2009.
    [5]王正林,刘明.精通MATLAB7.北京:电子工业出版社,2006
    [6]霍然,胡源,李元洲.建筑火灾安全工程导论[M] .合肥:中国科学技术大学出版社,1999.
    [7] Thomas P H,Webster C T,Raftery M M.Experiments on Buoyant Diffusion Flames[J]. Combustion and Flame, 1961, 5(1): 359-367.
    [8] Zukoski E E. Properties of Fire Plumes. Combustion Fundamentals of Fire[M]. London: Academic Press, 1995.
    [9] Heskestad G. Fire Plumes. SFPE Handbook of Fire Protection Engineering, 2nd Ed [M]. Nat. Fire Protection Assoc., 1995.
    [10]徐伯乐.高原环境下油池火的火焰及羽流特性研究[D].合肥:中国科学技术大学,2010
    [11] Karlsson B, Quintiere J G. Enclosure fire dynamics[M]. Florida: CRC Press LLC,2000.
    [12] Pagni P J. Pool vortex shedding frequencies[J]. Applied Mechanics Review,1990, 43(1):153-170.
    [13] Bejan A. Predicting the pool fire vortex shedding frequency[J]. Journal of Heat Transfer, 1991,113(1): 261-263.
    [14] Cetegen B M, Ahmed T A. Experiments on the periodic instability of buoyant plumes and pool fires[J]. Combustion and Flame,1993, 93(1-2):157-184.
    [15] Cetegen B M. Entrainment in the near and far field of fire plumes[J]. Combustion Science and Technology, 1984. 39(1-6):305-331.
    [16] Cetegen B M. A phenomenological model of near-field fire entrainment[J]. Fire Safety Journal, 1998, 31(4): 299-312.
    [17] Cetegen B M. Integral analysis of planar and axisymmetric steady laminar buoyant diffusion flames[J]. Combustion Theory and Modelling, 1999, 3(1): 13-32.
    [18] Cetegen B M, Y Dong. Experiments on the instability modes of buoyant diffusion flames and effects of ambient atmosphere on the instabilities [J]. Experiments in Fluids, 2000, 28(2-6): 546-558.
    [19]徐伯乐,李元洲,毛少华,匡萃芃,花荣胜,祝实.西藏高原环境下油池火的燃烧速率和振荡频率实验研究[J],燃烧科学与技术,2011,17(3),1-7
    [1] Thomas PH,Webster CT,Raftery MM. Experiments on Buoyant Diffusion Flames[J]. Combustion and Flame,1961,5(1): 359-367.
    [2] Zukoski EE.Properties of Fire Plumes. Combustion Fundamentals of Fire[M].London: Academic Press, 1995.
    [3] Heskestad G.Fire Plumes.SFPE Handbook of Fire Protection Engineering,National Fire Protection Association, Quincy, MA, 1995.
    [4] Karlsson B,Quintiere JG. Enclosure fire dynamics[M]. Florida: CRC Press LLC, 2000.
    [5] L.H. Hu, S. Liu, W. Peng, R. Huo, Experimental study on burning ratess of square/rectangular gasoline and methanol pool fires under longitudinal air flow in a wind tunnel[J]. Journal of Hazardous Materials. 2009,169:972-979.
    [6] J.-M. Most, P. Mandin, J. Chen, P. Joulain, Influence of gravity and pressure on pool fire-type diffusion flames, [C] Proceedings of the 26th Symposium (International) on Combustion, The Combustion Institute, pp. 1311– 1317.
    [7] D. Wieser, P. Jauch & U. WiUi, The Influence of High Altitude on Fire Detector Test, Fire Safety Journal [J], 1997, 29: 195-204.
    [8] Fang Jun, Yu Chun-Yu, Tu Ran, The influence of low atmospheric pressure on carbon monoxide of n-heptane pool fires [J], Journal of Hazardous Materials. 2008, 154: 476–483.
    [9] Zhen-hua Li, Yaping He , Hui Zhang, Combustion characteristics of n-heptane and wood crib fires at different altitudes [C], Proceedings of the Combustion Institute 2009, 32: 2481–2488.
    [10] Xiao-kang Hu, Yaping He, Zhen-hua Li, Jian Wang, Combustion characteristics of n-heptane at high altitudes [C], Proceedings of the Combustion Institute. 2011, 33: 2607–2615.
    [11]徐伯乐.高原环境下油池火的火焰及羽流特性研究[D].合肥:中国科学技术大学,2010
    [12]蔡昕,王喜世,李权威,廖光煊,低气压环境下正庚烷及汽油池火的燃烧特性[J].2010,16(4):341-346.
    [13]涂然,于春雨,肖霞,方俊,王进军,张永明.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,2009,2,73~79.
    [14] Jean-michel most, Pkilippe Mandin, Jie Chen ,Pierre Joulain, Influence of gravity and pressure on pool fire–type diffusion flames [C], Twenty-Sixth Symposium (International) on Combustion/The Combustion Institute, 1996, 1311–1317
    [15] Williams, F. A., Combustion Theory [M], Benjamin Cummings, Menlo Park, Calif., 1985.
    [16] R.L. Alpert, Pressure modeling of fires controlled by radiation [C], Proceedings of the 15th Symposium on Combustion, August 15–20, MIT, Cambridge, MA, The Combustion Institute, Pittsburgh, PA, 1976, pp. 1489–1500.
    [17] V.I. Blinov, G.N. Khudiakov, U.S. Army Translation, NTIS No. AD296762, 1961.
    [18] V. Babrauskas, Estimating large pool fire burning ratess [J], Fire Technology. 19 (1983) 251–261.
    [19] H. Koseki, G.W. Mulholland, The effect of diameter on the burning of crude oil pool fires [J], Fire Technology. 27 (1) (1991) 54–65.
    [20] K.S. Mudan, Thermal radiation hazards from hydrocarbon pool fires [J], Progress Energy Combustion and Science. 10 (1984) 59–80.
    [21]陈志斌,胡隆华,霍然,祝实.基于图像亮度统计分析火焰高度特征的研究[J],燃烧科学与技术,2008,14(6), 557-561.
    [22]庄磊,陆守香,孙志友,汪金辉,康泉胜.航空煤油池火焰高度特征研究[J],中国科学技术大学学报,2009, 39(07) :763-768.
    [23]霍然,胡源,李元洲.建筑火灾安全工程导论[M] .合肥:中国科学技术大学出版社, 2009.
    [24]徐伯乐,李元洲,毛少华,匡萃芃,花荣胜,祝实.西藏高原环境下油池火的燃烧速率和振荡频率实验研究[J],燃烧科学与技术,2011,17(3),1-7
    [1] Thomas PH,Webster CT,Raftery MM. Experiments on Buoyant Diffusion Flames[J]. Combustion and Flame,1961,5(1): 359-367.
    [2] Zukoski EE.Properties of Fire Plumes. Combustion Fundamentals of Fire[M].London: Academic Press, 1995.
    [3] Heskestad G.Fire Plumes.SFPE Handbook of Fire Protection Engineering,National Fire Protection Association, Quincy, MA, 1995.
    [4] Karlsson B,Quintiere JG. Enclosure fire dynamics[M]. Florida: CRC Press LLC, 2000.
    [5] L.H. Hu, S. Liu, W. Peng, R. Huo, Experimental study on burning ratess of square/rectangular gasoline and methanol pool fires under longitudinal air flow in a wind tunnel[J]. Journal of Hazardous Materials. 2009,169:972-979.
    [6] J.-M. Most, P. Mandin, J. Chen, P. Joulain, Influence of gravity and pressure on pool fire-type diffusion flames, [C] Proceedings of the 26th Symposium (International) on Combustion, The Combustion Institute, pp. 1311– 1317.
    [7] D. Wieser, P. Jauch & U. WiUi, The Influence of High Altitude on Fire Detector Test [J], Fire Safety Journal, 1997, 29: 195-204.
    [8] Fang Jun, Yu Chun-Yu, Tu Ran, The influence of low atmospheric pressure on carbon monoxide of n-heptane pool fires [J], Journal of Hazardous Materials. 2008, 154: 476–483.
    [9] Zhen-hua Li, Yaping He , Hui Zhang, Combustion characteristics of n-heptane and wood crib fires at different altitudes [C], Proceedings of the Combustion Institute 2009, 32: 2481–2488.
    [10] Xiao-kang Hu, Yaping He, Zhen-hua Li, Jian Wang, Combustion characteristics of n-heptane at high altitudes [C], Proceedings of the Combustion Institute , 2011, 33: 2607–2615.
    [11]徐伯乐.高原环境下油池火的火焰及羽流特性研究[D].合肥:中国科学技术大学,2010
    [12]蔡昕,王喜世,李权威,廖光煊,低气压环境下正庚烷及汽油池火的燃烧特性[J].2010,16(4):341-346.
    [13]涂然,关劲夫,王彦,方俊,王进军,张永明.高原低压环境小尺寸乙醇池火辐射特性的变化[J].燃烧科学与技术,2011,1,62~66.
    [14]涂然,雷佼,王彦,方俊,王进军,张永明.利用压力相似预测高原低压环境小尺寸池火燃烧速率的变化特性[J],燃烧科学与技术,2010,16(5), 467-471.
    [15] Jun Fang , Ran Tu, Jin-fu Guan, Jin-jun Wang, Yong-ming Zhang. Influence of low air pressure on combustion characteristics and flame pulsation frequency of pool fires [J], Fuel, 2011, doi:10.1016/j.fuel.2011.03.035
    [16] Jean-michel most, Pkilippe Mandin, Jie Chen ,Pierre Joulain, Influence of gravity and pressure on pool fire–type diffusion flames [C], Twenty-Sixth Symposium (International) on Combustion/The Combustion Institute, 1996, 1311–1317
    [17] Williams, F. A., Combustion Theory [M], Benjamin Cummings, Menlo Park, Calif., 1985.
    [18] R.L. Alpert, Pressure modeling of fires controlled by radiation [C], Proceedings of the 15th Symposium on Combustion, August 15–20, MIT, Cambridge, MA, The Combustion Institute, Pittsburgh, PA, 1976, pp. 1489–1500.
    [19] V.I. Blinov, G.N. Khudiakov, Diffution burning of liquids [M], U.S. Army Translation NTIS .No. AD 296762, 1961.
    [20] V. Babrauskas, Estimating large pool fire burning ratess [J], Fire Technology. 19 (1983) 251–261.
    [21] H. Koseki, G.W. Mulholland, The effect of diameter on the burning of crude oil pool fires [J], Fire Technology. 27 (1) (1991) 54–65.
    [22] K.S. Mudan, Thermal radiation hazards from hydrocarbon pool fires [J], Progress Energy Combustion and Science. 10 (1984) 59–80.
    [23]陈志斌,胡隆华,霍然,祝实.基于图像亮度统计分析火焰高度特征的研究[J],燃烧科学与技术,2008,14(6), 557-561.
    [1]陈志斌,胡隆华,霍然,彭伟,祝实.矩形油池火羽流中心线的温度分布[J],燃烧科学与技术,2009,15(3), 249-253.
    [2] Hasemi Y, Nishata.M. Fuel shape effect on the deterministic properties of turbulent diffusion flames [ C ] Proceed ing of the Second International Symposium, Fire Safety Science. 1989: 275-284.
    [3] Jean-michel most, Pkilippe Mandin, Jie Chen ,Pierre Joulain, Influence of gravity and pressure on pool fire–type diffusion flames [C], Twenty-Sixth Symposium (International) on Combustion/The Combustion Institute, 1996, 1311–1317
    [4]陈志斌,胡隆华,霍然,祝实.基于图像亮度统计分析火焰高度特征的研究[J],燃烧科学与技术,2008,14(6), 557-561.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700