瞬态发射光谱法研究正十二烷燃烧反应特性
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摘要
采用加热激波管和增强型CCD瞬态光谱测量系统,在波长范围200~900nm,点火压力4.0atm,点火温度(1 200~1 300)K,当量比0.5、1.0和2.0的条件下,实时测得了正十二烷/空气和正十二烷/氧气/氩气燃烧过程的瞬态发射光谱.结果表明:燃烧过程在此波段内的主要发射光谱带归属于反应中间产物OH、CH和C2自由基;在不同当量比条件下,燃烧过程中OH(306.4nm)/CH(431.4nm)/C2(516.4nm)的光谱强度显著不同,贫油情形有利于OH自由基生成,富油情形有利于C2自由基生成;浴气的不同会导致燃料燃烧温度的不同,从而引起燃料燃烧发射光谱的不同.所测燃烧反应自由基的时间分辩光谱直观反映出正十二烷燃烧过程中重要中间产物OH、CH和C2的变化情况.研究结果有助于认识正十二烷燃烧反应特性和验证其燃烧反应机理.
Using a heated shock tube and an intensified spectroscopic detector CCD,transient emission spectra of n-dodecane in the combustion reaction were measured in the range of 200~900 nm.Experiments were conducted at pressure of 4.0atm,temperatures of(1 200~1 300)K,equivalence ratios of 0.5,1.0,and 2.0.Results show that the main emission bands are attributed to OH,CH and C2 radicals produced during the combustion process.In the different equivalence ratios,the emission intensities of OH(306.4 nm)/CH(431.4 nm)/C2(516.4 nm)are significantly different in the combustion process,which indicates that fuel-lean situation is good for generation of OH radicals,and fuel-rich situation is good for C2.Different diluent gases lead to different combustion temperatures when the fuel burns,which causes the different patterns of the emission spectra of the fuel.The variation of OH,CH and C2 radicals produced in the combustion of n-dodecane are shown clearly by the time-resolved spectrum obtained.This research is helpful for understanding the properties and validating the mechanism of n-dodecane combustion reaction.
Using a heated shock tube and an intensified spectroscopic detector CCD,transient emission spectra of n-dodecane in the combustion reaction were measured in the range of 200~900 nm.Experiments were conducted at pressure of 4.0atm,temperatures of(1 200~1 300)K,equivalence ratios of 0.5,1.0,and 2.0.Results show that the main emission bands are attributed to OH,CH and C2 radicals produced during the combustion process.In the different equivalence ratios,the emission intensities of OH(306.4 nm)/CH(431.4 nm)/C2(516.4 nm)are significantly different in the combustion process,which indicates that fuel-lean situation is good for generation of OH radicals,and fuel-rich situation is good for C2.Different diluent gases lead to different combustion temperatures when the fuel burns,which causes the different patterns of the emission spectra of the fuel.The variation of OH,CH and C2 radicals produced in the combustion of n-dodecane are shown clearly by the time-resolved spectrum obtained.This research is helpful for understanding the properties and validating the mechanism of n-dodecane combustion reaction.
引文
[1]HUMER S,FRASSOLDATI A,GRANATA S,et al.Experimental and kinetic modeling study of combustion of JP-8,its surrogates and reference components in laminar nonpremixed flows[J].Proceedings of the Combustion Institute,2007,31(1):393-400.
[2]MONTGOMERY C J,CANNON S M,MAWID M A,et al.Reduced chemical kinetic mechanisms for JP-8 combustion[R].AIAA,2002,2002-0336.
[3]WANG H,DAMES E,SIRJEAN B,et al.JetSurF version 2.0,a high-temperature chemical kinetic model of n-alkane(up to n-dodecane),cyclohexane,and methyl-,ethyl-,n-propyl and n-butyl-cyclohexane oxidation at high temperatures,September 19,2010(http://melchior.usc.edu/JetSurF/JetSurF2.0).
[4]WESTBROOK C K,PITZ W J,HERBINET O,et al.A comprehensive detailed chemical kinetic reaction mechanism for combustion of n-alkane hydrocarbons from n-octane to nhexadecane[J].Combustion and Flame,2009,156(1):181-199.
[5]WANG H,YOU X Q,JOSHI A V,et al.USC mech version ii,high-temperature combustion reaction model of H2/CO/C1-C4compounds,May,2007(http://ignis.usc.edu/USC_Mech_II.htm).
[6]WANG Q D,WANG J B,LI J Q,et al.Reactive molecular dynamics simulation and chemical kinetic modeling of pyrolysis and combustion of n-dodecane[J].Combustion and Flame,2011,158(2):217-226.
[7]FANG Ya-mei,WANG Quan-de,WANG Fan,et al.Reduction of the detailed kinetic mechanism for hightemperature combustion of n-dodecane[J].Acta PhysicoChimica Sinica,2012,28(11):2536-2542.方亚梅,王全德,王繁,等.正十二烷高温燃烧详细化学动力学机理的系统简化[J].物理化学学报,2012,28(11):2536-2542.
[8]VASU S S,DAVIDSON D F,HONG Z,et al.n-Dodecane oxidation at high-pressures:Measurements of ignition delay times and OH concentration time-histories[J].Proceedings of the Combustion Institute,2009,32(1):173-180.
[9]MALEWICKI T,BREZINSKY K.Experimental and modeling study on the pyrolysis and oxidation of n-decane and n-dodecane[J].Proceedings of the Combustion Institute,2013,34(1):361-368.
[10]HAYLETT D R,DAVIDSON D F,HANSON R K.Ignition delay times of low-vapor-pressure fuels measured using an aerosol shock tube[J].Combustion and Flame,2012,159(2):552-561.
[11]HERBINET O,MARQUAIRE P M,FOURNRT R,et al.Thermal decomposition of n-dodecane:Experiments and kinetic modeling[J].Journal of Analytical and Applied Pyrolysis,2007,78(2):419-429.
[12]KURMAN M S,NATELSON R H,CERNANSKY N P,et al.Speciation of the reaction intermediates from n-dodecane oxidation in the low temperature regime[J].Proceedings of the Combustion Institute,2011,33(1):159-166.
[13]COOKEA J A,BELLUCCIA M,SMOOKEA M D,et al.Computational and experimental study of JP-8,a surrogate,and its components in counterflow diffusion flames[J].Proceedings of the Combustion Institute,2005,30(1):439-446.
[14]KUMAR K,SUNG C J.Laminar flame speeds and extinction limits of preheated n-decane/O2/N2and ndodecane/O2/N2mixtures[J].Combustion and Flame,2007,151(1-2):209-224.
[15]ZHANG Chang-hua,TANG Hong-chang,ZHANG Chuanzhao,et al.Diagnosis of iso-octane combustion in a shock tube by emission spectroscopy[J].Chemical Physics Letters,2013,556:13-17.
[16]LAMOUREUX N,DESGROUX P,BAKALI A E,et al.Experimental and numerical study of the role of NCN in prompt-NO formationin low-pressure CH4-O2-N2and C2H2-O2-N2flames[J].Combustion and Flame,2010,157(10):1929-1941.
[17]BROWN D M,SANDVIK P M,FEDISON J B,et al.Determination of lean burn combustion temperature using ultraviolet emission[J].IEEE Sensors Journal,2008,8(3-4):255-260.
[18]KOPP M,BROWER M,MATHIEU O,et al.CO2chemiluminescence study at low and elevated pressures[J].Applied Physics B,2012,107(3):529-538.
[2]MONTGOMERY C J,CANNON S M,MAWID M A,et al.Reduced chemical kinetic mechanisms for JP-8 combustion[R].AIAA,2002,2002-0336.
[3]WANG H,DAMES E,SIRJEAN B,et al.JetSurF version 2.0,a high-temperature chemical kinetic model of n-alkane(up to n-dodecane),cyclohexane,and methyl-,ethyl-,n-propyl and n-butyl-cyclohexane oxidation at high temperatures,September 19,2010(http://melchior.usc.edu/JetSurF/JetSurF2.0).
[4]WESTBROOK C K,PITZ W J,HERBINET O,et al.A comprehensive detailed chemical kinetic reaction mechanism for combustion of n-alkane hydrocarbons from n-octane to nhexadecane[J].Combustion and Flame,2009,156(1):181-199.
[5]WANG H,YOU X Q,JOSHI A V,et al.USC mech version ii,high-temperature combustion reaction model of H2/CO/C1-C4compounds,May,2007(http://ignis.usc.edu/USC_Mech_II.htm).
[6]WANG Q D,WANG J B,LI J Q,et al.Reactive molecular dynamics simulation and chemical kinetic modeling of pyrolysis and combustion of n-dodecane[J].Combustion and Flame,2011,158(2):217-226.
[7]FANG Ya-mei,WANG Quan-de,WANG Fan,et al.Reduction of the detailed kinetic mechanism for hightemperature combustion of n-dodecane[J].Acta PhysicoChimica Sinica,2012,28(11):2536-2542.方亚梅,王全德,王繁,等.正十二烷高温燃烧详细化学动力学机理的系统简化[J].物理化学学报,2012,28(11):2536-2542.
[8]VASU S S,DAVIDSON D F,HONG Z,et al.n-Dodecane oxidation at high-pressures:Measurements of ignition delay times and OH concentration time-histories[J].Proceedings of the Combustion Institute,2009,32(1):173-180.
[9]MALEWICKI T,BREZINSKY K.Experimental and modeling study on the pyrolysis and oxidation of n-decane and n-dodecane[J].Proceedings of the Combustion Institute,2013,34(1):361-368.
[10]HAYLETT D R,DAVIDSON D F,HANSON R K.Ignition delay times of low-vapor-pressure fuels measured using an aerosol shock tube[J].Combustion and Flame,2012,159(2):552-561.
[11]HERBINET O,MARQUAIRE P M,FOURNRT R,et al.Thermal decomposition of n-dodecane:Experiments and kinetic modeling[J].Journal of Analytical and Applied Pyrolysis,2007,78(2):419-429.
[12]KURMAN M S,NATELSON R H,CERNANSKY N P,et al.Speciation of the reaction intermediates from n-dodecane oxidation in the low temperature regime[J].Proceedings of the Combustion Institute,2011,33(1):159-166.
[13]COOKEA J A,BELLUCCIA M,SMOOKEA M D,et al.Computational and experimental study of JP-8,a surrogate,and its components in counterflow diffusion flames[J].Proceedings of the Combustion Institute,2005,30(1):439-446.
[14]KUMAR K,SUNG C J.Laminar flame speeds and extinction limits of preheated n-decane/O2/N2and ndodecane/O2/N2mixtures[J].Combustion and Flame,2007,151(1-2):209-224.
[15]ZHANG Chang-hua,TANG Hong-chang,ZHANG Chuanzhao,et al.Diagnosis of iso-octane combustion in a shock tube by emission spectroscopy[J].Chemical Physics Letters,2013,556:13-17.
[16]LAMOUREUX N,DESGROUX P,BAKALI A E,et al.Experimental and numerical study of the role of NCN in prompt-NO formationin low-pressure CH4-O2-N2and C2H2-O2-N2flames[J].Combustion and Flame,2010,157(10):1929-1941.
[17]BROWN D M,SANDVIK P M,FEDISON J B,et al.Determination of lean burn combustion temperature using ultraviolet emission[J].IEEE Sensors Journal,2008,8(3-4):255-260.
[18]KOPP M,BROWER M,MATHIEU O,et al.CO2chemiluminescence study at low and elevated pressures[J].Applied Physics B,2012,107(3):529-538.