同轴管甲烷逆流燃烧器中火焰结构与燃烧稳定性

doi:10.11949/j.issn.0438-1157.20151926

摘要/Abstract

摘要：

用骨架反应机理对同轴管甲烷逆流燃烧器进行分析能够很好地了解火焰结构与燃烧器内的温度分布，并得到各处的火焰拉伸率及相关参数。随着空气流量（Q_A）的增加，火焰形状由扁平型变化为弯曲型，并逐渐将内管管口包覆，火焰厚度逐渐减小。当量比（ER）较大时，火焰附近温度与物质的分布较为稀疏，而ER较小时，其分布较为紧密。内管壁面上热通量H_f随着的Q_A增加而逐渐加强；总的传热量H在Q_A=2540 ml·min^-1达到最大。当ER≥3.00时，火焰拉伸率κ开始时缓慢变化，在越过燃烧器内管边缘后快速增加，但最终不大于65 s^-1。在ER<1.00时，火焰呈弯曲状，长度较长，κ值变化剧烈，最大可以达到638 s^-1，并在火焰末端κ值变为负数，最小值为-262 s^-1。

关键词: 甲烷, 数值模拟, 传热, 逆流, 燃烧状态, 火焰拉伸率

Abstract:

By using the skeletal reaction mechanism, the combustion in an opposed methane jet in coaxial narrow air stream tubes is studied. The temperature, species distribution, heat flux, flame stretch rate and flame curvature are calculated. When the fuel flow rate (Q_F)=120 ml·min^-1, with increasing Q_A, the flame changes from flat-disk shape to curved one and covers the inner tube exit, and the flame is forced to move toward the exit of inner pipe. The flame is compressed and the distributions of temperature and species are compact. When equivalence ratio (ER)>1.00, with increasing Q_A, the peak temperature and the flame length along the flame surface rise and reach the maximum, while when ER≤1.00, the peak temperature and the flame length decrease. The after burning gas preheats the inlet methane through the inner pipe and the total heat flux is influenced by the flame temperature and gas flow. With the increase of Q_A, the heat flux is much stronger and the preheating increases, reaching the maximum when Q_A=2450 ml·min^-1. When Q_A>2450 ml·min^-1, the preheating goes down. When ER>1.00, the stretch rate of flame κ is small and changes slowly at the beginning, and then it rises sharply along the flame surface but finally it is no more than 65 s^-1. When ER≤1.00, along the flame surface, κ increases first and then decreases, and finally become negative with the minimum value of -262 s^-1. The increase of Q_A makes κ change seriously. The maximum of κ is 638 s^-1.

Key words: methane, numerical simulation, heat transfer, opposed flow, combustion characteristics, flame stretch

中图分类号:

TK16

黄景怀, 李军伟, 陈新建, 魏志军, 王宁飞. 同轴管甲烷逆流燃烧器中火焰结构与燃烧稳定性[J]. 化工学报, 2016, 67(9): 3590-3597.

HUANG Jinghuai, LI Junwei, CHEN Xinjian, WEI Zhijun, WANG Ningfei. Flame stability and structure of opposed methane/air jet in coaxial tubes[J]. CIESC Journal, 2016, 67(9): 3590-3597.

参考文献 35

[1]	张冬至, 胡国清. 微机电系统关键技术及其研究进展[J]. 压电与声光, 2010, 32(3):513-520. ZHANG D Z, HU G Q. Key technologies of micro-electromechanical system and its recent progress[J]. Piezoelectrics & Acoustooptics, 2010, 32(3):513-520.
[2]	陈勇华. 微机电系统的研究与展望[J]. 电子机械工程, 2011, 27(3):1-7. CHEN Y H. Development and prospect of micro-electromechanical system[J]. Electro-Mechanical Engineering, 2011, 27(3):1-7.
[3]	李军予, 伍保峰, 张晓敏. 立方体纳卫星的发展及其启示[J]. 航天器工程, 2012, 21(3):80-87. LI J Y, WU B F, ZHANG X M. Development of cubesat and its enlightenment[J]. Spacecraft Engineering, 2012, 21(3):80-87.
[4]	DUNN-RANKIN D, LEAL E M, WALTHER D C. Personal power system[J]. Prog. Energy Combust. Sci., 2005, 31(5/6):422-465.
[5]	MARUTA K, TAKEDA K, SITZKI L, et al. Catalytic combustion in micro-channel for MEMS power generation[C]//The Third Asia-Pacific Conference on Combustion. Seoul, Korea, 2001:1-4.
[6]	陈光文, 赵玉潮, 乐军, 等. 微化工过程中的传递现象[J]. 化工学报, 2013, 64(1):63-75. CHEN G W, ZHAO Y C, YUE J, et al. Transport phenomena in micro-chemical engineering[J]. CIESC Journal, 2013, 64(1):63-75.
[7]	FERNANDEZ-PELLO A C. Micro-power generation using combustion:issues and approaches[J]. Proc. Combust. Inst., 2002, 29(1):883-899.
[8]	SIRIGNANO W A, PHAM T K, DUNN-RANKIN D. Miniature-scale liquid-fuel-film combustor[J]. Proc. Combust. Inst., 2002, 29(1):925-931.
[9]	ZAMASCHIKOV V V. Combustion of gases in thin-walled small diameter tubes[J]. Combust. Explos. Shock Waves, 1995, 31(1):20-22.
[10]	MARUTA K. Micro and mesoscale combustion[J]. Proc. Combust. Inst., 2011, 33(1):125-130.
[11]	WANG H O, LUO K, LU S Q, et al. Direct numerical simulation and analysis of a hydrogen/air swirling premixed flame in a micro combustor[J]. Int. J. Hydrogen Energy, 2011, 36(21):13838-13849.
[12]	BEDRA L, RUTIGLIANO M, BALAT-PICHELIN M, et al. Atomic oxygen recombination on quartz at high temperature experiments and molecular dynamics simulation[J]. Langmuir, 2006, 22(17):7208-7216.
[13]	MIESSE C M, MASEL R I, JENSEN C D, et al. Submillimeter-scale combustion[J]. AIChE Journal, 2004, 50(12):3206-3214.
[14]	MARUTA K, TAKEDA K, AHN J, et al. Extinction limits of catalytic combustion in microchannels[J]. Proc. Combust. Inst., 2002, 29(1):957-963.
[15]	KIM N I, AIZUMI S, YOKOMORI T, et al. Development and scale effects of small Swiss-roll combustors[J]. Proc. Combust. Inst., 2007, 31(2):3243-3250.
[16]	曹彬, 陈光文, 袁权. 微通道反应器内氢气催化燃烧[J]. 化工学报, 2004, 55(1):42-47. CAO B, CHEN G W, YUAN Q. Catalytic combustion of hydrogen/air in microchannel reactor[J]. Journal of Chemical Industry and Engineering(China), 2004, 55(1):42-47.
[17]	张力, 闫云飞, 李丽仙,等. 微型燃烧器内甲烷预混催化燃烧的数值研究[J]. 化工学报, 2009, 60(3):627-633. ZHANG L, YAN Y F, LI L X, et al. Numerical investigation of premixed catalytic combustion of methane in micro-combustor[J]. CIESC Journal, 2009, 60(3):627-633.
[18]	万建龙, 范爱武, 刘毅,等. 固体材料对微型钝体燃烧器吹熄极限的影响[J]. 化工学报, 2014, 65(3):1012-1017. WAN J L, FAN A W, LIU Y, et al. Effects of solid material on blow-off limit in micro bluff body combustor[J]. CIESC Journal, 2014, 65(3):1012-1017.
[19]	KIM N I, YUN Y M, LEE M J. Non-premixed flame characteristics of opposed methane jets in coaxial narrow air steam tube[J]. Int. J. Heat Fluid Flow, 2010, 31(4):680-688.
[20]	KIM N I. Numerical study of opposed non-premixed jet flames of methane in a coaxial narrow air tube[J]. Combust. Flame, 2012, 159(2):722-733.
[21]	LI J, CHOU S K, YANG W M, et al. A numerical study on premixed micro-combustion of CH4-air mixture:effects of combustor size, geometry and boundary conditions on flame temperature[J]. Chem. Eng. J., 2009, 150(1):213-222.
[22]	章熙民, 李惟毅, 李汛, 等. 高温水平圆管表面自然对流换热的研究[J]. 工程热物理学报, 1990, 11(1):56-61. ZHANG X M, LI W Y, LI X, et al. The study of heat convection on the surface of high temperature horizontal circular tube[J]. J. Eng. Thermophys., 1990, 11(1):56-61.
[23]	SERGEEV O A, SHASHKOV A G, UMANSKⅡ A S. Thermophysical properties of quartz glass[J]. J. Eng. Phys. Thermophys., 1992, 43(6):1375-1383.
[24]	SMOOKE M D. Reduced Kinetic Mechanisms and Asymptotic Approximations for Methane-air Flames[M]. Berlin:Springer-Verlag, 1991:1-28.
[25]	SESHADRI K, BAI X S, PITSCH H, et al. Asymptotic analysis of the structure of moderately rich methane-air flames[J]. Combust. Flame, 1998, 113(4):589-602.
[26]	CHEN J H, ECHEKKI T, KOLLMANN W. The mechanism of two-dimensional pocket formation in lean premixed methane-air flames with implications to turbulent combustion[J]. Combust. Flame, 1999, 116(1/2):15-48.
[27]	CLARAMUNT K, CÒNSUL R, PÉREZ-SEGARRA C D, et al. Multidimensional mathematical modeling and numerical investigation of co-flow partially premixed methane/air laminar flames[J]. Combust. Flame, 2005, 137(4):444-457.
[28]	WU C Y, CHAO Y C, CHENG T S, et al. Effects of CO addition on the characteristics of laminar premixed CH4/air opposed-jet flames[J]. Combust. Flame, 2009, 156(2):362-373.
[29]	VOSS S, MENDES M A A, PEREIRA J M C, et al. Investigation on the thermal flame thickness for lean premixed combustion of low calorific H2/CO mixtures within porous inert media[J]. Proc. Combust. Inst., 2013, 35(2):3335-3342.
[30]	PHAM T K, DUNN-RANKIN D, SIRIGNANO W A. Flame structure in small-scale liquid film combustors[J]. Proc. Combust. Inst., 2007, 31(2):3269-3275.
[31]	WAN J L, YANG W, FAN A W, et al. A numerical investigation on combustion characteristics of H2/air mixture in a micro-combustor with wall cavities[J]. Int. J. Hydrogen Energy, 2014, 39(15):8138-8146.
[32]	YOKOMORI T, MIZOMOTO M. Flame temperatures along a laminar premixed flame with a non-uniform stretch rate[J]. Combust. Flame, 2003, 135(4):489-502.
[33]	MATALON M. On flame stretch[J]. Combust. Sci. Technol., 1983, 31(3/4):169-181.
[34]	WANG P Y, WEHRMEYER J A, PITZ R W. Stretch rate of tubular premixed flames[J]. Combust. Flame, 2006, 145(1/2):401-414.
[35]	WANG J H, WEI Z L, YU S B, et al. Effect of stretch and preferential diffusion on tip opening of laminar premixed Bunsen flames of syngas/air mixtures[J]. Fuel, 2015, 148(15):1-8.