正庚烷低压预混燃烧火焰中间产物生成特性分析.pdf

机械设计与制造
第3期
262
Machinery Design Manufacture
2014年3月
正庚烷低压预混燃烧火焰中间产物生成特性分析
秦先锋,袁银男2,李仁春,李立琳1
(1.江苏大学汽车与交通工程学院,江苏镇江212013
2.南通大学机械工程学院,江苏南通226019)
摘要:采用数值模拟的方法研究正庚烷低压预混层流燃烧火焔,分析了正庚烷化学反应路径及燃娆产物,考察了OH,
0,H自由基的摩尔分数变化,比較了火焰中同类烷烃、烯烃和炔烃摩尔分数,通过C2H4的敏感性分析探讨了燃烧火焰中
烯烃生成和消耗路径。结果表明:随火焰高度的増加,H20、CO和CO2摩尔分数増大,火焰高度1.3cm以后,CO的摩尔分
数开始下降,对应的CO2摩尔分数迅速增加。OH,0,H自由基摩尔分数的最大量级为104~10,OH,0,H自由基摩尔分数
的迅速增大反映燃烧中间产物的消耗反应较剧烈。正庚烷燃火姳烯烃生成较多,C2媂烃摩尔分数的峰值分别是同类烷
烃和烯烃的32、85倍,C3烯烃的摩尔分数的峰值是同类炔烃7,2倍
关键词:正庚烷;预混燃烧;中间产物;自由基
中图分类号:TH16;TK401文献标识码:A文章编号:1001-3997(2014)03-0262-03
Combustion Intermediate Radical Characteristics of N-heptane in
a Low-pressure Premixed Laminar Flame
QIN Xian-feng, YUAN Yin-nan,, LI Ren-chun, II Li-lin
(1. School of Automobile and Traffic Enginecring, Jiangsu University, Jiangsu Zhenjiang 212013, China;
2. School of Mechanical Engineering, Nantong University, Jiangsu Nantong 226019, China
Abstract: A numerical study on low-pressure premixed N-heptare laminar flame was conducted. his work focused on both the
chemical reaction path and the combustion intermediate. Therefore, mole fraction wariation of OH, 0, and H radicals were
analyzed, and the resultants of similar olefins, alkanes, and ak nes in the Mlme oere compared The numeric result shoed
that with the increase offame height, H 0, CO and O mole fraction increased, fier the flame height 1.3cm, CO mole fraction
began to decrease, correspondingly CO mole fraction increased rapidly, and CO was oxidized to CO The maimum magnitude
of the mole fraction of Of, O, and H radicals were 10-10. The rapid increase reflected that the reaction of combustion
intermediate consumption was severe. he comparison of resultants revealed that generation of olefins in low-pressure
premixed N heptane Laminar fame were more than other resultants, which the peak of mole fraction of C2 Olefin are
respectively 32 and 85 times more than similar alkanes and olefins, likewise, 7.2 times much more than the same kinds of
alkynes compared to Cy Olefin.
Key Words: N-heptane; Premixed Combustion; Intermediate Products; Radicals
1引言
的影响。文献研究了包括正庚烷在内的C1-C2烷烃的热解,比较
正庚烷和柴油的十六烷值非常接近,在化学反应动力学机
了支链、不饱和度、取代基等因素对烷烃热解产物分布的影响。
理模拟硏究上,可以作为柴油的代替燃料,其燃烧及排放污染物
依照文献的机理,采用低压预混燃烧模型,对正庚烷低压
的形成路径及燃烧中闾过程受到国内外学者广泛的关注。文献
预混火焰燃烧下中间自由基的生成特性进行数值模拟;分析正庚
利用激波管测量了(16~2.0)atm压力范围、(1100~150)K温度范烷裂解路线,并对影响多环芳香烃前驱体乙烯进行了敏感性分
围,正庚烷热解中甲基浓度随时问的变化趋势,认为甲基生成速析。
率是正庚烷热解反应速率的关键步骤。文献利用射流搅拌反应2计算结果与分析
器开展了一系列正庚烷的氧化实验,其中包括正庚烷、正庚烷混
设定进气质量流量为35x10gs-cm2;初始压力为0.522atm,
合异辛烷、正庚烷添加生物柴油、正庚烷添加乙醇等燃料的氧化初始网格数6.0,网格自适应系数为0.2,以氮气作为稀释气体,过
反应,研究在正庚烷中添加不同的生物质燃料对正庚烷氧化反应量空气系数p=1,以此模拟正庚烷在低压预混火焰燃烧时的化学
来稿日期:2013-08-10
基金项目:国家自然科学基金(No5076042);江苏省高校自然科学基金重点项目(No、08KJA47000
作者简介:秦先锋,(1976-),男,河南周口人,硕土研究生,主要研究方向:发动机燃料燃烧的研究
袁银南,(1959-),男,江苏常熟人,教授,博士生导师,主要研究方向:内燃机工作过程和代用燃料