Modeling of pressure effects on flame structure and soot formation of n-heptane/air co-flow laminar flames by skeletal reaction mechanism
Modeling of pressure effects on flame structure and soot formation of n-heptane/air co-flow laminar flames by skeletal reaction mechanism
复制标题
通过骨架反应机制模拟压力对正庚烷/空气同流层流火焰的火焰结构和烟灰形成的影响
DOI：
10.1016/j.applthermaleng.2016.03.006
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发表时间：
2016-08-05
影响因子：
6.4
通讯作者：
Li, Sen
中科院分区：
文献类型：
--
作者：
Li, Sen
碳氢燃料/空气的高压燃烧将化学能转化为热能，在飞机燃气轮机和柴油机中往往伴随着多环芳烃（PAHs）和碳烟的污染排放，而发动机实际湍流火焰中PAHs和碳烟形成的测量和分析是困难的。在研究中，基于正庚烷/空气的简单层流并流扩散火焰的骨架反应机制的模拟，火焰结构和碳烟形成的压力的影响进行了研究。结果表明：火焰高度在0.7 MPa（3.0 MPa）附近保持不变，火焰半径随压力p（-1/2）的增大而减小，碳烟转化率最大（eta（s，max））与压力成正比，在0.1 MPa时与2.0 MPa相似;最大碳烟体积浓度（f（v，max））随压力p（2）增加; f（v，max）和eta（s，max）沿着火焰中心线的位置不一致，f（v，max）和eta（s，max）分别出现在火焰高度的中部和下部，f（v，max）出现在混合比为0.08近似于0.09的区域和温度为1200 K左右的区域。扩散火焰由三个区域组成：燃料加热区、富燃料反应区和富氧化剂反应区。eta-C7 H16首先分解成小分子气体（例如，H-2、CH 4、C2 H2、C2 H4、C2 H6、C3 H4、C3 H6等）富燃料反应区生成多环芳烃（C6 H6、C8 H8和C10 H8）和碳烟前驱物（C2 H2、C6 H5、C6 H6和C2 H4）。(C)2016爱思唯尔有限公司版权所有
The conversion from chemical energy to thermal energy by the high-pressure combustion of hydrocarbon fuel/air is often accompanied by pollution emissions of PAHs and soot in aircraft gas turbines and diesel engines, and the measurement and analysis of PAHs and soot formations in the practical turbulent flame of engines are difficult. In the study, based on the simulation of the simple laminar co-flow diffusion flame of n-heptane/air by the developed skeletal reaction mechanism, the effects of pressure on flame structure and soot formation are investigated. The results indicate that flame height keeps constant at 0.7 similar to 3.0 MPa; the flame radius decreases with pressure as p(-1/2); the maximum carbon conversion to soot (eta(s,max)) is proportional to pressure at 0.1 similar to 2.0 MPa; the maximum soot volume concentration (f(v,max)) increases with pressure as p(2); the locations of f(v,max) and eta(s,max) along flame centerline are inconsistent, and f(v,max) and eta(s,max) occur respectively at the middle and lower parts of flame height; f(v,max) occurs in the region where the mixture fraction and temperature are respectively 0.08 similar to 0.09 and about 1200 K. The diffusion flame consists of three zones: fuel heating zone, fuel-rich reaction zone and oxidizer-rich reaction zone. eta-C7H16 is firstly decomposed into small molecule gas (e.g., H-2, CH4, C2H2,C2H4, C2H6, C3H4, C3H6, etc.) in the heating zone, and PAHs (C6H6, C8H8 and C10H8) and soot precursors (C2H2, C6H5, C6H6 and C2H4) are formed in fuel-rich reaction zone. (C) 2016 Elsevier Ltd. All rights reserved.