异辛烷预混层流火焰传播特性的实验与数值研究

Experimental and Numerical Study on Premixed Laminar Flame Propagation Characteristics for Iso-Octane

关键词:  异辛烷  层流火焰  预混燃烧  定容弹  传播特性

Key words:  Iso-octane  Laminar flame  Premixed combustion  Constant combustion bomb  Propagation characteristics

摘要:

利用定容弹和高速纹影摄像技术研究了初始压强50～101kPa，当量比0.8～1.3的异辛烷预混层流火焰传播特性，分析了初始压强、当量比对层流燃烧速度和马克斯坦长度的影响。实验结果表明:异辛烷层流燃烧速度随初始压强的增加而减小；在不同初始压强条件下，最大层流燃烧速度都在当量比为1.1时获得；马克斯坦长度随当量比和初始压强的增加而减小；不同初始压强条件下，当量比为1.3时，马克斯坦长度接近于0，拉伸对火焰稳定性的影响最小；简化反应机理能很好地预测富燃条件下层流燃烧速度，贫燃时略大于实验结果。

Abstract:

Propagation characteristics of premixed laminar flame for iso-octane were studied via the constant bomb and high-speed schlieren photography over the initial pressure range of 50～101 kPa and equivalence ratio from 0.8 to 1.3. The effects of initial pressure and equivalence ratio on laminar burning velocity and Markstein length were analyzed. Experimental results show that the laminar burning velocity for iso-octane decreases with the increasing of initial pressure. Under the different initial pressure condition，the maximum laminar burning velocity for iso-octane obtains at equivalence ratio 1.1. Markstein length decreases with the rising of initial pressure and equivalence ratio. When the equivalent ratio is 1.3 at different initial pressure，Markstein length is close to zero and the influence of stretch on flame stability is the minimum. The simplified reaction mechanism can predict rich fuel laminar burning velocity well. Under lean fuel condition，the results from simplified reaction mechanism are slightly larger than the experimental results.