异辛烷预混层流火焰结构的数值研究

Numerical Study on Premixed Laminar Flame Structure for Iso-Octane

为解决化石燃料燃烧带来的问题,需要对燃料的基础燃烧特性进行深入研究。为此通过数值计算研究了初始压强50~101k Pa,初始温度298~353K,当量比0.6~1.5异辛烷的预混层流火焰结构特性,分析了初始压强、初始温度、当量比对火焰厚度、反应区厚度、厚度比的影响。数值计算结果表明：火焰厚度、反应区厚度、厚度比会随着初始压强和初始温度的升高而减小,随当量比的增加先减小后增大;火焰厚度、反应区厚度、厚度比分别在当量比1.1,0.9,1.3时获得最小值;层流燃烧速度与H＋OH的最大浓度有密切关系,都随初始温度的增加而增加,随初始压强的增加而减小。通过敏感性分析,发现H主要通过R3,R24,R97,R162,R163,R179生成,通过R1,R12,R14消耗;OH主要通过R1与R14生成,通过R3,R12,R16,R29,R95,R97消耗。

In order to solve the problem caused by the burning of fossil fuel,the fundamental mechanism of fuel combustion should be deeply studied. Structure characteristics of premixed laminar flame for iso-octane are studied via numerical caculation over the initial pressure range of 50~101k Pa,initial temperature range of298~353K and equivalence ratio from 0.6 to 1.5. The effects of initial pressure,temperature and equivalence ratio on flame thickness,reaction zone thickness and thickness ratio were analyzed. The calculation results show that the flame thickness,the reaction zone thickness and thickness ratio decrease with the increase of initial pressure and initial temperature. With increase of equivalence ratio,the flame thickness,the reaction zone thickness and thickness ratio increase to maximum and then decrease. The minimum of flame thickness,reaction zone thickness and thickness ratio are obtained at equivalence ratio 1.1,0.9 and 1.3. The laminar burning velocity has close relationship with the largest concentrations of H＋OH,both laminar burning velocity and the largest concentrations of H＋OH increase with increasing of initial temperature and decrease with increasing of initial pressure.Based on sensitivity analysis,H is mainly generated by R3,R24,R97,R162,R163,R179 and consumed by R1,R12,R14,while OH is mainly generated by R1,R14 and consumed by R3,R12,R16,R29,R95,R97.