含水乙醇燃烧的对冲扩散火焰数值研究

摘要

为加深对低浓度乙醇燃气发生器燃烧过程化学动力学过程的理解,分析水组分在燃烧过程中所起的作用,利用对冲扩散火焰模型对不同浓度下的火焰结构进行了数值分析,并虚拟了一种惰性水组分以区分物理机制和化学机制对燃烧过程产生的影响.研究结果显示,随着乙醇浓度的不断降低,火焰锋面呈现出向燃料侧的整体移动趋势;随着浓度向极限浓度的趋近,化学动力学特征表现为二次释热区的消失;水组分的化学机制将在低浓度极限下发挥作用,并表现出对反应过程的抑制作用.%Hie counteiflow diffusion combustion of diluted ethanol in various containments was numerically analyzed in the purpose of getting a deep understanding of chemdynamics in a gas generator with low ethanol concentration. A virtual specie with the same thermodynanric and transport property as water but chemically inert was used to distinguish the interference between physical and chemical mechanism. Results reveal that as the concentration of ethanol decrease, the flame front, along with the disappearance of the second exothermic reaction region, tends towards the fuel side as a whole. The H2O will exert an inhibitory effect when the concentration of ethanol is reduced to the ultimate low value.