基于Damk(o)hler数的氢气层流扩散火焰抑制模拟研究

摘要

通过对未添加及添加1%的Br2对氢气同向流扩散火焰的影响进行数值模拟,研究抑制剂对氢气层流扩散火焰温度及主要自由基的影响,并通过计算两种火焰的化学特征时间及混合特征时间得到Damk(o)hler数,提出基于抑制剂的标量耗散率,研究抑制剂的扩散作用及化学作用对氢气同向流扩散火焰的影响.研究发现抑制剂的火焰抑制循环使火焰中化学作用增强,而抑制剂的扩散作用对火焰整体的扩散作用有较显著的影响.添加抑制剂后在径向大部分区域火焰的Da数均低于未添加情况下,抑制剂减少火焰燃烧区域,并使燃烧区域的反应剧烈程度下降.从火焰根部到火焰顶端,抑制作用逐渐减弱.%A numerical study on hydrogen-air co-flow non-premixed flames with and without inhibitor was carried out to investigate the effects of Br2 on the flame temperature,the main radicals,characteristic chemical time as well as characteristic diffusion time.We calculated the Damk(o)hler number and the inhibitor-based scalar dissipation rate to study the physical and chemical effects on hydrogen-air co-flow non-premixed flames.The result shows that the flame inhibition cycle enhanced the chemical process of the flame,while the inhibitor-based scalar dissipation rate had a significant impact on the overall scalar dissipation rate.In most radial zone of the flame Da number was lower than the case of undoped flame,and the inhibitor reduced the flame region and decreased the intensity of the combustion reaction zone.The inhibition effect gradually decreased with the increase of the flame height.