甲烷微尺度燃烧中气相反应与催化反应间的相互作用

Interactions between gas-phase reaction and catalytic reaction in methane microscale combustion

以往对甲烷微尺度催化燃烧的研究中,甲烷的气相反应往往没有受到足够的重视,有时候甚至被忽略。为了了解气相反应在甲烷的微尺度燃烧中所起的作用,本文使用了计算流体力学软件Fluent对CH_4和空气的预混气体在微尺度平板燃烧器中的催化燃烧过程进行了数值模拟,对比在0.2mm和1mm两种间距的微尺度平板燃烧器内CH_4的催化燃烧过程,研究了微尺度平板燃烧器内CH_4气相反应与CH_4催化反应的相互影响,其中重点研究了CH_4气相反应对CH_4催化反应的影响。模拟结果显示:(1)在间距为0.2mm和1mm的微尺度平板燃烧器中,CH_4气相反应均是由CH_4催化反应所引起;(2)在0.2mm间距的微尺度平板燃烧器中,CH_4气相反应产生的OH促进了CH_4催化反应的进行;(3)在1mm间距的微尺度平板燃烧器中,CH_4气相反应对CH_4催化反应仍然具有促进作用,但对CH_4催化反应的抑制作用更为显著。研究结果可以为设计和开发高效稳定的微尺度平板燃烧器提供参考。

In previous studies of CH4 microscale catalytic combustion, CH4 gas-phase reaction usually was not paid enough attention and even was ignored sometimes. To know the role of CH4 gas-phase reaction playing in CH4 microscale catalytic combustion, a simulation of CH4/air premixed gas catalytic combustion in microscale parallel plate combustor was done in computational fluid dynamics software. CH4 catalytic combustion inmicro scale parallel plate combustors of 0.2mm and lmm distance were compared. The interactions between CH4 gas-phase reaction and CH4 catalytic reaction were investigated, and the effect of CH4 gas-phase reaction on CH4 catalytic reaction was investigated particularly. Several regularities were revealed by simulation results. First, CH4 gas-phase reaction was caused by CH4 catalytic reaction in microscale parallel plate combustors of 0.2mm and 1ram distance. Second, in microscale parallel plate combustor of 0.2mm distance, OH produced from CH4 gas-phase reaction promoted CH4 catalytic reaction. Third, in microscale parallel plate combustor of lmm distance, CH4 gas-phase reaction still had positive effect on CH4 catalytic reaction, but its negative effect was more remarkable. The results can be used to provide reference to the development of efficient and stable microscale parallel plate combustor.