AC等离子体辅助CH4低温氧化的分子激发作用

本文采用实验测量和数值模拟结合的方法,对AC放电下He/CH4/O2混合气中激发态对甲烷裂解和低温氧化的动力学贡献进行研究。基于HP-Mech,增加反应物的放电机理以及激发态参与的化学反应及其驰豫反应,建立CH4低温氧化机理。采用化学反应动力学求解器CHEMKIN中的两段式Plasma-PSR模型模拟放电过程及化学反应过程。该动力学模型能较好地预测反应物的消耗和主要产物的生成,反应路径分析表明激发态物质CH4(v),O2(v),O2(a^1△g)等通过链式反应CH4(v)+OH→CH3+H2O,O2(v)+H→OH+O,O2(a^1△g)+H→OH+O促进活性自由基和产物的生成。

Kinetic Effects of Excited States on AC Plasma Assisted Methane Low Temperature Oxidation

Methane pyrolysis and oxidation by excited states in AC discharges was studied in He/CH4/O2 mixtures by methods of experimental measurements and numerical simulations.Based on the comprehensive HP-Mech,a plasma assisted CH4 low temperature oxidation kinetic mechanism incorporating the electron impact reactions and reactions involving excited species was developed.The two-stage Plasma-PSR module in the chemical kinetics solver CHEMKIN was used to simulate the plasma discharge process and the chemistry reaction process.Numerical comparisons with steady state measurements showed a significant agreement for consumption of reactants and formation of main products.Analysis of reaction pathways indicates that excited species CH4(v),O2(v),O2(a^1△g)enhance chain propagating reactions CH4(v)+OH→CH3+H2 O,O2(v)+H→OH+O,O2(a^1△g)+H→OH+O,thus stimulating the production of active radicals and final products.