催化燃烧中表面反应-气相反应间相互作用及其对均质压燃发动机着火特性的影响

Interactions between surface reactions and gas phase reactions in catalytic combustion and their influence on ignition of HCCI engine

通过对微元管中甲烷在铂表面的催化燃烧过程的数值计算,分析了当混合气入口压力很高时气相反应对整个催化燃烧过程的影响;通过敏感度分析,找出了对异相着火及气相着火起主要作用的基元反应步.结果表明,在异相着火过程中起主要作用的基元反应步为甲烷与氧气在催化剂表面的吸附反应及氧气的解吸反应,在气相着火过程中起主要作用的基元反应步为OH·及水的吸附与解吸反应.对活塞顶涂有铂催化剂的均质压燃(HCCI)发动机的燃烧过程进行了数值模拟,分析了催化效应及关键表面反应基元步对HCCI发动机着火时刻以及燃烧过程中中间组分的影响,结果表明,催化反应能促进混合气的着火,缩短着火延迟时间,对HCCI发动机着火时刻起主要影响的表面反应为OH·及水的吸附与解吸反应.

The catalytic combustion of methane in a micro-channel whose surface was coated with platinum catalyst was studied by numerical simulation. The effects of gas phase reaction on the whole catalytic combustion process were analyzed at a high inlet pressure. A sensitivity analysis of the surface reactions mechanisms of methane corn the heterogeneous ignition sensitive reactions affecting bustion on platinum catalyst revealed that the most sensitive reactions affecting were oxygen adsorption/desorption and methane adsorption, and the most the gas ignition were OH · and H20 adsorption/desorption. The combustion process of the homogeneous charge compression ignition （HCCI） engine with Pt-coated pist simulated. The effects of catalysis and the most sensitive reactions on the ignition timi concentration of intermediate species during the HCCI engine combustion were discussed. on ng Th face and was the e results showed that catalytic combustion could advance the ignition timing, and the most sensitive reactions affecting the ignition timing of the HCCI engine were OH ·and H2O adsorption/desorption.