高压下甲烷-正庚烷双燃料燃烧及NO生成特性

Combustion and NO Formation Characteristics of Methane/n-heptane Dual Fuel at Elevated Pressures

采用对冲火焰模型研究了压力对甲烷-正庚烷双燃料火焰结构及NO生成特性的影响。研究结果表明,该对冲火焰为三重火焰结构,具有三个放热峰。随着压力的升高,主导NO生成的路径由快速型机理变为热力型机理。压力的升高减少了CH自由基的生成,使得快速型NO排放指数随着压力的升高而减小。火焰温度随着压力的升高而增加,促进了热力型NO的生成。随着压力的升高,再燃机理对NO的消耗减缓,同时也减少了再燃机理中NO的生成。

The effects of pressure on the flame structure and NO formation in methane/n-heptane dual fuel flame were studied by using counterflow flame model.The results show that triple flame structure with three exothermic peaks is observed in the counterflow flame.With the increase of pressure,the dominant NO formation route changes from the prompt NO to the thermal NO.The increase of pressure reduces the generation of CH radical,and makes the prompt NO emission index decrease with the increase of pressure.The flame temperature increases with the increase of pressure,which promotes the formation of thermal NO.With the increase of pressure,the consumption of NO in the reburning mechanism decreases,and the formation of NO in the reburning mechanism also decreases.