A Study of NOx Formation Characteristics in CH4-Air Jet Diffusion Flame

초록

Numerical anaysis was performed with multicomponent transport properties and detailed reactin mechanisms for axisymetric 2-D CH4 jet diffusion flame. Calculations were carried out twice with the C2-Thermal mechanism including C2 and Thermal NO reactions and the C2-Full mechanism including prompt NO reactions in addition to the above C2-Thermal NO mechanism. The results show that the flame structures such as flame temperature, major and minor species concentration are indifferent to respective mechanisms. The production path of Thermal NO is dominant comparing with that of Prompt NO in total NO production of pure CH4 jet diffusion flame. This is because thermal NO mechanism mainly contributes to positive formation of NO in the whole flame region, but Prompt NO mechanism contributes to negative formation in the fuel rich region. In addition, O2 penetration near the nozzle outlet affects the flame structures, especially NO2 formation characteristics.