CH4/Air-CO2 대향류 확산화염의 NOx 생성 특성 및 화염구조

초록

Numerical study with detailed chemistry has been conducted to investigate the NOx formation and structure in CH4/Air-CO2 counterflow diffusion flames. The importance of radiation effect is identified and the role of CO2 addition is addressed to thermal and chemical reaction effects, which can be precisely specified through the introduction of an imaginary species. Also NO separation technique is utilized to distinguish the contribution of thermal and prompt NO formation mechanisms. The results are as follows : The radiation effect is dominant at low strain rates and it is intensified by CO2 addition. Thermal effect mainly contributes to the changes in flame structure and the amount of NO formation but the chemical reaction effect also cannot be neglected. It is noted that flame structure is changed considerably due to the addition of CO2 in such a manner that the path of methane oxidation prefers to take CH4→CH3→C2H6→C2H5 instead of CH4→CH3→CH2→CH. At low strain rate(a=10) the reduction of thermal NO is dominant with respect to reduction rate, but that of prompt NO is dominant with respect to total amount.