Influence of CO addition on the flame structure and temperature of a micro-jet methane diffusion flame

Although the micro-jet flame has received a lot of attention, there is a lack of studies on the influence of the composition variation of the CO/methane blended fuels. The present work reveals the impact of CO addition on the combustion characteristics of the micro-jet methane flame so as to improve the combustion stability for the practical utilization of the MEMS (Micro Electro Mechanical System). It is found that the flame height decreases with the increase of CO, which means that the increase of flame height with the increased inlet velocity can be inhibited by the addition of CO. The flame structures are similar for different CO addition fraction. Interestingly, the flame temperature increases first and then decreases with the increased CO because the present flame temperature is mainly determined by the physical effect of CO addition on the chemical reaction. The addition of CO also affects the flame-wall thermal interaction. Due to the competitive relationship between the flame position and temperature, the heat loss of the flame through the wall will increase first and then decrease with the increase of CO. Similarly, the preheating heat of fresh fuel also shows the similar trend with the heat loss and the preheating temperature of the new fuel reaches the highest in the case of 10%CO-90%CH4. All in all, the addition of CO can significantly affect the position, temperature, and behavior of the micro-jet flame.