Effect of CO2 Dilution on Flame Structure and Soot and NO Formations in CH4-Air Nonpremixed Flames

Abstract

In the present work, a numerical analysis has been presented to show the variations in flame structure, flame radiation, and formations of soot and NO in methane-air laminar nonpremixed flames with different CO2 dilutions of fuel. It is observed that the flame length reduces as the dilution of the fuel stream by CO2 increases while maintaining constant fuel jet velocity at the burner tip. However, the flame length remains almost unchanged with different blends of CH4 and CO2 if the burner loading (i.e., fuel flow rate×heating value of fuel) is kept constant. Both soot and NO formations decrease monotonically when the CO2 fraction in the fuel is increased. The radiation from the flame also decreases when CO2 dilution of the fuel is increased, particularly, when the fuel jet velocity is maintained constant.