Effect of Addition of Carbon Monoxide and Hydrogen in Syngas Inverse Diffusion Flames

This work presents a numerical study on axisymmetric inverse coflow flames fueled by synthetic gases. The simulations are carried out using ANSYS-FLUENT. The numerical model includes variable thermo-physical properties, detailed chemical kinetic mechanism, multi-component diffusion and radiation sub-model to model reactive flow. Four typical synthetic gases obtained from different gasification processes are chosen from literature. Inverse coflow burner is reported to produce lower emissions, and is chosen as the burner configuration. Characteristics of flames from inverse coflow burner are presented. Hydrogen or carbon monoxide content in the mixture is varied individually by keeping the other constituents at their average values. The power rating is chosen as 250 W. Air flow rate is also varied to study its effects on flame structure. Hydrogen and CO contents affect the formation of OH, H, heat release rate and flame stability. The maximum temperature increases with increasing hydrogen and CO. Flow, thermal and species fields are discussed in detail. Increase in hydrogen content increases the flame stability, extent of reaction zone and increases the flame temperature. The profiles of net reaction rate of several species and kinetic rate of important reactions have been discussed to explain the characteristics of these flames.