Combustion characteristics of syngas laminar microjet diffusion flames

Abstract

Two-dimensional numerical investigations of laminar microjet syngas (H2 - CO) diffusion flames are carried out in the present study. A detailed parametric study on the effects of fuel jet velocity and fuel composition on global flame characteristics is analyzed. Results show that the flame height increases with an increase in fuel jet velocity, and it decreases with an increase in hydrogen content in the fuel mixture. The dependence of fuel composition and jet velocity on the rate of tube wall heat recirculation is explored. The radial extent of flame increases with increase in hydrogen content in the fuel mixture. The analysis of key reactions in the standoff region revealed the significant contribution of HO2 radical in the formation of high-temperature reaction zone. Flame extinction is observed at lower fuel jet velocities, as the composition of hydrogen in fuel mixture increases from 10 to 90%. Near extinction, the combined effect of axial and radial diffusion results in the formation of spherically shaped flames.