Numerical Simulation Investigations of DRB-4Z Type Dual Channel Swirl Burner Outlet Flow Field

Abstract

Numerical simulation was used to analyze and calculate the outlet flow field of DRB-4Z type dual channel swirl burner. The results indicate that the recirculation zones become shorter, the diameter of the recirculation zones and the flow divergent angle decrease with the rising of the primary air velocity. Too lower primary air velocity causes the mixing of primary air and secondary air become weaker, which goes against the stable ignition of pulverized coal. With the increase of the outer secondary air blade angle, the flame length increases obviously. The mixing of primary air and outer secondary air is delayed, which decreases the combustion stability. Too small angle of the outer secondary air causes the generation of recirculation zone in the center of flame tail, which has adverse effect on the combustion stability. The attenuation of the highest axial velocity and tangential velocity become faster with decreasing of outer secondary air blade angle.