The Influence of Air Distribution on the Single-Phase Flow Field of Central Fuel Rich Swirl Burner

This paper presents a systematic study of the cold flow characteristics of a central fuel rich swirl burner. Flow fields at the burner outlet corresponding to various primary and inner secondary air ratios were measured. With decreasing primary air ratio and increasing inner secondary air ratio, the swirl intensity of the jet increases, mixing between primary and secondary air is enhanced, and the outward diffusion of the jet increases. Simultaneously the inception point of the recirculation zone moves towards the outlet of the burner. Also the zone´s maximum diameter and axial length both increase but are more strongly influenced by a changing primary air ratio rather than changing inner secondary air ratio. This influence is reversed with regard the turbulence intensity, being weaker for changing primary air ratio than changing inner secondary air ratio.