Experimental study of the influence of the swirl number on lean premixed combustion regimes

Lean premixed turbulent swirling combustion is known for significantly reducing pollutants emissions, when compared to non-premixed turbulent flames. Characterizing the swirl number influence is therefore essential to comparing different combustion chamber operational regimes. The present study is devoted to the experimental characterization of a new family of swirlers currently being developed. The associated combustion process is found to exhibit different flame topologies, or combustion regimes, which are functions of the mixture equivalence ratio and flow rate. The flame topologies and the boundaries between the observed combustion regimes are evidenced by means of OH* chemiluminescence and overall flame chemiluminescence.