Flashback Propensity in Swirl Stabilized Burner With Syngas Fuels Available to Purchase

In swirl stabilized burner, combustion induced vortex breakdown (CIVB) flashback is a significant phenomenon. This paper presents experimental measurements of CIVB flashback propensity for hydrogen (H₂)-carbon monoxide (CO) flames. The effects of H₂ concentration, and swirl number on the flashback propensity of H₂-CO flames are discussed. For a given air mass flow rate, the stoichiometric ratio (%F) at which the CIVB flashback occurs decreases with the increase in H₂ concentration in fuel mixtures. However it appears that near the CIVB flashback limit, the swirl strength plays a more dominating role over the H₂ concentration in the fuel mixture. The flashback propensity decreases with the increase in swirl number. An analysis of the nonreacting flow field (Air 6 g/s) as well as reacting (CH₄-Air and H₂-CO-Air) flame near the CIVB transient velocity field was conducted. The analysis revealed that a complex vortex-chemistry interaction leading to vortex breakdown and flashback occurred. The vector flow field showed that the high swirling flow generates a more stabilized and wider recirculation zone. It also showed that the presence of H₂ dictates the intensity of the flashback process.