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.

This content is only available via PDF.
You do not currently have access to this content.