Abstract

VALERA-MEDINA, A; SYRED, N  and  ABDULSADA, M. Flashback Analysis in Tangential Swirl Burners. Ing. invest. y tecnol. [online]. 2011, vol.12, n.4, pp. 487-497. ISSN 1405-7743.

Premixed lean combustion is widely used in Combustion Processes due to the benefits of good flame stability and blowoff limits coupled with low NOx emissions. However, the use of novel fuels and complex flows have increased the concern about flashback, especially for the use of syngas and highly hydrogen enriched blends. Thus, this paper describes a combined practical and numerical approach to study the phenomenon in order to reduce the effect of flashback in a pilot scale 100 kW tangential swirl burner. Natural gas is used to establish the baseline results and effects of different parameters changes. The flashback phenomenon is studied with the use of high speed photography. The use of a central fuel injector demonstrates substantial benefits in terms of flashback resistance, eliminating coherent structures that may appear in the flow channels. The critical boundary velocity gradient is used for characterization, both via the original Lewis and von Elbe formula and via analysis using CFD and investigation of boundary layer conditions in the flame front.

Keywords : swirling flows; large coherent structures; flashback.