Lean flame conditions have been used in Combustion Processes and Gas Turbines during the last few years for the reduction of emissions and for their high stability. However, there are problems related to flashback towards the premixing chambers when highly hydrogen enriched blends are used, a problem that occurs when syngas and/or biofuels are used. For this reason, this paper describes an experimental process for data acquisition under different geometries of a swirl burner in order tocharacterize the phenomenon, which was visualized using High Speed Photography. The study was based on the external and internal
analysis of the burner. The use of a central combustible injector demonstrated to be beneficial for flashback reduction due to the suppression of some coherent structures. Nevertheless, the
presence of the former can cause damaging explosions in the system if the flashback point is reached.