An experimental study has been carried out on a 2-dimensional turbulent lean premixed flame stabilized by a rearward facing step.
Flow visualization methods (long time exposure photograph, Schlieren & shadowgraph, and high speed Schlieren movies) were used to study the flame and its internal structure.
Effects of varying inlet velocities, inlet turbulent levels, and combustor geometries, and role of a trip wire placed above the step on the internal structure of the flame were investigated. Velocity and its fluctuation in the combustor were measured with the hot wire anemometry when there was no flame.
Flame was placed in a mixing layer, which was dominated by a large scale coherent structure. Wake behind the wire caused change in the internal structure of the blank flame and the blowout limit of the combustor. Mixing and chemical reaction were seen to be escalated by introduction of small scale eddies in the mixing layer. Flame stability is thought to be greatly dependent on entrainment of the large coherent structure in the front part of the mixing layer.
