Observations on the interaction between a premixed flame kernel and a vortex of different equivalence ratio

The interaction between a lean premixed spark-ignited flame kernel and a laminar vortex toroid containing a different fuel/air mixture was experimentally studied to gain an understanding of the effect of "turbulent" bulk transport of material into the growing flame kernel. Flame kernels were ignited in a lean premixed methane/air mixture with equivalence ratio of 0.6:1, while the equivalence ratio of the vortex core fluid was varied between zero and infinity. Results of the flame kernel-vortex interactions for six test cases were presented and elucidated. Vortices composed of fluid outside the traditional flammability limits were completely consumed inside the growing flame kernel. Due to entrainment of ambient fluid as the vortex propagated towards, the kernel the equivalence ratio of the vortex was not constant. The Lewis number of the vortex mixture determined if the vortex was consumed as a single pocket or broke up into multiple pockets before being consumed. Pure fuel vortices had a very diffuse reaction zone as well as a region at the upper rim of the kernel-vortex interface of intense chemiluminescence. Original is an abstract.