Interaction of a lean premixed flame-kernel and laminar vortex with different mixture ratios

Charge stratification by direct local injection is currently being studied as a potential technology for application in spark ignited lean burn engines. Local mixture enrichment by direct injection in the vicinity of the spark plug at the time of ignition can dramatically affect flame kernel development and extend the lean flammability limit of the remaining homogeneous fuel/air mixture. Flame-vortex interactions have been used over the past decade to gain understanding of the chemistry-turbulence interaction. Experiments were conducted on interactions between a lean premixed, spark-ignited flame kernel and a laminar vortex composed of fluid with a different fuel/air mixture to study the fundamental role of chemistry-turbulence interactions on the ignition of a model stratified flow. Specifically, flame kernels were ignited in a homogeneous lean (φ = 0.6) CH4/air mixture while the vortex core fluid contained CH4/air mixtures at six different equivalence ratios, ranging from 0 to infinity. Chemiluminescence images of kernel-vortex interactions were captured using either a single shot ICCD camera or a high-speed intensified camera. Details about these six different flame kernel-vortex interaction test cases are presented and discussed.