Observation of the Distributed Reaction Zone in Turbulent Premixed Flames

Abstract

A method of observing the distributed reaction zone in turbulent premixed flames was proposed. A mixing layer between a combustible mixture and a hot burned gas, which existed in a uniform shear layer, was studied to observe the interaction between the turbulence and reaction. A typical wrinkled laminar flame appeared when the equivalence ratio of the mixture was 0.65, and for an equivalence ratio far below the flammability limit, a structure which looked like a distributed reaction zone was observed. In the latter, an intemediate reactedness and the broadening of reacting zones were predicted by the detection of fluctuating temperature, ion current and chemiluminescent emission in the zone.