Abstract
The flame structure in unsteady counterflow premixed flame is investigated by numerical simulation using detailed chemical kinetics. The methane-air premixed gas and air are spouted from lower and upper planes, respectively. Fuel lean mixture (equivalence ratio is 0.75) is considered in this study. The spout velocity u_0 is varied in a sine function. The influences of average velocity u_m and frequency f in the spout velocity on flame structure are examined. The unsteady characteristics of flame structure are organized by a progress variable defined by mass fraction of oxidizer at flame front C_q and its gradient at flame front ∇C_q.
