Interaction of adjacent flame surfaces on the formation of wrinkling laminar premixed flame

To gain further understanding of the flamelet regime of turbulent combustion, the interaction between adjacent flame surfaces of a wrinkling laminar premixed flame has been investigated experimentally. The wrinkling flame was formed with three adjacent laminar V-shaped flames stabilized ona multiple-slit burner of a propane/air mixture. In addition, a single V-shaped flame was also formed on the burner. We compared flame shapes and flow velocity distributions between those two types of flames. The results show that the unburned flow field was expanded outwardly by the convex flame surface toward unburned side. In the case of the wrinkling flame, however, the outward deviation of the flow field caused by the existence of the inner convex was prevented by the existence of the surrounding flames. Consequently, the inner convex flame surface of the wrinkling flame is more oblique, and the curvature is sharper than that of a single convex flame (single V-shaped flame) due to the interaction of adjacent flame surfaces. Moreover, the formation of the inner convex flame of the wrinkling flame is more unstable than that of a single convex flame. This is due to the curvature of the inner convex of the wrinkling flame being sharper than that of the single convex flame so that the burning velocity is decreased as a result of the curvature effect.