Flame surface density of turbulent premixed flames at medium to high turbulence intensities

Flame speed evaluations in turbulent premixed flame models often use the flamelet assumption. The principal aspect of the flamelet description for turbulent premixed flames is that the effect of turbulence is to wrinkle the flame front causing an enhancement in flame speed and local burning rate. One approach to find the local burning rate is to use the flame surface density to evaluate local burning rate. A 2-D method was used in this thesis to find the flame surface density from premixed propane/air flame front images, obtained previously on a Bunsen type burner. The results show that the integrated flame surface density and the maximum flame surface density do not show any significant variation with increasing turbulence intensity at higher turbulence intensities, which is contrary to what is expected. The assumption that flame geometry alone is responsible for flame speed enhancement for higher levels of turbulence has to be re-evaluated.