Effects of the Flame Curvature on the Burning Velocity of Triple Flame

The upstream velocity and concentration fields of Triple Flame formed in a concentration gradient of a methane-air mixture have been measured on various flame curvatures in order to investigate the relation between the flame curvature and the burning velocity of Triple Flame. The flame curvatures are measured from the visible flame images. The unburned velocity and concentration fields are measured by PIV and Rayleigh scattering method. By combining the initial velocity and fuel concentration gradient of the mixture, two Triple Flames having the same curvature can be formed. From the result of the local velocity field and the local fuel concentration gradient ahead of the flame surface, it can be concluded that the local velocity and fuel concentration fields are similar when the flame curvature is similar. The burning velocity of Triple Flame has a good correlation with the flame curvature. It decreases monotonically as the flame curvature increases