Abstract
To explore behavior of near extinction flamelets in turbulent premixed flames, emission intensities of OH, CH and C2 radicals of hydrocarbon-air premixed flames have been examined using the newly developed emission spectroscopy system. It has been shown in our previous study that the emission intensity ratio of 515nm/470nm bans of C2 radical uniquely depends on the temperature of unstained methane/air and propane/air flames. In the present study, dependence of the emission intensity ratio of 515nm/470nm bans of C2 radical on the strain rate has been examined using a counter flow burner. As the strain rate increases, both the flame temperature and the emission intensities of C2 radical decreases. The flame temperature monotonically decreases as the emission intensity ratio of 515nm/470nm bans of C2 radical decreases. It is concluded that the temperature of a flamelet of turbulent premixed flames can be estimated by measuring the emission intensity ratio of 515nm/470nm bans of C2 radical.
