INTERACTION BETWEEN 2 PREMIXED LAMINAR V-SHAPED FLAME FRONTS AT LOW LEWIS NUMBER

In studies of framelets in premixed turbulent combustion, the interact ion between laminar flames is of great importance. To study this, meas urements have been made of the interaction between two premixed lamina r V-shaped flames (''W'' configuration) for a Lewis number less than 1 . When the Lewis number differs greatly from unity, differential diffu sion effects dominate and lead to considerable complexity. Flow visual ization is used in association with laser Doppler velocimetry. Tempera tures are measured with a thermocouple and species are sampled through a probe. The results show repulsion between the two oblique flame fro nts separated by fresh mixture. This induces a divergent flow in the w hole interaction zone and an overall shifting of the two V-shaped flam es. The influence of the Lewis number is first noticeable on the unbur ned gases between the two flames since it induces preferential diffusi on of hydrogen in the transverse direction. This leads to an increase of temperature inside the two V-shaped flames. As a consequence, it al so prevents the intersection and coalescence of the two inner fronts a s they propagate towards each other. (C) 1997 by The Combustion Instit ute.