Cellular Flames

Of particular interest in fundamental combustion research is flame instability. Their occurrence causes drastic changes in flame structure, and allow complex structures to exist in relatively simple flow-fields.

Shown to the right are rich butane flames sustained on a spherical burner. Two flames are sustained simultaneously: a cellular premixed flame (light blue) near the burner surface, and a non-cellular diffusion flame (dark blue). Due to the near-zero flame stretch, the cellular patterns are not ordered along any particular direction.

This instability is strongly governed by transport properties, and forms uniquely beautiful patterns of reaction and extinction. The study of cellular flame behavior allows the dual benefit of better understanding the instability itself as well as the transport phenomena that govern it.

Shown on the left is a premixed flame, sustained in a stagnating jet. The flame experiences non-zero stretch along the radial direction, which orders the cellular patterns along the azimuthal direction.

In our lab, the symmetry of cellular patterns in stretched flames is exploited as much as possible. This allows for clearer conclusions and drastically simplifies parameter studies to map the cellular behavior. Check our links to the left for more information on our lab’s research.

Images courtesy of S. H. Sohrab