Oscillations and island evolution in radiating diffusion flames

We show how an island (isola) evolves out of the usual S-curve of steady states of diffusion flames when radiation losses are accounted for and how it eventually disappears when radiation increases further. At small activation temperatures there are never any islands. We show that stable oscillations evolve first out of perturbations of steady states on the S-curve at large Damköhler numbers. Only if the activation temperature is large enough do they also appear on the islands. The region of the stable oscillations grows larger as activation temperature decreases.

Keywords: :

• Diffusion flames
• Hopf bifurcation
• stable oscillations
• stable limit cycle

Supported in part by the NASA–Glenn Microgravity Combustion Program, NCC3-662.