Near-limit oscillations of spherical diffusion flames

We examine the dynamic characteristics of the diffusion flame surrounding a droplet of liquid fuel in a reduced oxidant environment. The study is motivated by the experimental observations of candle flames in microgravity, which bear some similarity to the spherical diffusion flame that surrounds a burning liquid fuel droplet. The microgravity experiments reveal that, when the oxidant concentration in the chamber is sufficiently low, oscillations develop before extinction, A similar phenomenon is predicted here. An oscillatory state results for a sufficiently low oxidant concentration when radiative losses from the name are appreciable. The frequencies of oscillations we predict are in good agreement with the experimental observations.