NEAR-LIMIT OSCILLATIONS OF SPHERICAL DIFFUSION FLAMES

We examine the dynamic characteristics of the diffusion flame surround ing a droplet of liquid fuel in a reduced oxidant environment. The stu dy is motivated by the experimental observations of candle flames in m icrogravity, which bear some similarity to the spherical diffusion fla me that surrounds a burning liquid fuel droplet. The microgravity expe riments reveal that, when the oxidant concentration in the chamber is sufficiently low, oscillations develop before extinction, A similar ph enomenon is predicted here. An oscillatory state results for a suffici ently low oxidant concentration when radiative losses from the name ar e appreciable. The frequencies of oscillations we predict are in good agreement with the experimental observations.