Understanding Flame Spread Across Alcohol Pools

Findings from recent experiments on flame spread across pure alcohol pools are presented with an emphasis on the effects of buoyancy, opposed forced airflow, and pool size. Predictions andlor experiments show gravity affects the spread rate at all initial pool temperatures, whether above or b e l ~ w the flash point. Pool dimensions also have a strong influence on both spread rate and spread behavior. At superflash temperatures, faster spread is found in microgravity (pg). At low pool temperatures, forced airflow is needed to sustain flame spread in pg, while in l g the flame sustains itself in a pulsating mode. As predicted, but not observed previously, experiments with shallow pools in an opposed airflow show pulsating spread in pg. Despite predictions of its existence, however, pulsating spread in pg with deep pools is not yet observed. Hypothesized causes of this disagreement and of pulsating spread in general are examined.