Concerning the Luminosity of Methanol-Hydrocarbon Diffusion Flames

Abstract Luminosity of methanol-hydrocarbon diffusion flames was studied as a function of liquid fuel composition. Wick flames were used. Fuel compositions producing low-luminosity and high-luminosity flames are separated by a concentration threshold whose location varies among different hydrocarbon cofuels. Cofuels that burn individually to form large amounts of soot, e.g., xylene, exhibit lower thresholds than confuels that burn forming little soot, e.g., n-hexanol. Luminosity studies of small pool fires were performed. Distillation effects are severe. With solutions of low-boiling hydrocarbons in methanol the hydrocarbons are selectively vaporized out of pool liquid, and burned, during early stages of the pool fire. This produces high initial flame luminosity which later decreases as the residual pool liuqid is enriched in methanol. In contrast, selective methanol vaporization occurs during pool fires involving methanol solutions of high-boiling hydrocarbons; e.g., xylene. Here initial flame luminosity...