Basic Research of Single Droplet Combustion Behavior of Water-Containing Ethanol Fuel

Concerns about global warming have led to a demand for the use of carbon-neutral fuels, and bioethanol which is already widely used is particularly promising. However, ethanol produced by fermentation contains large amounts of water, and separating it requires a significant amount of energy. In this report, we conducted basic combustion experiments of water-containing ethanol droplets, with the goal of effectively utilizing ethanol containing a certain amount of water. Using suspended droplets, effect of water content on the amount of heating for ignition and burning rate constants were investigated. As a results, ignition became more difficult as the water content of ethanol increased, and ignition was particularly difficult at a water content of 50%. When water content is from 20% to 40%, extinction is observed after the ignition. The burning rate constant decreased as the water content increased, and a particularly rapid decrease was observed at 40% and above. Relation between the amount of heat during ignition phase and the heat release during combustion is to be discussed.