Diesel–diesel and diesel–ethanol drop collisions

In view of the possible occurrence of unlike drop collisions in a diesel spray due to the increasing application of alcoholic fuels as supplementary fuels in diesel engines, collisions of a diesel drop with either a diesel drop or an ethanol drop were studied. Diesel drop collision results do not display appreciable difference, within experimental errors, from those of tetradecane drops except for very small Weber numbers. The collision of an ethanol drop with a diesel drop, when compared to binary diesel drop collisions, exhibits higher tendency towards reflex separation for near head-on collisions and lower tendency towards stretching separation for medium to high impact parameter collisions. These distinctions come from the spreading of ethanol over the diesel drop due to their difference in surface tension.