Atomization and combustion characteristics of a biodiesel–ethanol fuel droplet in a uniform DC electric field

Electric field has the potential to influence the combustion characteristics of hydrocarbon fuel. In this paper, the atomization and combustion characteristics of the droplets of biodiesel and biodiesel–ethanol blend in a uniform direct-current electric field were investigated using photography. It was revealed that a certain electric field strength could induce droplet deformations and cone jets. For the droplet blended with 10 vol. % ethanol, the sizes of the secondary droplets from bubble breakups decreased with the increase in electric field strength, possibly due to the Coulomb repulsion in the ligament. The high breakup intensity of the droplet blended with 30 vol. % and 50 vol. % ethanol covered up the effect of electric field on the sizes of secondary droplets from bubble breakups. During the entire range of electric field strength, cone jets generated smaller secondary droplets in comparison with bubble breakups. Moreover, the electric field distorted the flame morphology, especially the flame width increased at the electric field strength of 50 kV/m. The maximum droplet temperature decreased with the electric field strength, in addition to the biodiesel droplet. Overall, the electric field ameliorates fuel droplets' atomization and combustion characteristics.