Evaporation and combustion characteristics of an ethanol fuel droplet in a DC electric field

The combustion process of droplet in an electric field is observed experimentally. The deformation and temperature of flame and droplet are obtained, and the combustion rate constant is calculated. The results show that the combustion process of droplet is significantly influenced by the electric field. When an electric field is applied, the initial shape of the droplet is elongated. The flame is brighter, the droplet shape is more stable, the flame height decreases significantly and the flame width increases slightly. When the electric field is applied, the combustion time is reduced by 14.9% compared with the condition without the electric field. With the electric field intensity increasing, the flame temperature increases firstly and then decreases, the droplet temperature decreases and the evaporation temperature decrease. When the electric field is applied, the maximum temperature of the flame measured increases by 17.6%, the maximum temperature of the droplet measured decreases by 12.9% and the evaporation temperature measured is reduced by 4.2% compared with the condition without the electric field. The electric field mainly affects the shape and temperature of flame and droplet, but the effect on the combustion rate is not obvious. The fluid flow is accelerated and the heat transfer is enhanced. The electric field charges the droplet and the directional movement in the droplet is enhanced, which promote the evaporation. At the same time, the droplet evaporates and combusts at a lower temperature, which partially counteracts the promotion caused by the flow acceleration. This study gives an insight into the effect of applied electric field on the combustion of liquid fuel in a new perspective of evaporation.