Numerical study of droplet impact on a superheated surface under an electric field based on perfect and leaky dielectric theories

Abstract

This paper investigates the hydrothermal behavior of leaky dielectric and perfect dielectric droplets impacting a superheated wall within a specific range of Weber numbers $\left(We\le 30\right)$ under an electric field. Through this investigation, we aim to provide a more comprehensive understanding of the dynamics involved in droplet-superheated surface interactions under electric fields, which can be useful in various applications, such as the design of cooling systems and combustion chambers. The study utilizes the level-set and ghost fluid techniques to capture the interface accurately. Under an electric field, different behaviors are observed during the impact process, depending on the electrical properties of the droplet. A perfect dielectric droplet experiences a reduction in spreading extent and an increase in contact time. However, no remarkable enhancement in total heat removal occurs in this case. For the leaky dielectric droplet exhibiting prolate deformation at the stationary state, increasing the electric field magnitude results in a slight decrease in the droplet spreading extent, while the droplet contact time and total heat removal from the surface increase. At an electric capillary number of 1.55E − 2 and a Weber number of 25, the enhancement in the contact time and total heat removal is about 43% and 15%, respectively. For the leaky dielectric droplet with oblate deformation at the stationary state, the spreading extent and total heat removal increase, with negligible changes in contact time. At the above-mentioned electric capillary and Weber numbers, the enhancement in the spreading extent and total heat removal is about 7.5% and 15%, respectively.