The study of film boiling of cryogenic fluids has become a topic of interest due to its applications in several areas, including electronic cooling and space vehicles. In this paper, numerical simulations were conducted to investigate the film boiling of liquid nitrogen using a variant of the volume of fluid (VOF)-based algorithm. The effects of wall superheats and electric fields on the bubble dynamics during film boiling at normal atmospheric pressure and near-critical conditions were investigated. It was observed that bubble formation during film boiling of liquid nitrogen at lower wall superheats was governed by Rayleigh−Taylor instability. However, at higher wall superheats, bubble spacing decreased with the appearance of additional bubbles. The average heat transfer rate increased with an increasing wall superheat. The electric field significantly influences the film boiling up to a specific limit of wall superheat. At a higher wall superheat, the influence of the electric field was suppressed by the enhanced thermal effect. It was observed that the impact of the electric field on film boiling is highly dependent on the dielectric permittivity difference between the liquid and vapor phases. Faster bubble detachment and reduced bubble spacing were noticed in the presence of an applied external electric field.

No abstract

No abstract

No abstract