Study of Cryogenic Film Boiling in the Presence of External Electric Field Using a Variant of Volume of Fluid-Based Interface Tracking Algorithm

Abstract

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.

Design of a Smart Wettability-Regulating Surface for Enhancing Pool Boiling Heat Transfer Using the Lattice Boltzmann Method

“…31 With the rapid development of computer technology and advanced numerical methods, researchers are increasingly using numerical simulations to study the complex physical problem of BHT. 32 It is possible to change the wettability of the heating surface without tuning the surface structures. Among numerical methods, the lattice Boltzmann method has marked advantages for investigating multiphase flow, especially for the phase change process.…”

“…Moreover, wettability usually changes with surface structure, though few experimental studies have decoupled these effects . With the rapid development of computer technology and advanced numerical methods, researchers are increasingly using numerical simulations to study the complex physical problem of BHT . It is possible to change the wettability of the heating surface without tuning the surface structures.…”

Simulation of Slag Droplet Entrainment by Volume of Fluid and Lagrangian Particle Tracking Coupled Modeling

“…Since the steel–slag interaction usually leads to complicated phase structures with a wide range of temporal and spatial scales, a single numerical method usually fails to predict the phenomena accurately. There are four main types of simulation methods for multiphase flows, namely, mixture models, interfacial models, , multi-fluid models, , and Eulerian–Lagrangian (EL) models. − Among these models, the interfacial models mainly include the volume of fluid (VOF), level-set (LS), etc. However, the breakup of the slag layer usually produces small-scale droplets from the large-scale interface, and combined models, usually regarded as multiscale models, should be applied.…”

Machine Learning Approach for Predicting Minimum Film Boiling Temperature Considering the Surface Roughness Effect

“…The temperature at which this boiling transition occurs is referred to as the Leidenfrost temperature or the minimum film boiling (MFB) temperature, denoted T min . This threshold temperature holds immense significance in the industrial design of nuclear reactors, cryogenic milling, and grinding. , For example, for accurate estimation of the liquified natural gas (LNG) spill consequence, the transition of film boiling must be taken into consideration . By understanding and accurately determining the MFB temperature, engineers and researchers can optimize the performance and efficiency of various industrial processes and systems.…”