Freezing dynamics of the ferrofluid droplet in a uniform magnetic field using the lattice Boltzmann flux solver

TL;DR

This paper introduces a novel enthalpy-based lattice Boltzmann flux solver to simulate ferrofluid droplet freezing under magnetic fields, revealing how magnetic orientation influences freezing time and droplet shape.

Contribution

The study develops a new numerical solver validated by benchmark tests and applies it to explore magnetic field effects on ferrofluid freezing dynamics, providing physical insights.

Findings

Magnetic field orientation alters droplet morphology during freezing.

Vertical magnetic fields elongate droplets, increasing freezing time.

Horizontal magnetic fields flatten droplets, decreasing freezing time.

Abstract

In this study, an enthalpy-based lattice Boltzmann flux solver is developed to simulate the freezing dynamics of a ferrofluid droplet under a uniform magnetic field. The accuracy and robustness of the solver are first validated through three benchmark tests: conductive freezing, static droplet freezing, and ferrofluid droplet deformation. The solver is then employed to investigate the influence of a uniform magnetic field on the freezing behavior of ferrofluid droplets, with particular emphasis on the overall freezing process, heat transfer characteristics, and freezing duration. The results reveal that the uniform magnetic field affects the freezing dynamics primarily by altering the droplet morphology. Under a vertically oriented magnetic field, the droplet elongates along the field direction, which increases the thermal resistance and consequently prolongs the freezing time. Conversely, a horizontally uniform magnetic field flattens the droplet, reducing the thermal resistance and thus shortening the freezing time. These findings provide new physical insight into magnetic-field-induced modulation of the freezing process in ferrofluid systems.