Numerical simulation of droplet impingement on supercooled curved surface based on lattice Boltzmann method

Droplet impingement and freezing on supercooled curved surfaces is a widely encountered phenomenon in natural and industrial processes. In this study, based on the lattice Boltzmann method, we coupled a pseudopotential model, a modified thermal lattice Boltzmann equation for high liquid–gas density ratios, and a geometric contact angle model on curved surface to quantitatively investigate droplet impingement and freezing behavior in three-dimensional (3D) space. Enhancements include a tunable surface tension mechanism in central moment space and a consideration of volume change during solidification. Validation against static droplet contact angles, Laplace's law, and freezing-induced volume expansion confirms the model's accuracy. Through orthogonal experimental design, the effects of Weber number (We), wall temperature (Tw), contact angle (θ), and curvature ratio (κ) on droplet dynamics and phase transition are systematically investigated. Key findings reveal that contact angle dominates spreading behavior (contributing 48.8% axially and 53.6% circumferentially), followed by Weber number (47.1% axial and 38.5% circumferential effect). Wall temperature primarily governs freezing rate (48% contribution), while contact angle (30%), and Weber number (17%) indirectly influence solidification through droplet spreading behavior. Curvature ratio exhibits negligible effects (<5% contribution) in the range of the present work. This work clarifies multiphysics coupling mechanisms during droplet impact freezing on curved surfaces, providing theoretical insights for anti-icing surface design in industrial processes.