Solidification is an important issue that needs to be addressed when modelling supercooled large droplets (SLD) impacting aircraft surfaces. This work develops a 3D triple-phase smoothed particle hydrodynamics (SPH) solver that can simultaneously simulate SLD impingement and solidification on cold surfaces by solving the Euler equations for fluid dynamics, the energy equation for heat transfer, and a latent heat model for phase changes. The solver is validated against a Stefan problem in which a liquid is cooled and solidified by a cold boundary, and against a still droplet freezing on a cold plate. It is then applied to droplets impacting on cold surfaces at aeronautical speeds, analysing the freezing time and ice particle distributions as the droplet velocity and impact angle are varied. This is an important step towards a macroscopic numerical model of SLD post-impact behaviour for in-flight icing simulations.

在对撞击飞机表面的过冷大液滴 (SLD) 进行建模时，凝固是一个需要解决的重要问题。这项工作开发了一个 3D 三相平滑粒子流体动力学 (SPH) 求解器，它可以通过求解流体动力学的欧拉方程、传热的能量方程和相变的潜热模型，同时模拟冷表面上的 SLD 撞击和凝固. 该求解器针对 Stefan 问题进行了验证，在该问题中，液体通过冷边界冷却和凝固，并针对在冷板上静止的液滴冻结。然后将其应用于以航空速度撞击冷表面的液滴，分析液滴速度和撞击角度变化时的冻结时间和冰粒分布。