Ice crystal impact onto a dry solid wall. Particle fragmentation

In this experimental and theoretical study, the impact of non-spherical and spherical ice particles onto a solid surface is investigated. The impact velocity of the particles was varied between 1 and 74 m s−1. The size of the particles ranged from 30 μm to 3.5 mm. The impact target consisted of a tiltable aluminium surface. The impact angles were set to 30° and 90° (normal impact). The impact process was recorded by a high-speed video system. Based on observations, four different fragmentation modes, characterized by different levels of particle damage, were defined. Fragmentation models for the description of the deformation of the particle and the development of cracks within the particle on impact are formulated and validated by the experiments. In particular, the velocity up to which no particle fragmentation occurs, and the maximum velocity up to which minor fragmentation occurs (both significantly dependent on the particle initial size) are well captured by the fragmentation models.