Ice crystal impact onto a dry solid wall. Particle fragmentation

Abstract

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.

Solidification dynamics of an impacted drop

“…Understanding the coupling between drop impact hydrodynamics and solidification, that builds the frozen structure, is crucial in many different contexts : airplane icing (Baumert et al 2018), ice accretion on wires or roadways due to freezing rain (Jones 1998), 3D printing (Lipson & Kurman 2013), surface metal coating technology (Pasandideh-Fard et al 2002;Fauchais et al 2004), etc. Indeed, although most of the airplane icing configurations concern impact of ice crystal (Vidaurre & Hallett 2009;Hauk et al 2015), the impact of water droplets on subfreezing substrates can be of great interest in the dynamics of icing formation (Schremb et al 2018). Today, the optimal design and coating of the surfaces to avoid icing remains an important open problem (Cao et al 2009;Kreder et al 2016).…”

Eulerian method for ice crystal icing in turbofan engines

“…Vidaurre and Hallett [136] assumed the reference surface energy e σ0 to be 0.12 J/m 2 at T 0 = 253 K. Higa et al [55] stated that the activation energy Q s is equal to 48.2 kJ/mol. Impact experiments of Higa et al [55], Vidaurre and Hallett [136], Guégan et al [47] and more recently from Hauk et al [51,52] confirm that two critical values of L can be defined that identify three possible impact regimes:…”

“…The unit tangential vector t can be randomly chosen as long as it is tangential to the impact surface. The diameter of the secondary particles and the restitution coefficients have been derived from the experimental results of Higa et al [55] and Hauk et al [51,52]. The diameter d max corresponds to the largest particle fragment and is given by…”

“…Large particle (0.3-2.5 mm diameter) impacts were obtained using a heated cloudscope mounted on a NASA DC-8 aircraft. These measurements were collected over the central Pacific and over Particle impact velocity as a function a particle diameter from Hauk et al [52]. The experimental data obtained for spherical and non-spherical particles is shown for impacting particles displaying no fragmentation or only minor fragmentation.…”

“…Both studies confirmed that the secondary fragments of the ice particles exhibited the same behaviour in terms of size, and magnitude and direction of secondary velocity as observed for hailstones. In the framework of HAIC, Hauk et al [51,52] have investigated the impact of even smaller ice particles, in the diameter range of 30 µm to 3.5 mm. The particles were shot at an aluminium surface mounted in a cold test section.…”