On droplet spreading/splashing transition and droplet icing on engineered surfaces
Maria Rosaria Vetrano
Abstract: The impact of liquid droplets on surfaces is a fascinating phenomenon with significant implications
in daily life, nature, and industrial processes. In nature, these impacts play a vital role in spreading
nutrients and microorganisms, affecting ecosystems and agriculture. Similarly, in industry,
understanding droplet behavior enhances the design of technologies such as inkjet printing, cooling
systems, and spray coatings.
In this framework, this talk aims to discuss two specific phenomena taking place during the droplet
impact with a surface.
- The first focuses on the presence of a small fraction of nanoparticles in a fluid on both the
dynamic and thermal behavior of droplet impact on flat surfaces. I will show that using a
nanofluid does not modify the non-monotonic behavior of the spreading-to-splashing
transition but influences its boundary by promoting splashing at low Reynolds numbers. This
can be associated with a change in the lamella spreading speed and lift during the initial
droplet spreading stage.
- The second regards the cooling droplets impacting cold surfaces (down to - 40 degrees) and
the related heat transfer and icing process. I will show that freezing can take place following
different mechanisms and stages depending on the surface wettability (i.e. surface level of
hydrophobicity
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