Boiling regimes of impacting drops on a heated substrate under reduced pressure

Drops impacting a sieve.

We study experimentally the impact of liquid drops against thin plates pierced with small holes. When the drop is larger than the hole, different situations can occur: (i) at a small velocity, the drop is entirely captured by the plate; (ii) above a threshold speed, some liquid is ejected below the surface. We characterize this critical speed and these two different situations, focusing on the ...

On the spreading of impacting drops

The energy budget and dissipation mechanisms during droplet impact on solid surfaces are studied numerically and theoretically. We find that for high impact velocities and negligible surface friction at the solid surface (i.e. free-slip), about one half of the initial kinetic energy is transformed into surface energy, independent of the impact parameters and the detailed energy loss mechanism(s...

Evaporation and Explosion of Liquid Drops on a Heated Surface

The literature pertinent to various aspects of drop evaporation on a heated surface is reviewed. Both the laser shadowgraphic and direct photographic methods are employed to study thermal stability and flow structures in evaporating drops in all heating regimes. It is revealed that four flow regions exist in stable and unstable type drops at low liquid-film type vaporization regime. As the surf...

Can multiple flow boiling regimes be reduced into a single one in microchannels?

Skating on a film of air: drops impacting on a surface.

The commonly accepted description of drops impacting on a surface typically ignores the essential role of the air that is trapped between the impacting drop and the surface. Here we describe a new imaging modality that is sensitive to the behavior right at the surface. We show that a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the sur...