Self-Propelled Water: Leidenfrost Effect at U of Oregon

[Mk]

http://www.uoregon.edu/~linke/dropletmovies/
The University of Oregon seems to be having fun using the Leidenfrost effect to propel droplets uphill, downhill, and all aroundhill.

This method uses heat to pump liquid, and could therefore be used in pumps for coolants, for instance to cool microprocessors. Such a pump would need no additional power (it's run by the heat that needs to be removed anyway), it would have no moving parts, and it wouldn't require a thermostat

NY times graphic.
http://graphics8.nytimes.com/images/2006/03/20/science/sciill900.jpg

 

[Clausius2]

Seems interesting. I don't understand very well the mechanism of how the droplet moves over the surface. It seems to me it's something to do with Hydrodynamic Lubrication effects (Re<<1) of lift and drag on the droplet. But I'm not sure.

 

[Astronuc]

Heat is thermal energy and that involves molecular motion. The motion has to do with wave propagation (momentum transfer) and phase of the waves with respect to the mass being moved.

I have seen something similar with fiber surfaces (like carpet) used to move objects forward or backward, based on frequency and amplitude.