Leidenfrost water droplets can self-propel on heated surfaces with ratcheted topography, a very useful characteristic for systems with excess heat where fluid flow without moving parts is desirable. Reliability and flow rate are significant concerns for such systems. Here, the effect of the surface profile on reliability and droplet velocity are investigated on a single device with a continuously adjustable millimetre-scale ratcheted surface. Conditions are described under which the droplet velocity can exceed 350 mm/s. The reliability of droplet propulsion is shown to be improved for ratchet geometries with an overhang.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)