| Wed January 6th 2016 16:00 – 16:30 ZH286 | Seminar | TIR-imaging and its application to droplet impact on a superheated solid surface Minori Shirota |
Details:It is well-known that when a droplet approaches an unheated solid surface, a dimple is formed on the base of the droplet and the neck around the dimple first touches the solid. However, in the case of Leidenfrost droplet impact on superheated solid surfaces, so far it has not yet been clear whether or not the neck around the dimple forms and rams the solid surface. One could argue that the vapor generation might smoothen out the neck structure and therefore the touch-down might be prevented by the same mechanism as in static Leidenfrost boiling. We for the first time investigate the dimple structure of the Leidenfrost impacting droplet using total internal reflection (TIR) imaging. TIR-imaging is a powerful technique to quantitatively evaluate the approach of impacting droplets on an evanescent length scale, typically 100 nm, and to clearly distinguish the wetted area from vapor bubbles/patches on heated substrates. At the end of the talk, some remarkable wetting/drying behavior in the transition regime between the contact and the Leidenfrost boiling will be also presented. | ||
