![]() ![]() In the hovering stage, the Laplace force played an important role, which was the main reason for the rebound of the droplet, while the role of the aerodynamic force was to keep the droplet on the surface of the gas film. The results showed that the motion of pseudo-Leidenfrost droplets in a period could be divided into three stages: falling, hovering, and rising. Weber number conditions for droplets triggering the pseudo-Leidenfrost phenomenon were revealed. Besides, the pseudo-Leidenfrost phenomenon of FC40 droplets with various Weber number was investigated. The mechanical analysis of the FC3283 droplet in a pseudo-Leidenfrost period was analyzed. The velocity of micro-airflow and pressure distributions at the bottom surface of the droplet, which were similar to the Leidenfrost phenomenon, were revealed. The oscillation of the droplet in the vertical direction was analyzed by tracking the position of the droplet centroid. By FC3283, it is an extremely low surface tension working medium with thermal stability at room temperature. ![]() Both experimental and numerical studies were carried out to investigate the pseudo-Leidenfrost effect of the FC3283 (perfluorotripropylamine) droplet. Inspired by the Leidenfrost phenomenon, a pseudo-Leidenfrost system was established innovatively through micro-airflow rather than evaporated vapor to lift a droplet. Our work is attractive for applications under the conditions of required traveling speed and direction of droplet.ĭroplet regulation has significant application potential in many fields however, conventional controlling methods make it difficult to effectively control low surface tension droplets. The scale law analysis explains the droplet size effect on the self-propelling droplet dynamics. We show orbit lines passing through a focusing spot that is ~1% of the Leidenfrost surface area around its center, with a maximum traveling speed of ~85 cm/s, which is ~2 times of that reported in the literature. The suppression of the thrust force relative to the inertia force regulates the droplet trajectory as it passes through a target location. ![]() The symmetry breaking of explosive boiling creates a thrust force that is sufficient to propel the droplet. For droplet-wall collision with SRES, micro/nano scale roughness not only enhances energy harvesting from the skirt ring to the droplet due to increased radiation heat transfer, but also provides nucleation sites to trigger explosive boiling. Our system consists of two surfaces that have different functions: a smooth surface running in the Leidenfrsot state for droplet levitation, and a skirt ring edge surface (SRES) as an explosive boiling trigger. Here, for the first time, we demonstrate a novel mechanism for the control of droplet dynamics by explosive boiling. Leidenfrost droplet possesses ultra-low flow resistance, but it is challenging to obtain large thrust force for fast transportation and regulate the direction of droplet motion. ![]()
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