中文摘要：

利用铝片制备了不同倾角和高度的锯齿状结构表面,采用高速摄影仪对高温锯齿状表面自推进液滴的动态行为特征进行了研究.结果表明,液滴在锯齿结构表面随温度变化会呈现不同的动态行为,只有当表面温度达到Leidenfrost温度时,才会形成稳定的Leidenfrost液滴和自推进现象.对于一定几何尺寸的锯齿状结构表面,随着其表面温度的升高,自推进液滴的初始加速度先增大然后减小,即液滴存在最大加速度及其对应的最佳温度值.此外,在相同温度的不同锯齿状结构表面,当锯齿高度相同时,锯齿倾角对液滴加速度影响显著,锯齿倾角越大,液滴自推进加速度越大,并且液滴自推进加速度和温度的变化关系与液滴体积无关.建立了模型对高温表面液滴自推进现象的动态特征进行了机理分析.

英文摘要：

In recent years, self-propelling fluidic devices have received particular attention, due to their unique abilities to displace liquid at small scales without an external force. The ability to control the dynamics of liquids is crucial in applications such as thermal management, ink-jet printing, 1ab-on-a-chip technology and spray cooling. As known, Liquid spilled on a hot surface rapidly evaporates. At the Leidenfrost temperature, well above the boiling point, one observes long-lived droplets that levitate because of the excess pressure resulting from the permanent feed of vapor at the bottom of the droplet. So millimeter-scale liquid droplets on substrates can move spontaneously due to the animbalance of surface tension forces caused by a thermal gradient, and that makes Leidenfrost droplets very mobile because of their contact-free suspension. In recent years, using the Leidenfrost droplets to control wetting condition of droplet, the new phenomenon, named the self-propelled droplet, had been found that the droplets can move at a well-defined direction on some surfaces such as ratchet surfaces. However, according to the literature published recently, the relationship between the dynamic characteristics of self-propelled droplets and the ratchet structure parameters was not clear, and the mechanism of the Leidenfrost droplets was not clear either. So the different ratchet-structured surfaces were prepared with the aluminum sheet in this work. The dynamic behaviors and the mechanism of self-propelled droplets on hot ratchet surfaces were studied by analyzing the images captured by a high speed camera at the frame rate of 1435 Hz. The data were acquired with image analyzing technology. Ratchet surfaces were heated on constant temperature heating units. Deionized droplets with different volume V were deposited on hot ratchet surfaces with different inclination 0 and height H at different temperature T. The relationship among the various parameters was analyzed and the dynamic characteristics of droplets varied with