| Summary: | 碩士 === 國立臺北科技大學 === 機電整合研究所 === 95 === When the droplet is deposited on a hot enough surface, the bottom of droplet produces insulation vapor layer to cause the droplet evaporated slowly. This is called Leidenfrost Phenomenon. The lowest temperature occurring the Leidenfrost phenomenon is called the Leidenfrost temperature.
Some parameters affect the Leidenfrost temperature, such as size of droplet, thermal properties of liquid and heated surface, surface roughness of the heated surface, surface tension of the liquid, etc.
The experimentation, measuring evaporated time of the droplet and drawing evaporation curve beneath different temperature, is called Leidenfrost experiment. In addition to present transition boiling region successfully that we cannot attain through pool experiments, the Leidenfrost experiments better simulate the physical mechanism of spray cooling.
This investigation proceeds the Leidenfrost experiment with varied parameters, distilled water and saturated carbonated water of two kinds of concentration, four droplet sizes, and three kinds of heated surface material (6061 alloy aluminum, 6061 surface coating with Ti, 6061 surface coating with TiO2). According to the experimental results, evaporation curves are drawn, and the effects of dissolved gas, size of droplet, and surface coating are discussed.
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