以往液滴撞擊熱表面的研究，研究對象多侷限在單一成份的液滴(單質液滴)或乳化液滴，對未使用界面活性劑而形成的多成份複合液滴尚未涉及。本研究採用連續液滴串的方式針對單核液-液複合液滴進行撞擊熱板的研究，其液滴組成是一顆液滴(外殼液滴)內部包含另一顆不同成份液滴(核心液滴)的結構。工作流體採用柴油為外殼液滴，而水為核心液滴。
在本研究中，我們發展了水-油複合液滴連續均勻液滴串的產製技術。利用這些均勻液滴串來撞擊熱板，我們探討了撞擊動量與碎裂型態的關係，並進行撞擊變形歷程的觀察、動量損失的分析及碎裂條件的預測，最後也針對停滯時間作量測。
研究結果發現對不同流體而言，反彈斷裂的臨界韋伯數及停滯時間與流體性質的關連性較強，而撞擊歷程及最大擴展直徑則與流體性質的關連性較弱。在本研究中，以能量守恆原理及液滴變形與能量逸散模型，我們推導了柴油液滴最大擴展直徑的表示式，經與實驗數據比較，可以相當正確地預估液滴最大擴展直徑；接著利用類似的能量逸散模型，我們也預測了複合液滴反彈斷裂臨界韋伯數，預測結果與實驗頗為吻合；另外研究也發現複合液滴正向動量損失隨正向韋伯數或質量比的增加而增加，而且核心液滴對撞擊行為的影響，隨著質量比增加而越顯著。在停滯時間方面，研究顯示在撞擊角 介於 的條件下，不管是單質液滴或複合液滴，撞擊熱板後在熱板的停滯時間皆與撞擊角 ，以及正向撞擊速度無關，而且證實柴油液滴及水¬-柴油複合液滴的停滯時間均與液滴外徑的3/2次方成正比。此外對複合液滴來說，核心液滴在複合液滴收縮反彈期間發揮「加速器」的功能，使得停滯時間縮短，而若以考慮界面特性的修正正向撞擊韋伯數 及無因次停滯時間 為座標繪圖，則所有實驗數據包括單質液滴與複合液滴，都幾乎落在同一條曲線 上。
本研究成果除了建立液-液複合液滴撞擊熱板的基礎知識，也釐清了一些單質液滴撞擊熱板的現象，同時也挖掘出許多問題，為後續研究者提供了繼續深入研究的門徑，此外相關數據也可以作為數值模擬的比對參考，使數值模擬的程式更臻完備。

The drops utilized for previous researches on the impingement of a drop onto a hot plate was found to be limited to a single-phase drop or an emulsion drop, and a multi-component compound drop was rarely used as the working fluid. Thus, we conducted an investigation on the collisions of a stream of compound drops impinging on a hot plate. The compound drop was composed of a core liquid, water, surrounded by a shell liquid, diesel oil.
In this study, we developed a method to produce a stable and uniform-sized water-in-oil drop stream. The phenomena of the impacts of either a pure diesel drop or a water-in-diesel compound drop was each experimentally observed and compared. Several topics including the relations between the impact momentum and the impact outcomes, the observation on the deformation processes, the prediction of the maximum spreading and rebounding disintegration, the analysis of the momentum loss, and the measurement of the resident time were discussed.
The results showed that the critical Weber number for rebounding disintegration and the resident time depended strongly on the properties of the working fluid; in contrast, the deformation processes and the maximum spreading depended weakly on the properties of the working fluid. Based on the principle of energy conservation and the model of dissipation, approximations of the maximum spreading of an impinging diesel drop and the critical Weber number for rebounding disintegration of a water-in-diesel compound drop were derived. These two approximations were in a good agreement with the experimental data. In addition, we found that the momentum loss of a water-in-diesel drop increased with increasing core-to-shell mass ratio. And the influence of the core-to-shell mass ratio on the impinging behavior increased while the core-to-shell mass ratio increased. For a diesel drop or a water-in-diesel compound drop with an outside diameter of , the resident time on the hot surface was found to be independent of the impinging angle and normal impinging velocity; and the resident time was proportional to . Also, for a water-in-diesel compound drop, the core drop acted as an accelerator to the rebounding process of an impinging compound drop on a hot surface; in other words, it reduced the resident time. All experimental data followed a single curve when they were plotted on the plane of the non-dimensional resident time and the modified Weber number. A good estimation for the resident time of a pure diesel drop and a water-in-diesel compound drop was found to be .
From the results of the present study, a foundation of the knowledge about the phenomena of a compound drop impinging on a hot plate is built and the understanding of the impact of a pure drop on hot walls is improved. By following the pace of the present study, new topics on the compound drop may be unveiled. In addition, the experimental results could also serve as references for numerical simulation.

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