多顆液滴交互作用對燃燒特性及行為的影響

An Experimental Study on Interaction and Burning Characteristic and Behavior of Several Droplets

宋柏毅(Bo-Yi Sung)

指導教授 ： 王興華

國立臺灣大學/工學院/機械工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.00788

摘要

本實驗使用噴墨壓電法產生穩定的單方向擴散液滴，進入加熱的石英玻璃管內燃燒。以往的實驗都是將液滴分得很開去探討單顆獨立燃燒的行為，本實驗將電子控制箱對液滴產生器和閃頻儀的訊號頻率調高，使得液滴間距離減少，如此一來便可探討當液滴彼此影響時對燃燒速率、燃燒時間的影響。在多顆液滴落下燃燒時，其速度和加速度也會因液滴數量增加而受到影響。根據前人的一些研究，可得知會影響到液滴彼此行為的因素是液滴的間距，而此距離並不是尺寸上的距離，而是液滴直徑的倍數，所以越大顆的液滴，如果希望彼此不會互相影響，所需要的距離就會越長。
除了形成一整條液滴陣列之外，本實驗特別討論只有兩顆在空間中互相影響的行為。結果發現連續液滴彼此距離減少時燃燒效率會降低，低頻雙顆液滴距離減少時上游液滴沒有影響，而下游液滴燃燒效率會增加。雙顆間距繼續減少時，會發生火焰分燒的現象，而且初始間距越小會使分燒幅度越來越大。

關鍵字

液滴 ； 燃燒時間 ； 燃燒效率

並列摘要

Ink-jet method was used in this experiment to steadily generate the mono-dispersed droplets stream, and they were then burned within a flat-flame heated environment confined with the quartz tubing. Early studies separated the droplet into a significance distance in order to observe the behavior of the single droplets’ combustion. In the report, the droplet generation frequency could be varied widely to study the burning characteristics due to droplet-droplet interaction. According to the recent studies, we could infer that the main factor can influence the droplets’ behavior is the space, which is measured by the droplet’s diameter. The bigger droplets, the longer space we need to avoid interaction.
In addition to an array of droplets, two droplets’ burning characteristics are discussed in this thesis as well. The results show that burning rate will decline when space between droplet array decrease. In the low frequency and two droplet situation, the first droplet’s combustion rate won’t be affected but the second one’s will increase. However, further decreasing their initial separation distance, the second droplet will start to deviate from its proposed trajectory and then form a Y-shape flame.

並列關鍵字

droplets ； burning time ； burning rate

參考文獻

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