生質柴油與柴油混合醇類於微重力場下燃燒研究

Microgravity combustion of blended fuels with alcohol and biodiesel/diesel

邱明峻(Ming-Chun Chiu)

指導教授 ： 潘國隆

國立臺灣大學/工學院/機械工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.03293

摘要

本文利用落塔進行0.68秒的自由落體實驗以達到微重力的環境，並探討生質柴油、柴油液滴與甲醇、乙醇及丙醇混合後在無對流影響下的燃燒現象。並計算燃燒速率、碳殼(soot shell)尺寸與火焰直徑變化。微重力場下多組份生質柴油、柴油液滴的直徑變化、碳微粒的生成與火焰顏色將隨醇類組份的添加而有明顯的改變。
　　實驗結果顯示，生質柴油混合醇類(甲醇、乙醇及丙醇)於微重力燃燒過程中，容易因懸掛線或是內部雜質造成低沸點組份達到過熱極限發生液滴微爆(micro-explosion)現象。添加沸點越低的醇類越能提升燃燒速率，且隨著醇類比例增加可延遲碳殼的形成並縮短碳殼維持時間。柴油-生質柴油混合乙醇後碳微粒減少，且因為醇類會減弱碳殼的結構強度，可觀察到柴油堅固的碳殼會發生破裂。燃油分子被限制在密度較高的碳殼內於碳殼膨脹破裂時蒸氣竄出會發生火焰脹大現象。

關鍵字

微重力 ； 生質柴油 ； 醇類 ； 微爆 ； 碳殼 ； 碳微粒

並列摘要

Microgravity experiments were performed to investigate the combustion characteristics of blended fuels with alcohol(Methanol, Ethanol and Propanol) and Biodiesel/Diesel. The microgravity environment was made by a 0.68 second drop tower. Measurements include the burning rate , the formation of soot and flame structure. These experiments demonstrated significant influence of the increasing alcohol mass fraction. The information of evolution of droplet diameter, burning rate, soot shell diameter and flame diameter are reported.
　　The micro-explosion is observed for the binary component fuels mixed with alcohol because the fiber (or the internal impurities) is easier to achieve the limit of superheat. The results indicated that increasing the initial mass fraction of the alcohol, which has lower boiling point, increased burning rate, delayed the formation of soot shell and reduced the production of soot. The flame molecule restricted by the strong soot shell. The flame will be expanded instantaneously because of the vapour escaping from the broken soot shell.

並列關鍵字

microgravity ； biodiesel ； alcohol ； micro-explosion ； soot shell ； soot

參考文獻

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