雙組份燃油液滴於無重力場下之燃燒情形

An Experimental Study on the Combustion of Binary-Fuel Droplets under Microgravity Conditions

陳建培(Chien-Pei Chen)

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(2008年)

https://doi.org/10.6342/NTU.2008.01487

摘要

本實驗主要是利用自由落體之方式產生無重力場，使液滴於無對流效應之影響下燃燒及觀察其燃燒行為與特性，實驗所使用之單組份燃油有生質柴油、柴油，十二烷、十六烷、乙醇及十二醇，而雙組份燃油則有乙醇/生質柴油、十二醇/生質柴油與十二烷/生質柴油。

實驗結果顯示，對於會產生soot之燃料，液滴大小會影響燃燒速率，燃燒速率會隨著液滴初始直徑增加而降低。但對於不會產生soot之燃料而言，液滴直徑對燃燒速率之影響不大。乙醇於燃燒末期會發生熄滅現象。乙醇/生質柴油之雙組份液滴，於乙醇體積比為25%及50%時會產生微爆，但當乙醇體積比為75%時會發生熄滅現象。而十二烷/生質柴油之雙組份液滴，當十二烷之體積分率為60%以上時會發生火焰縮口之現象。然對十二醇/生質柴油之液滴而言，其體積分率與燃燒速率沒有直接的關聯性。

關鍵字

液滴 ； 無重力 ； 燃燒 ； 微爆 ； 火焰縮口

並列摘要

Making use of freely falling in the experiment generates microgravity conditions, which can provide an environment for the droplets combustion without the convection, and enables us to the observe characteristics of combustion. The single-component fuels used in this experiment were biodiesel, diesel, dodecane, hexadecane, ethanol and dodecanol, the droplets of binary fuel mixtures include ethanol/biodiesel, dodecanol/biodiesel and dodecane/biodiesel.
The experimental results showed that the burning rate would decrease with increasing the initial droplet diameter for sooting fuels. In contrast to sooting-free fuels, the burning rate is almost independent of the initial droplet diameter. Ethanol droplets will extinguish when the combustion process come to an end. The micro-explosion is observed for ethanol/biodiesel mixtures when the volume fraction of ethanol is 25% and 50%, but the droplets will extinguish for the 75% volume fraction of ethanol. The flame shrinkage is observed for the volume fraction of dodecane above 60% for dodecane/biodiesel. The burning rate is almost independent of the volume fraction for dodecanol/biodiesel droplets.

並列關鍵字

droplet ； microgravity ； combustion ； micro-explosion ； flame shrinkage

參考文獻

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