油/水/酒精之乳化液的噴霧燃燒現象研究

Investigation on the Characteristics of Spray Combustion with Kerosene/Water/Ethanol

鐘崑鳴(Kun-Ming Chung)

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.2011.00177

摘要

本實驗在一開放空間下進行噴霧燃燒之實驗研究，並以煤油為基底，分別混合水以及乙醇，製成乳化液及混合燃料。並在固定燃料流量的情況下輸入不同流量之空氣，以期能了解火焰於不同空氣流量下之表現。實驗中首先觀察火焰的外觀，發現到煤油加入水後火焰顏色會由原先的黃色逐漸轉為橘黃色，亮度也會明顯下降；而煤油與乙醇之混合則在外觀上無明顯變化。而不論哪種油料在空氣流量逐漸增加時，火焰根部之顏色皆會有部分或全部呈現藍色。接著由外觀量測火焰的高度，發現到在煤油中加入水或乙醇皆有助於高度的減少，而其中加入水所減少的幅度又較乙醇增加的多。最後則量測火焰軸向以及徑向的溫度，在空氣流量較低時，乳化液會使得火焰較為高溫的區域擴大，這是因為微爆現象的發生使得液滴碎化，增加了火焰內部的燃燒效率，因此高溫的區域擴大了。但在流量較高時，微爆效應逐漸被乳化液內含的水吸收熱能所取代，因此火焰的溫度反而下降了。過多的水分同時也會降低火焰的穩定度，因此火焰被高空氣流速吹熄。而乙醇的加入雖然增加了燃料蒸發效率，但在溫度變化上面與純煤油相比並不明顯。

關鍵字

噴霧燃燒 ； 乳化液 ； 微爆 ； 乙醇

並列摘要

The experiments carried out in an open space of the experimental study of spray combustion, use kerosene as the base, respectively, mixed water and ethanol, made from the emulsion and mixed fuel. Besides, we fixed the fuel flow rate, in order to know flame behavior at different air flow rate. First, we observe the flame appearance, find out the flame color transforms from yellow to orange when water added in kerosene, at the same time, luminosity decrease. However, there is no evidence change when kerosene mixes with ethanol. No matter what fuel applies, the color of root of the flame appears partially or totally blue when the air flow rate gradually increasing. Then measuring flame height from flame appearance, find out flame height decreases when kerosene mixes with water or ethanol, moreover, the flame height decreases is larger as water add in kerosene than ethanol add in kerosene. Finally, we measure flame axial and radial temperature, at low air flow rate, emulsion fuel will increase high temperature zone because micro explosion phenomenon occur, fuel droplet erupt, increase combustion efficiency in the flame. However, under high air flow rate, the effect of micro explosion is replaced by absorption of water which exist in emulsion. Therefore, flame temperature decrease. Too much water will also reduce flame stability, so the flame is blown out by high air flow rate. Although fuel evaporation rate increase when ethanol added, there is no evidence variation in temperature, compared with kerosene.

並列關鍵字

spray combustion ； emulsion ； micro explosion ； ethanol

參考文獻

[21] 謝恆晟，柴油/生質柴油與水/酒精之乳化液的噴霧燃燒，國立台灣大學機械工程研究所碩士學位論文，民國九十九年。

[30] 蘇陳泓學，生質柴油、水和醇類直接乳化穩定性及燃燒現象研究，國立台灣大學機械研究所碩士論文，民國九十六年。

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