雙組份生質柴油、生質油料與柴油液滴燃燒行為之觀察

Abstract

由於現在化石燃料短缺的問題日益嚴重，所以進一步提升其使用效率成為一個重要的議題，觀察油料的燃燒行為可以幫助我們達到此目的。本實驗使用自由液滴法觀察了柴油、生質柴油、甲醇、乙醇、異丙醇等油料在不同比例下預混的燃燒行為，包括 :燃燒時間、點火延遲、燃燒速度和微爆現象等等。 實驗結果可以歸納成下面幾點: (一)在生質柴油中預混甲醇、乙醇後，點火延遲時間下降，且都會造成微爆發生所以燃燒時間也下降，燃燒速率上升。另外也會減少SOOT的生成，造成黃焰亮度下降。(二)生質柴油預混甲醇燃燒產生的微爆，型式可以分成三種：1.直接炸碎 2.液滴碎裂成多顆 3.主要液滴繼續燃燒形成分支；而生質柴油預混乙醇產生的微爆則主要都是火焰形成分支的形式。(三)高燃點液滴的點火和液滴大小有關。(四)若在柴油和異丙醇混和油料中加入水微爆會比較早，造成燃燒時間較短，點火延遲時間也較短，而微爆的提早發生也造成整體平均燃燒速率較高。

This research investigate droplets combustion by free droplet method with flat burner. The experiment mainly observed the ignition delay, burning time, normalized explosion diameter, burning rate of the fuel. And the micro-explosion phenomenon is recorded by the high speed camera. The fuel in this research are diesel, biodiesel, biofuel, naphtha, methanol, ethanol, 2-propanol. The results show that adding methanol and ethanol can reduce the production of soots and make the micro-explosion happen, reducing the burning time also increasing the burning rate of the fuel. When adding methanol into biodiesel, there will be three kinds of micro-explosion form. But adding ethanol into biodiesel, there will be only one form and the speed of micro-explosion is slower than adding methanol. Because naphtha is alkane, adding into biodiesel doesn’t change the too much. When adding 2-propanol & water into diesel, in spite of the small contain of the water,it will cause earlier micro-explosion compare to the diesel with 2-propanol only, and reduce burning time.