Micro-explosion and burning characteristics of a single droplet of pyrolytic oil from castor seed

國際期刊
2017 - 01

Journal: Applied Thermal Engineering, vol. 114, pp. 1053-1063, 2017.

Title: Micro-explosion and burning characteristics of a single droplet of pyrolytic oil from castor seed 

Authors: Guna-Bang Chen*, Yueh-Heng Li, Ching-Hsien Lan, Hsien-Tsung Lin, Yei-Chin Chao**

Rank: <8%(10/133), SCI, MECHANICS, 2016.

 

Heating processes of a droplet at an ambient temperature of 550 C. At 550 C, low boiling components inside the droplet are heated rapidlyand volatilization and nucleation occur instantaneously. The pressure inside the droplet quickly increases, and the droplet begins to swell and burst with a strong micro-explosion at a temperature of about 200 C, accompanied by a certain amount of oil and gas release from the droplet interior. Volatile vapor is released in the previous stage and the flammable mixture is ignited to form a non-premixed flame wrapping around the droplet Combustion accelerates the heating rate of the droplet, and micro-explosion continues to occur because of the nucleation of volatile compounds inside the droplet. The droplet shape is dramatically distorted, and the release of oil and gas affect the appearance of the flame.

Abstract: In the study, castor pyrolytic oil is produced from castor seeds by thermal pyrolysis and its pyrolysis reaction and oxidation reactions are investigated using thermogravimetric analysis. The results are also used to evaluate the characteristic combustion properties, such as the ignition temperature, burnout temperature and combustion characteristics index. The suspended droplet experimental system is also used to explore the micro-explosion phenomena and combustion modes of castor pyrolytic oil under different ambient temperatures. The castor pyrolytic oil is a multi-component fuel and has a complex process during the heating process and micro-explosion occurs, causing the droplet surface distortion. According to the timing and strength of the micro-explosion, there are three different stages: low intensity microexplosion in the first stage, high intensity micro-explosion in the second stage and medium intensity micro-explosion in the final stage. After high-intensity micro-explosion occurred at 550 C, more volatile vapors were released and the flammable mixture will formed a flame wrapping around droplets after ignition. During the droplet combustion process, the micro-explosion occurred continuously, but the droplet still maintained a sphere-like appearance. The variation of droplet size generally followed d2-law and the combustion rate constant is approximately 1.483 mm2/s.

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研究成員

  • 李約亨

  • 陳冠邦

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