Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (1): 32-40.doi: 10.3866/PKU.WHXB201411051

• THERMODYNAMICS, KINETICS, AND STRUCTURAL CHEMISTRY • Previous Articles     Next Articles

Fluorescence Spectra of Polycyclic Aromatic Hydrocarbons and Soot Concentration in Partially Premixed Flames of Diesel Surrogate Containing Oxygenated Additives

ZHANG Peng, LIU Hai-Feng, CHEN Bei-Ling, TANG Qing-Long, YAO Ming-Fa   

  1. State Key Laboratory of Engines, Tianjin University, Tianjin 300072, P. R. China
  • Received:2014-07-31 Revised:2014-11-05 Published:2014-12-25
  • Contact: LIU Hai-Feng E-mail:haifengliu@tju.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51206120).

Abstract:

Partially premixed laminar flames were formed using our purpose-built burner. The soot reduction mechanism of blends of diesel and oxygenated fuel was explored. The mixture of toluene and n-heptane (volume ratio, 20:80) (T20) was used as a diesel surrogate. Methanol, ethanol, n-butanol, methyl butyrate, and 2,5-dimethylfuran (DMF) were blended with T20, whilst retaining a 4% oxygen content. Laser-induced fluorescence (LIF) was used to obtain spatial fluorescence spectra of polycyclic aromatic hydrocarbons (PAHs) in partially premixed co-flowflames. Laser-induced incandescence (LII) was used to measure soot concentration (volume fraction). The formation and growth of PAHs in flames varied with the fuel blend. Four-ring aromatics (A4) exhibited similar formation and oxidation to soot, so A4 was suitable for estimating soot formation and oxidation. With oxygenated additives, the content of toluene is reduced in T20 fuel, which is the major reason for the reduction of PAH fluorescence spectral intensity and soot concentration. The contribution of different oxygenated additives to PAH formation also affected soot reduction. The PAH-LIF spectral intensity and soot concentration of n-butanol /T20 blends were lower than those of fuels containing methanol, ethanol, methyl butyrate, and DMF. Therefore, n-butanol more effectively reduced PAHs and soot emission during the combustion of the diesel surrogate (T20).

Key words: Oxygenated fuel, Polycyclic aromatic hydrocarbon, Soot concentration Laser induced fluorescence spectrum, Laser induced incandescence

MSC2000: 

  • O643