Numerical Study of the Formation of Soot Precursors during Low-Temperature Combustion of a n-Butanol鈥揇iesel Blend

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• 作者：Xiaorong Zhou ; Mengtian Song ; Haozhong Huang ; Ruzhi Yang ; Mingxia Wang ; Jiaxing Sheng
• 刊名：Energy & Fuels
• 出版年：2014
• 出版时间：November 20, 2014
• 年：2014
• 卷：28
• 期：11
• 页码：7149-7158
• 全文大小：651K
• ISSN：1520-5029

文摘

To study the soot precursor emission characteristics of a n-butanol鈥揹iesel blend during low-temperature combustion (LTC), a model of n-heptane, n-butanol, polycyclic aromatic hydrocarbons (PAHs), and toluene was chosen. Computational fluid dynamics (CFD) software was used to establish a three-dimenisonal (3D) numerical model and to couple it with the chemical kinetics mechanism. The factors studied on soot precursor production were n-butanol blending ratio, exhaust gas recirculation (EGR) rate, injection timing, and intake pressure. The results showed that the formation of four types of soot precursors benzene (A₁), naphthalene (A₂), phenanthrene (A₃), and pyrene (A₄) was delayed and the final amount of precursor produced decreased with increasing the n-butanol blending ratio. The delay in formation of these precursors and the reactions mostly occurred during the premixed combustion stage and with increasing the EGR rate. The final amount of A₁ produced increased with the EGR rate; however, those of A₂, A₃, and A₄ showed a decreasing trend after an initial increase, and the EGR rate corresponding to the peak decreased with increasing the n-butanol blend ratio. The final amounts of A₂, A₃, and A₄ produced increased with increasing the intake pressure. Soot precursors A₁, A₂, A₃, and A₄ formed in advance during the injection timing advancing with the final amounts of A₁ and A₃ produced were less. The final amounts of A₂, and A₄ produced showed a decreasing trend after an initial increase.