Experimental Investigation of Filtration Combustion Instability with Lean Premixed Hydrogen/Air in a Packed Bed

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• 作者：Yongfang Xia ; Junrui Shi ; Benwen Li ; Chunmei Yu ; Youning Xu ; Zhijia Xue
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：August 16, 2012
• 年：2012
• 卷：26
• 期：8
• 页码：4749-4755
• 全文大小：442K
• 年卷期：v.26,no.8(August 16, 2012)
• ISSN：1520-5029

文摘

Investigation of filtration combustion instability of lean premixed hydrogen/air mixtures in a packed bed is conducted experimentally. The evolution of flame front instabilities, including inclination, deformity, and hot spots, are observed in various experimental cases. When the flame front has an initial inclinational angle (伪), the inclination instability will successively develop in the experiment without the emergence of a hot spot. Meanwhile, a peculiar instability of flame front deformity is observed, and it cannot be found in the repeated experiments. Hereby, the flame front perturbation, caused by the random structure of packed bed, should be considered. The hot-spot instability is observed under different hydrogen concentrations and filtration velocities. During the propagating of flame front, the cellular structure, which consists of hot spots and appears on the upstream side of the superadiabatic wave, strongly dominates the stability of main combustion wave. When the main wave disappears, the cellular structure will asymmetrically stand within the combustor. Additionally, it is identified that the hot-spot instability can easily occur within a low-porosity packed bed. Furthermore, it is found that the propagation velocity of main wave will decrease when the cellular structure appears. The major cause may be that the hydrogen is partially burned in the cellular structure, and this will lead to the reduction of the main wave temperature and, accordingly, the depression of combustion wave propagation velocity.