ABSTRACT

The premixed combustion of lean methane-air mixture in a structured porous combustor filled with alumina cylinders was experimentally studied. The alumina cylinders with a diameter of 6.5 mm and a height of 19.5 mm were regularly staggered placed in the combustor and the average porosity of the packed bed was approximately 0.43. The characteristics of interest were the temperature distribution, the peak combustion temperature, and the combustion wave propagation velocity. The parameters investigated that affect these characteristics included gas inlet velocity and equivalence ratio. Results indicated that the combustion wave propagation was stable and super-adiabatic combustion phenomena were observed under the test conditions of the equivalence ratios in the range of 0.162–0.324 and inlet velocities in the range of 0.43–0.86 m/s. The lean flammability limit was extended to an equivalence ratio of 0.162 at the inlet velocity of 0.43 m/s. The larger equivalence ratio and inlet velocity can supply more fuel to be sufficient combustion, resulting in the higher peak combustion temperature. The combustion wave propagation velocity was inversely correlated with the equivalence ratio. With increasing inlet velocity, the combustion wave velocity increased. The order of magnitude of the combustion wave velocity was 0.1 mm/s. The pressure drop across the structured porous packed bed was remarkably smaller than that of the random one.

摘要

实验研究了贫甲烷-空气混合物在填充有氧化铝圆柱体的结构化多孔燃烧器中的预混燃烧。直径6.5mm、高19.5mm的氧化铝圆柱体规则交错放置在燃烧室中，填充床的平均孔隙率约为0.43。感兴趣的特征是温度分布、峰值燃烧温度和燃烧波传播速度。研究的影响这些特性的参数包括气体入口速度和当量比。结果表明，当当量比在0.162-0.324范围内，入口速度在0.43-0.86 m/s范围内的试验条件下，燃烧波传播稳定，观察到超绝热燃烧现象。在入口速度为 0.43 m/s 时，贫燃极限扩展到当量比 0.162。较大的当量比和入口速度可以提供更多的燃料以进行充分燃烧，从而导致更高的峰值燃烧温度。燃烧波传播速度与当量比成反比。随着入口速度的增加，燃烧波速度增加。燃烧波速度的数量级为0.1mm/s。结构化多孔填充床的压降明显小于随机床的压降。燃烧波传播速度与当量比成反比。随着入口速度的增加，燃烧波速度增加。燃烧波速度的数量级为0.1mm/s。结构化多孔填充床的压降明显小于随机床的压降。燃烧波传播速度与当量比成反比。随着入口速度的增加，燃烧波速度增加。燃烧波速度的数量级为0.1mm/s。结构化多孔填充床的压降明显小于随机床的压降。