低热值燃气往复多孔介质燃烧特性

为了研究低热值预混燃气（当量比<0.4）在往复式多孔介质燃烧器中的燃烧特性,建立两端布置蓄热段的往复多孔介质燃烧试验台,研究温度波动、轴向温度分布及燃烧极限的特性.结果表明,低热值预混燃气温度波动特性与火焰面位置有直接关系,两端布置蓄热段能够减小泡沫陶瓷多孔介质温度波动幅度.随着当量比的降低,轴向温度分布形状从“马鞍形”、“梯形”、“椭圆形”,变化到系统达到燃烧极限时形成的“三角形”分布.加入蓄热小球使高温段平均温度升高、排烟温度降低.燃烧极限与系统半周期、空截面流速及热负荷密切相关.系统能够达到的最低燃烧当量比为0.1.

Combustion characteristics of low calorific gas in reciprocal flow porous media burner

An experimental system with regenerative sections at both ends was conducted to analyze the combustion characteristics of low calorific premixed gases （equivalence ratio<0.4）in a reciprocal flow porous media combustor. Temperature fluctuation, axial temperature distribution and flammability limits were investigated. Results show that the flame position directly influences the temperature fluctuation of exhaust gases; Adding regenerative sections leads to the reduction of temperature fluctuation amplitude in ceramic foam; the shape of axial temperature distribution has continuous changes, from saddle-shaped, ladder-shaped, oval-shaped to triangle-shaped when the system reaches flammability limit as the equivalence ratio decreases. The average temperature of high temperature zone rises and the temperature of exhaust gases falls by adding the regenerative sections. The flammability limit is closely related to half period, inlet velocity and heat load. The flammability limit can be extended to the low equivalence ratio of 0.1．