随机填充型多孔介质的表面燃烧现象

Surface Combustion Phenomenon of the Randomly Packed Structures

为研究随机填充型多孔介质尾流区域的流动状态和预混气体在其表面燃烧的火焰特性,设计一种新型随机填充结构尾流燃烧器以及可视化实验装置,分析入口流量对填充型多孔介质表面流场的影响,以及甲烷/空气预混气体在其表面燃烧的火焰形态和排放特性。结果表明:冷态流场整体平均空气流量增大20 L/min,流场平均速度增大,涡量和应变率随之增大50%左右;靠近填充床表面区域平均轴向速度高且波动幅度大,远离填充床区域的速度波动幅度减小且趋于均匀分布;当量比对速度分布影响较大,但其对火焰传播的影响相对较小;烟气中CO的含量在空气流量50 L/min、当量比0.91时达到最低值。本文的研究结果对于开发多孔介质表面燃烧器有一定的指导作用。

To study the flow state in the wake region of a randomly packed structure and the flame characteristics of premixed gas burning on its surface,a new randomly packed structure wake burner and a visual experimental device were designed.The influence of inlet flow rate on the surface flow field of randomly packed structure and the combustion and emission characteristics of methane/air premixed gas on its surface were studied.The results show that the air flow increases by 20 L/min,the overall average velocity of the unreacted flow field increases,and the vorticity and strain rate increase by about 50%.The average axial velocity near the packed bed surface is high and the fluctuation is violent,while the fluctuation far from the packed bed reduce and tends to be uniform.The effect of equivalent ratio on velocity distribution is significant,but its effect on flame propagation is relatively attenuate.Under experimental conditions.The content of CO in flue gas reaches the lowest value when the air flow rate is 50 L/min and the equivalent ra-tio is 0.91.The experimental results have a certain guiding role for the development of porous media surface burner.