扩散过滤燃烧火焰特性

Flame characteristics for diffusion filtration combustion

扩散过滤燃烧是新的燃烧技术,具有扩散燃烧和预混过滤燃烧的某些特性。通过二维双温模型,使用单步总包反应,数值研究氮气稀释的甲烷和氧气同轴同平板扩散过滤燃烧特性。模型中考虑热弥散和组分弥散效应。研究小球直径、气体混合物速度和甲烷质量分数对火焰高度和火焰形态的影响。结果表明,与预混过滤燃烧不同,气体和固体高温区存在于燃烧器的不同位置;而在高温区域之外,气体和多孔介质固体的温差很小。当填充床小球直径从6.66mm减小到2.02mm,火焰高度从0.048m增大到0.12m。增大混合物速度,甲烷的质量分数导致火焰变宽,火焰高度增大。数值模型的有效性得到了实验验证。

Diffusion filtration combustion is a new combustion technology,which combines some characteristics of diffusion combustion and premixed filtration combustion.A numerical study of diffusion filtration flame characteristics in a nitrogen diluted CH4＋N2/O2co-flow plane-parallel is conducted using a two-dimensional two-temperature model with a simple reaction rate mechanism.Both thermal and species dispersion effects are taken into account.The effects of pellet diameter（d）,gas mixture velocity（ug） and mass fraction of CH4（YCH4）,etc.on the flame shape and flame height are investigated.Results show that high gas and solid temperature zones exist at different locations compared to the premixed filtration combustion,and that in the area aside of the high temperature zone the differences between the gas and porous solid temperatures are very small.Flame height increases from 0.048mto 0.12mas ddecreases from 6.66 mm to 2.02 mm.Increases in ugand YCH4reduce the flame width and flame height.The calculated result is verified by experimental data.