填充多孔纤维的微细通道内CH_4/空气火焰的稳燃机理  

Flame Stabilization Mechanisms of CH_4/Air Mixtures in Mesoscale Channels Filled with Fibrous Porous Media

作　　者：向赢 刘毅 范爱武[1] Xiang Ying;Liu Yi;Fan Aiwu(School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学能源与动力工程学院,武汉430074

出　　处：《燃烧科学与技术》2018年第5期439-445,共7页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(51576084)

摘　　要：在微细通道内填充高孔隙率(0.94)、低导热系数(0.3,W/(m·K))的陶瓷纤维能够有效拓宽驻定火焰波发生的速度范围.为了揭示其稳燃机理,本文进行了数值模拟,结果表明:增大纤维导热系数或者减小孔隙率时,驻定火焰出现的速度范围缩小,而且火焰对上游未燃气体的预热量和向下游的散热量都将增大,但是后者明显高于前者.因此,微细通道内填充纤维型多孔介质后驻定火焰范围变宽的根本原因在于其具有很低的导热系数和很高的孔隙率,有效地减少了火焰向下游传递的热量,提高了火焰稳定性.The velocity limits of stationary flame can be effectively expanded by filling ceramic fibers with high porosity（0.94）and low thermal conductivity（0.3,W/（m·K））in mesoscale channels.To reveal the underlying mechanisms,numerical simulation was conducted.The results show that,by increasing the thermal conductivity or decreasing the porosity of ceramic fibers,the velocity range of stationary flames shrinks noticeably. Quantitative analysis demonstrates that the heat recirculation to upstream mixture and the heat transfer downstream are both enhanced,but the latter is more pronounced than the former.In conclusion,the reasons for the stronger flame stability of the mesoscale channel filled with fibrous porous media are the high porosity and low thermal conductivity of ceramic fibers,which can significantly reduce the heat dissipation from the flame to downstream gases.

关 键 词：微燃烧器 纤维型多孔介质 导热系数 孔隙率 驻定火焰 

分 类 号：TK123[动力工程及工程热物理—工程热物理]