多孔介质微小燃烧器的传热特性分析

Heat Transfer Characteristics of Micro-Combustors Filled with Porous Media

采用计算流体力学软件Fluent,对H2/空气预混气在全填充多孔介质平板微燃烧器内的燃烧过程进行数值模拟.研究了多孔介质导热系数、壁面导热系数、当量比、孔隙率对微燃烧器回热循环的影响规律.模拟结果表明:预热区对流回热效率、多孔介质导热效率与多孔介质导热系数呈正相关趋势;壁面导热系数增大会使预热区对流回热效率下降,壁面对流回热效率上升;预热区对流回热效率、壁面对流回热效率与当量比呈负相关趋势;多孔介质孔隙率是影响回热效率的重要因素,随着孔隙率的增大,预热区对流回热效率下降,壁面对流回热效率上升.

By using the computational fluid dynamics software Fluent,the combustion of hydrogen/air premixed gas was simulated in a planar micro-combustor fully filled with porous media.The effects of the thermal conductivity,porosity,thermal conductivity of wall,and equivalence ratio of porous media on the heat recirculation of micro-combustor were studied.The simulation results show that the preheat convective recirculation efficiency and porous media conduction efficiency are positively correlated with the thermal conductivity of porous media.Increasing the thermal conductivity of wall will decrease the preheat convective recirculation efficiency and increase convective recirculation efficiency of wall.The preheat convective recirculation efficiency and convective recirculation efficiency of wall are negatively correlated with equivalence ratio.Porosity of porous media is also an important factor in affecting recirculation efficiency.With the increase of porosity,the preheat convective recirculation efficiency will decrease while the convective recirculation efficiency of wall will increase.