Study On Heat Transfer Characteristics Of Micro-Combustor Filled With Porous Media

In this paper,H2/Air premixed gas in a micro-combustor filled with porous media was simulated by using FLUENT.The preheat zone of porous media,the reaction zone and the wall preheat zone were defined,the recirculation efficiency and heat loss efficiency in the reaction zone were also defined.The effect of thermal conductivity of porous media,porosity,thermal conductivity of wall,equivalence ratio and inlet flow velocity on combustion temperature,heat recirculation of porous media and wall in the micro-combustor were analyzed quantitatively by parametric research method.The numerical simulation results show that thermal conductivity of porous media is an important factor to affect the combustion temperature,heat recirculation of porous media and wall.With the increase of thermal conductivity of porous media,ηg-shr and ηcondhr get increased,ηradhr,ηg-whr and ηcondw get decreased,the combustion temperature also decreased.Porosity of porous media can affect the combustion temperature significantly,reducing porosity of porous media can enhance the convective heat transfer between gas and porous media,ηg-shr and ηcondhr get increased,ηg-whr and ηcondw get decreased,Qoverallhr/Qoverallhr get increased significantly.With the increase of thermal conductivity of wall,ηg-shr get decreased,ηg-whr get increased.The recirculation efficiency are negatively correlated with equivalence ratio.With the increase of inlet flow velocity,ηg-shr and ηcondhr get up and then get down,ηg-whr get up and then get flatten.These research results can provide some guidance for the design of micro-combustor filled with porous media.