Abstract:Catalytic combustion of hydrogen and air mixture inside a micro-tube was numerically investigated by using the commercial CFD code Fluent, coupled with the chemical reaction dynamics subroutine Chemkin. Combustion characteristics for different reaction models and the influence of conducting wall, wall materials(Pt, Si and Al) , inlet velocity, and equivalent ratio of hydrogen/air mixture on surface catalytic combustion reaction were discussed. The computational results show that the surface catalytic combustion restrains the gas phase combustion. The conducting wall in micro-tube preheats the inlet mixture by axial heat transfer. The existence of conducting wall will help to reach full reaction in the microtube. As the inlet velocity increases, both the existence of the surface catalytic combustion and the gas phase combustion become the limiting factors on combustion. Wall material and equivalence ratio of hydrogen/air mixture have important influence on catalytic combustion of hydrogen. Some theoretical evidences are provided for the application of catalytic combustion to micro-electromechanical system and for the extension of the combustion limits.