Numerical Modeling of Wall Effects in Lean Combustion

Better understanding of combustion near walls has a §significant interest in lean combustion using large §excess of air, for example in the internal §combustion engine concept Homogeneous Charge §Combustion Ignition (HCCI). In this work numerical §simulations have been conducted to study different §aspects of wall effects in the combustion of lean, §premixed, hydrogen and methane fuel/air mixtures. §The simulations have been performed with the program §CRESLAF, a part of the CHEMKIN software. The wall §effects must be analyzed with respect to the §complicated nature of the combustion process. I the §near wall boundary layer, transport of momentum, §heat and mass are done in a manner that may affect §the hundreds of elementary chemical reaction steps. §In addition, the wall may be chemically active and §lead to termination of radical chains, or through §catalytic reactions that may emit products from the §wall and retard the homogeneous reactions. The §results presented in this work may be used by §designers of combustors and microchannel §reactors,where calculations cannot give accurate §results unless the effects of the walls are §accounted for.