COMBUSTION AND HEAT-TRANSFER IN MODEL 2-DIMENSIONAL POROUS BURNERS

A two-dimensional model of two simple porous burner geometries is deve loped to analyze the influence of multidimensionality on flames within pore scale structures. The first geometry simulates a honeycomb burne r, in which a ceramic is penetrated by many small, straight, nonconnec ting passages. The second geometry consists of many small parallel pla tes aligned with the flow direction. The Monte Carlo method is employe d to calculate the viewfactors for radiation heat exchange in the seco nd geometry. This model compares well with experiments on burning rate s, operating ranges, and radiation output. Heat losses from the burner are found to reduce the burning rare. The flame is shown to be highly two-dimensional, and limitations of one-dimensional models are discus sed. The effects of the material properties on the peak burning rate i n these model porous media are examined. Variations in the flame on le ngth scales smaller than the pore size are also present and are discus sed and quantified. (C) 1998 by The Combustion Institute