In this paper, an approach for the optimization of the porous media burner by changing the coefficients of porosity variation equations and the length of the preheating zone and divergence angle as design variables is presented. For this purpose, a two-dimensional axisymmetric numerical model for premixed methane-air combustion in porous media has been developed and multi-step mechanisms have been used. This model solves the continuity equation, momentum equations, the solid and gas phase energy and the chemical species transport equations by using the finite volume method. The pressure and velocity have been decoupled with the SIMPLE algorithm. The purposes of this paper are to determine the design variables so that NO production is at its lowest level or be less than an acceptable certain amount, and the burner temperature to be at its highest level. The goal of multi-objective optimization is to find a set of possible solutions. The results showed that by decreasing the porosity along with the burner, the NO emission will be at its lowest level, and if the porosity is at its highest along with the burner and the length of the preheating zone is decreased the temperature increases rapidly.

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