In this paper the propagation of combustion waves in solid composite energetic material consisting of fuel and highly thermal conductive inert elements is investigated using a one-dimensional model with a single step reaction mechanism. The analysis is focused on the study of the effect of the geometrical configuration of the composite material on flame speed and dynamics. Spatial averaging over directions transverse to the propagation direction is performed in such a way as to retain the multidimensional nature of the problem. It is shown that the regimes of combustion depend on the geometry of the composite. The largest possible flame speed enhancement is attained in cases when the heat fluxes along the structural elements are not disrupted. For each configuration selected, there exists an optimal choice of the geometric parameters that maximizes the flame velocity.