AbstractIn this study mixed convection heat transfer in ahomogeneous porousduct of square cross section in ahorizontalorientation is examined. Results from a generalizedForchheimermodel are compared with that from theDarcymodel. The heat transfer rate and the flow behavior depend on the following parameters: Grashof number, Gr =Q'gβKa/kv2, an axial flow pressure drop parameter, ζ =(aK/vμ)dp'/dz', an inertial parameter ξ =mK/a, appearing in theForccheimermodel and the Prandtl number, Pr =Cpμ/k.In theDarcylimit, ξ → 0, the role of the axial flow parameter, λ is reduced to a mere scale factor and the flow behavior is determined by a single parameter, λ = Gr · Pr. Both theDarcyand theForchheimermodels exhibit dual solutions and a hysteresis behavior over a certain range of Gr. Such parametric dependence can be used as an additional tool along with carefully designed experiments to determine the importance of inertial and Prandtl number effects on convective heat transfer in po