## 1 Introduction  
The heat transfer due to fluid flow is an important factor in problems in industries, such as heat exchangers, the recovery of petroleum resources, fault zones, catalytic reactors, cooling systems, electronic equipment manufacturing, etc. The heat transfer characteristics in the boundary layer are influenced by a number of factors, including flow geometry, the viscosity of a fluid, thermal conductivity, bounding surface characteristics, boundary conditions, flow medium and the orientation and intensity of the applied magnetic field [1; 2; 3]. [PERSON] first proposed that the thermal conductivity of the fluid can be increased by including solid particles in the flow domain [4]. Following [PERSON], extensive research has been conducted to study the heat transfer characteristics of fluid flow in a porous medium. It is beyond the scope of this work to revisit the vast amount of literature on different Newtonian and non-Newtonian fluids' flow within a porous medium. A comprehensive literature on forced/natural convective heat transfer in porous medium can be found in [5; 6]. The introduction of nanofluids by [PERSON] [7] offered new possibilities of heat transfer enhancement, and a number of studies were conducted to study the effects of the thermal properties (mainly thermal conductivity), viscosity and convective heat transfer performance of nanofluids. Experiments performed by [PERSON] et al. [8] and [PERSON] et al. [9] showed that the effective thermal conductivity of nanofluids increases under macroscopically stationary conditions. [PERSON] [10] performed a detailed analysis on convective transport in nanofluids. A comprehensive literature survey on transport and heat transfer characteristics of nanofluids was presented in the review articles of [PERSON] et al. [11] and [PERSON] and [PERSON] [12]. It has been demonstrated that nanofluids can have significantly better heat transfer characteristics than the conventional fluids depending upon the type, size and concentration of nanoparticles and the nanofluids' transport through the porous media. [PERSON] and [PERSON] [13; 14] first studied the effects of porous media, thermophoresis and Brownian motion on the convective heat transfer of nanofluids. [PERSON] and [PERSON] [15] found the numerical solution of the steady-state free convection heat transfer behavior of nanofluids inside a triangular enclosure saturated by a porous media. It was observed that the heat transfer rate increases with the increase in nanoparticle volume concentration at a low Rayleigh number, whereas the opposite trend was observed for a high Rayleigh number. [PERSON] and [PERSON] [16] studied the double-diffusive free convection from a vertical plate to a porous medium saturated with a binary base nanofluid. The influence of the internal heat source on the onset of Darcy-Brinkman convection in a porous layer filled with a nanofluid was presented by [PERSON] et al. [17]. They showed that the porous medium has stabilizing effects on the modeled system. [PERSON] et al. [18] studied the free convection of nanofluids along a vertical plate in porous media. [PERSON] et al. [19] studied numerically the force convective MHDflow of a nanofluid in a channel partially filled with porous media. The steady mixed convection boundary layer flow of nanofluids past a vertical flat plate embedded in porous media was discussed by [PERSON] and [PERSON] [20]. Recently, [PERSON] and [PERSON] [21] presented a detailed study on the flow of three different nanofluids (Cu\(-\)water,Al\({}_{2}\)O\({}_{3}-\)water and TiO\({}_{2}-\)water) in an inclined channel saturated by a porous media. A review article detailing the literature on the convective heat transfer of nanofluids in porous media and some recent investigations on nanofluids models and related topics can be found in [22; 23; 24; 25; 26].