In this study, the Lattice Boltzmann Method (LBM) is employed in order to examine the fluid flow and forced convection heat transfer inside a two-dimensional horizontal channel with and without obstacles. In order to enhance the heat and thermal energy transfer within the channel, different obstacle arrangements are posed to the flow field and heat transfer with the purpose of studying their sensitivity to these changes. The results indicate that, when the value of the Reynolds number is maximum, the maximum average Nusselt numbers happens on the lower wall (Case 4). The paper extends the topic to the use of nanofluids to introduce a possibility to enhancement of the heat transfer in the channel with an array of the obstacles with forced convection. For this purpose, the AgMgO/water micropolar hybrid nanofluid is used, and the volume fraction of the nanoparticle (50% Ag and 50% MgO by volume) is set between 0 and 0.02. The results showed that, when the hybrid nanofluid is used instead of a typical nanofluid, the rate of the heat transfer inside the channel increases, especially for the high values of the Reynolds number, and the volume fraction of the nanoparticles. Increasing the volume fraction of the nanoparticles increase the local Nusselt number ( 1.17-fold). It is shown that the type of obstacle arrangement and the specific nanofluid can exerts significant effects on the characteristics of the flow field and heat transfer in the channel. This study provides a platform for using the LBM to examine fluid flow through discrete obstacles in offset positions.

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