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The purpose of this study is analysis of the natural convection and entropy production in a two-dimensional section of the considered heat exchanger. For this purpose, the lattice Boltzmann method which is equipped with Bhatnagar–Gross–Krook model is used. This model proposes a significant accurate prediction for thermal and hydro-dynamical behaviors over free convection phenomenon. The heat exchanger is filled with Fe₂O₃-water nanofluid. To improve the accuracy of prediction, it is neglected to use the theoretical models for properties of nanofluid. At this end, some experimental observations are conducted, and the required rheological and thermal properties of nanofluid are measured based on laboratory work..

The present work focuses on the influence of different factors on the thermal behaviors and entropy production of a heat exchanger. The heat exchanger is consisted by an inner tube, an outer tube and some fins which are implanted at the surface of inner tube.

The effects of various factors like structure of inner fins, nanoparticle concentration and Rayleigh number over the heat transfer rate, local and volumetric entropy production, Bejan number, flow configuration and temperature distributions are provided.

The originality of this work is using a new-developed numerical method for treating natural convection and experimental measurements for thermal and rheological properties of nanofluid.

The purpose of the present work is to investigate the hydrodynamic and thermal performance of a thermal storage based on the numerical and experimental approaches using the lattice Boltzmann method and the experimental observation on the thermo-physical properties of the operating fluid.

For this purpose, the Al₂O₃ nanoparticle is added to the lubricant with four nanoparticle concentrations, including 0.1, 0.2, 0.4 and 0.6Vol.%. After preparing the nanolubricant samples, the thermal conductivity and dynamic viscosity of nanolubricant are measured using thermal analyzer and viscometer, respectively. Finally, the extracted data are used in the numerical simulation using provided correlations. In the numerical process, the lattice Boltzmann equations based on Bhatnagar–Gross Krook model are used. Also, some modifications are applied to treat with the complex boundary conditions. In addition, the second law analysis is used based on the local and total views.

Different types of results are reported, including the flow structure, temperature distribution, contours of local entropy generation, value of average Nusselt number, value of entropy generation and value of Bejan number.

The originality of this work is combining a modern numerical methodology with experimental data to simulate the convective flow for an industrial application.