Double-Diffusive Natural and Mixed Convection of Binary Nanofluids in Porous Cavities

In this contribution, double-diffusive natural and mixed convection of nanofluids in porous cavities are simulated for cases wherein the base fluid is itself a binary mixture (i.e., salty water). To this aim, a new mathematical model based on the Buongiorno's two-phase model is proposed. The current model incorporates thermophysical properties of a solid matrix, nanoparticles, salt, and water in the governing parameters. The resulting equations are solved using the finite volume approach and the outcomes are successfully validated against previous works. Simulation results are presented and discussed for several cases with the solid matrix being aluminum foam or glass balls and the nanoparticles being Ag, Al2O3, carbon nanotubes (CNT), Co, Cu, CuO, Fe3O4, MgO, TiO2, or ZnO. Inspection of the results in the natural and mixed convection environments demonstrates that CuO−salty water nanofluid leads to the highest heat and mass transfer rates. Moreover, it is found that with replacement of glass balls with aluminum foam, the flow strength rises but the heat transfer rate deteriorates.