Flow of nanofluid and hybrid fluid in porous channels: Experimental and numerical approach

Heat enhancement and heat storage are becoming important engineering topics related to renewable energy. Different fluid classes have been proposed, and various types of phase change materials have been used for energy storage. Nanofluids, which consist of nano metallic particles in liquids such as water, have been receiving a lot of attention recently. Some exaggerations regarding the conductivity of these fluids lead researchers to conduct further investigations on the physical properties of this new class of fluid. In this paper, an attempt was made to conduct a detailed experiment aiming to investigate the quality of heat enhancement one should expect from this fluid class. The experiment, consisting of the forced convection of a nanofluid composed of Al2O3 in water, demonstrated that heat enhancement is obtainable in the 6% range, regardless of the concentration of nanoparticles in the water. Computational fluid dynamics were in good agreement with the experimental data. The studies revealed that there is an optimum nanofluid concentration which achieves the highest heat transfer enhancement. As the concentration of nanoparticles increases beyond the optimum concentration, there is no longer a significant enhancement in heat transfer. Besides, the pressure drop increases along with increases in the nanoparticle concentration. A new hybrid fluid composed of aluminum oxide and copper oxide in water revealed further enhancement but a further increase in the pressure drop. It is therefore concluded that the hybrid fluid is an alternate choice if one needs to extract heat at the expense of the pressure drop.