Natural convective flow of non-isothermal hybrid nanofluid inside the cavity with the influence of a heated fin and non-linear thermal radiation: Second law analysis

This study computationally analyzed the effects of heated fin, non-linear thermal radiation, and volume fraction of nanoparticles (Ag and Cu) with base fluid Ethylene Glycol for natural convective flow of hybrid nanofluid inside the cavity. The distraction of energy transport is also calculated and analyzed using the concept of second law of thermodynamics, and estimated the dominant irreversibility due to flow friction/heat transfer in terms of Bejan number. The two-dimensional trajectory of heat flow inside the enclosure is also calculated by utilizing the concept of Bejan heat lines. The Galerkin finite element technique has been used to convert the governing system of PDEs into nonlinear-algebraic equations and then the Newton-Raphson technique is utilized to solve it. The obtained results show that in the absence of the heated fin (at h = 0), the circulations of heatlines have not appeared, but in the case of the heated fin, the bowls of heatlines are formed indicating the enhanced buoyancy-driven flow. Consequently due to enhanced buoyancy-driven flow (by increasing the height of the heated fin from 0 to 0.4) increase in the fluid velocity is observed by 42% and the heat transfer rate increased by 57%. The increasing trend of fluid velocity and heat transfer profiles is noted by increases in the concentration of solid nanoparticles, but reverse behavior in entropy generation is observed.