Effect of Viscous Dissipation on Thermogravitational Convection in U-shaped Enclosure Having Corner Baffle(s) Filled with Magnetohybrid Nanofluids

This article presents an investigation into the impact of viscous dissipation on thermogravitational convection within a U-shaped enclosure. The enclosure is filled with a water-based TiO2-CoFe2O4 hybrid-nanofluid, with baffles positioned at two corners of the lower surface. Four geometrical arrangements (Case-I, Case-II, Case-III, and Case-IV) are examined. The aim is to elucidate the intricate interplay between several aspects, including fluid dynamics, heat transfer, and the presence of hybrid nanofluids. The governing equations are examined using a higher-order compact formulation. The formulation is a finite difference compact scheme which is fourth order accurate in space coordinate. This scheme can capture the flow physics in low grids which reduces the computational cost. The reliability of our in-house program is established through rigorous verification procedures, encompassing grid independence tests and comparisons with experimental and theoretical findings from researchers. The novel importance of the work encompasses six key elements: the unique properties of hybrid nanofluids, the geometric arrangement of baffles, the U-shaped enclosure design, the influence of viscous dissipation (0 <= Ec <= 0.03), interactions with magnetic fields, and the utilization of advanced compact computational techniques, across a spectrum of parameters. The findings unveil that viscous dissipation impedes the thermal diffusion, precipitating a decline of thermal performance up to 36.34% in Case-I, 17.83% in Case-II, 15.70% in Case-III, and 5.23% in Case-IV with the upsurge of Eckert value. The mean Nusselt number in variation of magnetic field compared to without magnetic field results discernible increase of 8.53% in Case-II and 9.97% in Case-III. Furthermore, the strategic placement of corner baffles emerges as a pivotal mediator in the interplay of magnetic effect and fluid transportation. Remarkably, across the cases (II, III and IV), a discernible upward trajectory in the Nusselt number ratio is discerned concomitant with the escalation of nanoparticle volume fraction, which augmenting thermal efficacy.