Simulation of CuO-water nanofluid natural convection in a U-shaped enclosure with a T-shaped baffle

The effect of aspect ratio and baffle shape on natural convection patterns in a U-shaped cavity filled with CuO water-based nanofluid is examined in detail, with a T-shaped baffle attached to the cold wall. To solve the coupled continuity, momentum, and energy equations, a finite volume method is used, and the pressure–velocity coupling is iteratively solved with the SIMPLE algorithm. The study investigates the impact of Rayleigh number (10 4 –10 6 ), cavity aspect ratio (Ar = 0.4, 0.6), and nanoparticle volume fraction (0 ≤ ϕ ≤ 0.05) on flow pattern and heat transfer features. The results are presented graphically in the form of streamlines, isotherms, mean, and local Nusselt numbers. It is observed that the mean Nusselt number increases with an increase in Rayleigh number, nanoparticle volume fraction, and aspect ratio, resulting in an improvement in heat transfer. The T-shaped baffle enhances heat transfer compared to other baffles. Though changing the aspect ratio (0.4 ≤ Ar ≤ 0.6) does not alter the flow pattern, an increase in Ar leads to an enhancement in the heat transfer rate.