Numerical Analysis of Magnetohydrodynamics Mixed Convection and Entropy Generation in a Double Lid-Driven Cavity Using Ternary Hybrid Nanofluids

The present study numerically investigates the effects of a magnetic field on mixed convection flow and entropy generation within a double lid-driven square cavity filled with a hybrid nanofluid. The flow is induced by two isothermally heated semi-circles located on the bottom and left walls of the cavity. The cavity is filled with a ternary composition of hybrid nanofluid (aluminum oxide/silver/copper oxide-water) and is exposed to a uniform magnetic field. The velocity ratio of the moving lids and the radius ratio of the semi-circles are key parameters in the analysis. The study employs the finite volume method and full multigrid acceleration to solve the coupled continuity, momentum, energy, and entropy generation equations, along with the relevant boundary conditions. Key dimensionless parameters considered include the Hartmann number (0 ≤ Ha ≤ 100), Richardson number (0.01 ≤ Ri ≤ 1), hybrid nanofluid volume fraction (3% ≤ ϕ ≤ 12%), internal semi-circle radius ratio (β = 0.5 and 1), and velocity ratio (−2 ≤ λ ≤ 2). Results revealed that the optimal heat transfer is achieved for Ri = 0.04, Ha = 100, ϕ = 0%, β = 1, and λ = 0.5 with 63% enhancement. Moreover, the maximum entropy generation rates are obtained for the same parameters with a rate of 47%, reflecting the complex balance of enhanced heat transfer and associated irreversibility's. Results reveal also that heat transfer and entropy generation are a decreasing function of Hartmann number implying a suppress of fluid motion due to the Lorentz force. This study provides a valuable resource and parametric analysis for researchers and engineers, aiding in the design and optimization of thermal management systems for various industrial applications, including heat exchangers, nuclear reactors, and energy systems.