CFD Study and Regression Analysis of the MHD Mixed Convection of CNT-Water Nanofluid in a Vented Rounded Edge Rectangular Cavity Having Inner Vertical Rod Bundle

This current work provides a comprehensive Computational Fluid Dynamics (CFD) investigation of three-dimensional magnetohydrodynamic (MHD) mixed convection of carbon nanotube (CNT)-water nanofluid within a vented rectangular cavity featuring an internal vertical rod bundle with circular, square, and triangular cross-sections. The finite element method (FEM) was used to investigate the effects of key parameters, including the Richardson number (0.01 <= Ri <= 10), Hartmann number (0 <= Ha <= 100), and CNT nanoparticle concentration (0 <= phi <= 0.045), in relation to fluid flow and heat transfer performance. The CNT nanoparticle incorporation increases the nanofluid's heat transfer capacity by up to 22%, with the highest average Nusselt number (Nuav) achieved with circular rods at phi = 0.045, which corresponds to the higher convective heat transfer efficiency. The magnetic field further stabilizes the flow by reducing thermal convection irregularities, with a 15% improvement in temperature distribution uniformity when Ha = 100. The investigation's outcomes reveal that due to their smoother geometries, the circular rods exhibit better thermal exchange rates compared to square and triangular rods. Moreover, a polynomial regression model is used to correlate the governing parameters and heat transfer rates, and it achieves a high R2 of 0.964. These findings highlight the potential of CNT-water nanofluid and magnetic field applications for thermal management optimization in various engineering systems.