Numerical Study of the Free Convection of a Hybrid Nano-Fluid Filling a Three-Dimensional Cavity Exposed to a Horizontal Magnetic Field

This paper presents a numerical study on natural convection and heat transfer using a hybrid nanofluid within a three-dimensional cavity under the influence of a magnetic field. The primary objective of this research is to analyze how various magnetic field conditions affect the thermal performance of the hybrid nanofluid, particularly in terms of heat transfer and fluid motion. Specific objectives include evaluating the effects of the Rayleigh number, nanoparticle volume fraction, and Hartmann number on the dynamic and thermal fields, as well as the overall heat transfer efficiency. The transport equations were discretized using the finite volume method, and the SIMPLEC algorithm was employed to couple the velocity and pressure fields. The vertical walls of the cavity were subjected to different heating conditions, while the horizontal walls were assumed to be adiabatic. The results, presented in the form of isotherms, streamlines, and Nusselt numbers, indicate that at low Hartmann numbers, heat transfer is enhanced due to better fluid circulation and more effective thermal dissipation, particularly with increasing Rayleigh numbers and nanoparticle volume fractions. However, at higher Hartmann numbers, the magnetic field’s influence becomes dominant, significantly reducing heat transfer efficiency. In conclusion, the study shows that the hybrid nanofluid outperforms pure water and simple nanofluids in terms of thermal performance at low magnetic field strengths. However, its effectiveness diminishes as the Hartmann number increases. These findings suggest the need for alternative strategies to improve heat transfer in industrial applications involving strong magnetic fields, such as in particle accelerators or nuclear magnetic resonance (NMR) devices.