Magnetic field impact on free convection of a nanofluid in a cavity with corrugated walls and having V-shaped baffles

Abstract

In this study, an investigation of heat transfer by free convection in a wavy-walled cavity loaded with Al2O3–water nanofluid and subjected to a magnetic field was developed. In lower wall of this cavity baffles are installed. The different conservation equations were solved via Ansys-Fluent software by applying the finite volume technique and the buoyancy forces were expressed by Boussinesq approximation. This investigation gives explanations on the impact of the different factors on heat exchange and nanofluid movement in the chosen geometry, namely, Rayleigh and Hartmann numbers, volume fraction, and presence of baffles which is considered the novelty of this work. Results found illustrate that heat exchange is enhanced by intensification of Rayleigh number and addition of nanoparticles, due to development of a significant temperature gradient and the improved characteristics of nanofluids while the growth of Hartmann number reduces heat exchange owing to the magnetic field action on free convection. Depending on the configuration studied, the installation of the baffles can sometimes localizes the flow in an area of the enclosure and reduces heat transmission which is the case of this study. Finally, correlations were proposed for Nusselt number to get an idea on heat exchange rate and which are rarely given in this type of studies. These results can help in the design of certain energy systems.