Rayleigh-Benard Convection of Carbopol Yield Stress Fe3O4 Nanofluids Under Magnetic Field: An Experimental Investigation and ANN Modelling

This study presents a comprehensive experimental investigation aimed at elucidating the influence of magnetic fields, nanoparticle concentration, and the presence of polymer on Rayleigh-Benard convection in yield stress nanofluids. The test fluid comprises Ultrez 30 polymeric powder and Iron oxide nanoparticles. Herschel-Bulkley's model is applied to capture the rheological behaviour. The concentration of both Ultrez 30 polymeric gel and Iron oxide nanoparticles varies from 0.05 % to 0.10 %. The in-house developed experimental set-up is exposed to the magnetic field in the 0 mT to 100 mT range. Without a magnetic field, heat transfer increases with the elevation of nanoparticle fraction in the fluid. However, in the presence of a magnetic field, the convection effect weakens as the nanoparticle concentration rises. Furthermore, an optimised artificial neural network (ANN) model featuring a single hidden layer with nine hidden neurons is presented to predict the Nusselt number.