EFFECT OF EXTERNAL MAGNETIC FIELD ON NATURAL CONVECTION IN A CUBICAL CAVITY FILLED WITH NANO PARTICLE SUSPENSION.
This paper reports experimental investigation of Natural Convection of non-magnetic electrically conducting
nano-suspension Multi Wall Carbon Nano Tube (MWCNT) and electrically non-conducting Silica nanoparticle suspension, in presence of magnetic field in a differentially heated cubicle cavity with two opposite vertical sides at different constant temperature.The main aim of this experimental investigation is to study the effect of Lorentz force on the heat transfer characteristics of nano-particle suspension, which arises due to motion of nano-particles in applied magnetic field. A comparison between two different particles with different
electrical properties is done to establish the effect of Lorentz force on the nano-particles and the effect on heat
transfer because of interaction between nano-particles and magnetic field. Experiments are done in a cubicle cavity of 25mm side whose one vertical face is maintained at higher temperature by an electrical heater and other opposite vertical face is maintained at lower temperature using cold bath. The results are compared for 2.5 × 106 to 1 × 107 Rayleigh number range, and different magnetic field strength from 0.00 Tesla to 0.30 Tesla in two different perpendicular directions, to study the effect of strength and direction respectively. A suppression in Nusselt number is observed with increase in magnetic field strength, the suppression is more when the magnetic field lines are perpendicular to the convective flow in MWCNT nano-particle suspension. In presence of magnetic field no suppression is observed in case of silica nano-particle suspension .