Suppressing Rayleigh–Benard convection in a cube using a strong magnetic field — experimental heat transfer rate measurements and flow visualization

Abstract

The average heat transfer rate of joint gravitational and magnetic convection of a paramagnetic fluid (an 80% mass aqueous solution of glycerol with 0.8 mol/kg concentration of gadolinium nitrate hexahydrate) in a cubic enclosure heated from below and cooled from above is experimentally measured for five different strengths of the magnetic field. The cubic enclosure of 0.032-m sides is placed in the bore of a 5-Tesla super-conducting magnet below the solenoid centre at a position where the magnetic force distribution is relatively uniform. The magnetic field imposed in the vertical direction acts against gravity and the heat transfer rate decreases with the increase of the magnetic induction. Furthermore, steady and transient states flow visualizations are carried out with a 10-Tesla super-conducting magnet to show a stable stratification obtained in the form of magneto-thermal.