Experimental results are presented on natural convection heat transfer from a horizontal cylinder to potassium under a horizontal magnetic field. A cylindrical heater of 7.8 mm in outer diameter and 50 mm in effective heating length is immersed horizontally in a potassium pool. The wall and liquid temperature are measured around the cylinder for a heat flux up to 7.2 × 105 W/m2 and for a magnetic flux density up to 0.7 T. The heat transfer coefficient in the absence of a magnetic field is well correlated considering the heat conduction effect. Various temperature fluctuations are observed in the presence of the magnetic field. The convection states are classified into four regions according to the temperature fluctuation patterns and the temperature distributions, and are shown in maps based on the magnetic flux density and the heat flux. It is shown that natural convection is stable for a higher heat flux in the presence of a magnetic field than it is without the magnetic field. However, the unstable regions are much more unstable with the magnetic field than without. The heat transfer is suppressed in the stable region but is enhanced in the unstable regions by the presence of the magnetic field.
Energy transport and magnetic stochasticity at the edge of a plasma in RFP configuration