Numerical study of molten salt flow and heat transfer in a pipe applied non-uniform magnetic field

Abstract

Based on the magnetohydrodynamics model, this study numerically investigated the influence of a transverse non-uniform magnetic field on the flow and heat transfer characteristics of molten salt in a conductive pipe. The magnetic field was constructed with three sections including gradient and uniform regions, which was fitting to real application of the magnetic field. The flow and heat transfer of molten salt were studied within the ranges of 0 ≤ Ha ≤ 200 and 3000 ≤ Re ≤ 12 000. The results indicated that variation of magnetic field had significant effects on the flow velocity, turbulent intensity, and Joule heat, thus influencing the temperature and the Nusselt number of molten salt. Although the flow in core region was suppressed by the magnetic field, the flow velocity was enhanced and turbulence was reduced near the pipe wall, which was shown obviously different within three regions of the magnetic field. An interesting phenomenon of local heat transfer enhancement with increasing magnetic intensity was observed in the first section of the magnetic field, which was from the complex effects of flow velocity and turbulence. In addition, the Joule heat was calculated and analyzed to determine its influence on heat transfer under the magnetic field. A detailed analyzation of magnetic fluid flow in this study was provided to hopefully promote the molten salt in real application of flow and heat transfer.