The effect of a magnetic field on the natural convection of a paramagnetic fluid is numerically studied between vertical heated parallel plates. The magnetic field is presumed by the Ampere’s law from electric wires. The heat and fluid flow is simultaneously solved by the lattice Boltzmann method (LBM). For the evaluation of the natural convection by the LBM, a validation is firstly carried out in a square cavity in the absence of the magnetic field. It is confirmed that single-relaxation-time LBM has a comparable validity to the reference data. For the natural convection between the parallel plates under the magnetic field, the magnetothermal force is induced as a repelling force from the magnet. This is because the hotter fluid receives weaker magnetic force than the fluid at reference temperature. This magnetothermal force locally affects the heat and fluid flow near the walls, resulting in enhancement and suppression of the natural convection. In this study, the effect of the magnetic field by electric wires is investigated for two cases; facing different magnetic poles (N–S) and same poles (N–N). It is found that, when the magnetic field is presumed by electric wires, the magnetothermal force becomes similar in both cases, resulting in the similar effects on the heat and fluid flow. This is because that the force in the vicinity of the wire is dominant on the effects.
International Journal of Advances in Engineering Sciences and Applied Mathematics – Springer Journals
Published: Jun 2, 2018