Effect of vortex promoter shape on heat transfer in MHD duct flow with axial magnetic field

Abstract The heat transfer from the side-wall of a duct through which an electrically conducting fluid flows within a strong transverse magnetic field is numerically investigated using high-resolution numerical simulation. Parameter ranges considered are 0 ≤ H a ≤ 2400 and 100 ≤ R e ≤ 3000 for a constant blockage ratio of 1 / 4 . The gain in the heat transfer using obstacles of different geometric shapes are compared. For H a = 320 , a maximum heat transfer enhancement of 78 % is obtained when using the square cylinder at a modes R e = 1000 , while the triangular cylinder outperformed the various other vortex promoter geometries at Re = 2000 yielding a 75% improvement.. However, at a higher Hartmann number of H a = 2400 , a maximum heat transfer augmentation of 16 % and 40 % is obtained for the triangular cylinder at R e = 1000 and 2000, respectively. This suggests that for a duct flow under the influence of a strong magnetic field, the triangular obstacle is a superior heat transfer promoter geometry compared to the square or circular cylinders. A further net power analysis reveals that the heat transfer enhancement dominates over the pumping power to produce net benefits for even a modest heat transfer enhancement.