Heat transfer in MHD laminar flow through a rectangular channel in the plasma facing components of fusion reactors

Convective heat transfer in MHD laminar flow through a square duct in the plasma facing components (PFCs) of fusion reactors is analyzed numerically to investigate the effects of a transverse magnetic field and the nonuniformity of surface heat flux. As in the case of non-MHD laminar flow, analyzed earlier, the corners of the plasma facing (PF) side are possible hot-spot areas; the presence of a transverse magnetic field does not alleviate this situation to any significant degree. The nonuniformity of surface heat flux nearly cancels this increase of Nu at the PF side. At Hartmann number (Ha) of 40, Nu at the center increases from 6.9 to 23, but at the corner from 2.2 to 3.2 only with uniform heat flux. But, as the extent of nonuniformity of surface heat flux increases, Nu at the center decreases rapidly. This effect, however, saturates rapidly with the increase of the nonuniformity of heat flux. The increase of Nu with Ha is very small for large nonuniformity of the heat flux. Under this condition, Nu at the center of the plasma facing side, is 2.8 at Ha=O, 3.02 at Ha=16 and 3.4 at Ha=400. At the corner of the PF side, the corresponding values of Nu are 2.65, 2.88, and 3.0, respectively. The effect of Ha on entry length is small for highly nonuniform heat flux