CONVECTIVE HEAT-TRANSFER DUE TO THERMOCAPILLARY CONVECTION WITH A STRONG MAGNETIC-FIELD PARALLEL TO THE FREE-SURFACE

This paper treats the motion and heat transfer in an electrically cond ucting fluid that is bounded by two parallel, isothermal walls, and by a plane free surface. Gradients in the surface tension of the free su rface drive a strong recirculating thermocapillary convection. In the presence of a magnetic field which is parallel to the free surface, th e thermocapillary convection is confined to a thin boundary layer adja cent to the free surface. Only when the Peclet number is at least O(Ha (1/4)), where Ha is the large Hartmann number, is the heat flux enteri ng the free surface redistributed by thermal convection inside the bou ndary layer before entering the quiescent core. This problem is a mode l of the floating-zone growth of semiconductor crystals with a uniform , axial magnetic field. (C) 1997 Elsevier Science Ltd.