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Abstract
In the present work, we have numerically investigated the effects of the rotation on the hydrodynamic and thermal fields inside a germanium float zone under microgravity conditions. The melting liquid is assumed viscous and incompressible, with constant physical properties; both the flow and the thermal field are considered axisymmetric. The system of governing equations subjected to appropriate boundary conditions has been successfully solved by using the modified SIMPLE method. Numerical results have shown that the flow structure may become rather complex with the presence of the imposed rotation. An exhaustive study on the effects of rotation has been carried out for several rotational configurations: one end rotating and the other end fixed, co-rotation of both ends, and counterrotation. In general, it has been found that rotation produces beneficial effects in the reduction of the Marangpni convection flow. The co-rotation from both ends has been found to be the most efficient means to obtain this objective. On the other hand, exact counterrotation, although it can be used to reduce the intensity of the thermocapillary flow, is not recommended because it may conduct to a nonsymmetric ( i.e., unstable) flow structure within the zone.