Heating of compound samples in monoellipsoidal mirror furnaces Original Research Article

The heating of cylindrical compound samples in monoellipsoidal mirror furnaces is studied. A line-source model for the lamp (instead of a point source) is considered. The irradiation profiles obtained for this lamp model are analyzed; the case of defocussed lamps is studied analytically. The temperature field in the sample is obtained by means of a conduction-radiation model that includes the radiative exchange between the sample and the mirror. Graphite-silicon-graphite samples are considered; the melting of the silicon part and the surface temperature distribution in the melt are analyzed in dependence of lamp defocussing. By changing this parameter opposite surface temperature gradients in the melt can be obtained, which define opposite thermocapillary stresses.