Radiative heat transfer in a resistance heated floating zone furnace: A numerical study with FIDAP (TM)

This paper presents a numerical study of radiative heat transfer in a float ing zone (FZ) furnace which was performed by using the commercial finite el ement program FIDAP (TM). This resistance furnace should provide a temperat ure higher than the melting temperature of silicon (i.e. T-max approximate to 1500 degreesC) and a variable temperature gradient at the liquid/solid i nterface ( greater than or equal to 25 K/cm). Due to the high working tempe ratures, heat radiation plays the dominant role for the heat transfer in th e furnace. For this reason, the quality of view factors used in the wall-to -wall model was carefully inspected with energy-balance checks. A numerical model with two control parameters is applied to study the influence of mat erial and geometrical parameters on the temperature field. In addition, thi s model allows us to estimate the internal thermal conditions which were us ed as thermal boundary conditions for partial 3D simulations. The influence s of an optical lens system on the radial symmetry of the temperature field were. examined with these partial 3D simulations. Furthermore, we used the inverse modeling method to achieve maximum possible temperature gradients at the liquid/solid interface according to the limitation of maximum availa ble power and the maximum stable height of a melt zone.