Growth of large diameter silicon tubes can bring further advancements in the photovoltaic technology. Efforts are underway to grow first 50 cm and then 100 cm diameter tube using the current octagonal tube growth technique. A two-dimensional axisymmetric numerical model has been developed to simulate and design a large diameter cylindrical tube growth system. The model uses magnetic vector potential equation to predict the induced magnetic field and heat generation due to magnetic induction. A conduction-based model that accounts for the heat transfer by conduction, convection and radiation in various components of the system is employed to calculate the temperature held. The model predictions agree well with the experimental data. A parametric study is performed to examine the effects of number of coils, current, position of coil and geometry of the growth system, and to obtain the desired temperature profile. Numerical results for magnetic and thermal fields are presented for various cases. The goal of this investigation is to optimize the system with respect to the die tip temperature and temperature profile in the grown tube.