Research And Numerical Simulation Of Thermal Field For The Polycrystalline Silicon Ingot Production Furnace

The polycrystalline silicon ingot production furnace is used for casting large-scale polysilicon ingot,which is expected to be condensation crystallization through directional solidification after high temperature silicon melt,it agrees to form crystalline silicon ingots,so as to achieve the production of silicon solar cells quality.Thermal field refers to the temperature distribution of the heating system for the polycrystalline silicon ingot production furnace.It is vital to the growth of polycrystalline silicon crystals.The Crystal cooling process,the shape of solid-liquid interface,the thermal stress distribution of crystal and so forth are all deterrninated by the thermal field and temperature gradient during crystal growth process.Therefore, the thesis put the emphasis on the thermal field's study of the polycrystalline silicon ingot production furnace.The main achievements in the thesis are as follows:1,The heat transfer and the decompression process were studied during the directional solidification of the polycrystalline silicon ingot production furnace. Optimization design was put forward for the thermal field's heater.The heater's material,the structure shape and the geometry size were all determined.At the same time,the water-cooled electrode's structure style was optimized.2,The technnical solution of the heat shield was proposed.The heat shield's material and configuration was analyzed.Making use of the finite difference method, temperature distribution of the heat shield was calculated.3,Configuration form and geometry dimension of the vacuum heating chamber was researched.As the polycrystalline silicon ingot production furnace's heart part, the vacuum heating chamber's reasonable design guaranteed the thermal field on the safe side.4,In this paper,the temperature distribution of the crystal and melt in growth process was discussed.And the temperature field of the solid-liquid interface was studied.The crystal growth process was visualized by the numerical simulation.A systematic theoretical analysis and experimental validation was provided after the optimization design of the thermal field for polycrystalline silicon crystal growth.