The Analysis Of Reduction Furnace Chassis Structure Based On The Homogenization Of The Temperature Field

The safety and energy-saving of the reduction furnace in the process of polysilicon production is vital, and it is a difficult problem that we must face in the process of polysilicon production. The temperature is upper than1100℃in the furnace, and the SiHCl3and H2react chemically. This process is not only energy-consuming seriously, but also will cause great safety difficulties for the device. Therefore, developing a way of efficient cooling mode and optimizing the device structure is of great significance to the development of the polysilicon production.The paper mainly discusses the development of the polycrystalline silicon reduction furnace chassis structure. In order to enhance the uniformity of the chassis internal temperature field and the security of the chassis structure, we improve the type of the chassis internal coolant’s flow channel. The chassis structure that this paper studies introduces a new type of the flow channel which is applied for coolant distribution and limiting jet to formate directly injection flow pattern. Compared with traditional chassis structure, the temperature distribution is more uniform inside the new type of chassis and it’s more difficult to form a gas membrane compartment under the surface of the chassis’s skateboard. This greatly reduces the thermal stress of the chassis skateboard and improve the security of the chassis structure. It describes the research of the thermal analysis involved radiation, heat conduction and convection using computational fluid dynamics (CFD) and draw the contours of the chassis internal temperature field, which is combined with the R&D of a large-scale polycrystalline silicon reduction furnace.Introduce the concept of uniformity coefficient, and analyze the factor on the impact of the reduction furnace chassis flow field. When the average arithmetic Celsius temperature of the chassis upper board is same or similar, the higher homogenizing coefficient, the smaller thermal stress and the higher chassis security; On the contrary, when the homogenization coefficient of the upper board is same or similar, the higher average arithmetic Celsius temperature, the lower security of the reduction furnace and the harsher the operation condition.When the inlet flow of the coolant is125-225t/h, calculate respectively the chassis three-dimensional flow field of the polysilicon reduction furnace, and get the chassis’ velocity field, temperature field and pressure field. Since the chassis limit jet injection diffusion channel is smaller, the total temperature of the internal flow field is lower, fluid turbulent kinetic energy is higher, the higher the fluid turbulent kinetic energy, the static temperature of the upper board is smaller, and the pressure drop is greater. So considering the flow rate and pressure drop, the selected inlet flow of170t/h is the optimal value.With the changes of the chassis limit jet injection flow channel’pore size, the arithmetic average Celsius temperature is liner change which’s shope is less than1; With the changes of the chassis limit jet injection flow channel’pore size, uniformity coefficient varies along the parabola. So considering the arithmetic average Celsius temperature and uniformity coefficient, the selected inlet flow of170t/h is the optimal value.