新型多晶硅还原炉底盘流动与传热的数值模拟

多晶硅还原炉的底盘取热结构对降低能耗有很大影响,提出了一种新型的多晶硅还原炉底盘均匀取热结构,并就其温度均匀性、冷却效果与传统底盘结构进行比较。该新型底盘结构由中间隔板分为2层,并在隔板上安装电极位置的孔周围焊接竖直环隙。冷却水由隔板下层的冷却水进口进入底盘并流经各电极周围的环隙进入隔板上层的还原炉底盘上底板实现均匀取热。与传统多晶硅还原炉底盘结构相比,该结构克服了传统结构下底盘取热不均匀的问题。就新型底盘取热结构中的单棒环隙结构进行模拟优化。重点考察环隙上焊接挡板的厚度、宽度及数量对冷却效果的影响。300 K的冷却水做工作介质,底盘材料用不锈钢。模拟后得到的单棒环隙结构的最适宜结果为竖直环隙挡板厚度1 mm,挡板宽度1 mm,挡板间距10 mm;水平环面挡板厚度1 mm,挡板宽度1 mm,挡板间距10 mm;换热效果较传统底盘提高32%,温度均匀性提高54%。

Numerical Simulation of Flow and Heat Transfer in a Novel Polysilicon Reduction Furnace's Baseboard

Siemens process energy consumption can be limited by furnace's baseboard temperature. An analysis based on mass and heat transfer theory, on different types of baseboards and a new type of baseboard structure are studied in detail in this paper. This new type is contained of two chambers cut by a barrier where several sleeves are welded around the electrodes. When the furnace works, the cold water, which passes through the sleeves from the lower chamber to the upper chamber, takes the heat from the hot electrodes and the furnace's baseboard. The baseboard temperature of higher degree of uniformity is realized in this type of baseboard,compared with the traditional ones. The effect of flow geometry parameters on heat transfer for turbulent flow in the sleeves with baffles inserts has also been investigated. Different flow geometry parameters of baffle width (W), baffle thickness (T), pitch (P) were varied parametrically during the experiments. Water, temperature of which is 300 K, was used as working fluid, while stainless steel was considered as sleeve and baffle material. The best effect of cooling performance is the type with the parameters of W_b=1 mm, T_b=1 mm, P_b=10 mm;W_t=1 mm, T_t=1 mm, P_t=10 mm and prompts 32% increase in heat transfer effect and 54% in uniformity of temperature.