摘要:
出炉温度和冷却速率是大尺寸硫系玻璃制备过程中的关键参数.在热传导方程理论基础上,运用最小二乘拟合的方法建立计算圆柱形硫系玻璃冷却过程温度分布的理论模型.利用该模型对硫系玻璃的出炉温度、出炉后温度分布以及冷却速率进行了仿真分析,并将仿真分析结果与实验数据进行了比较.研究表明：出炉后玻璃棒的温度处于非稳态非均匀分布,其表面降温最快,且速率随时间呈现指数型下降;玻璃棒温度从中心到边缘近似呈抛物线型分布;当以高于析晶温度50—100℃,表面热交换系数180W·m-2K-1出炉时,玻璃最不容易析晶.在该理论模型指导下,实验上获得了直径为110mm,高为80mm的均匀透明圆柱形硫系玻璃.该玻璃透射谱范围是0.8—17μm,在8—12μm的区域内,2mm厚平片的平均透过率高于65%.
Abstract:
The tapping temperature and the cooling rate are the key parameters during the development process of chalcogenide glass.Based on the theory of heat conduction equation,a model for calculating the temperature distribution of cylindrical chalcogenide glass is established using the least square fitting method in this paper.The tapping temperature,the temperature distribution and the cooling rate are simulated by using the model.The simulation results are compared with experimental data.The results show that the glass temperature stays in a non-steady non-uniform distribution,the surface cooling is the fastest,and the temperature decreases exponentially with time when the glass is tapped off from the furnace;the temperature of glass rod from the center to the edge is approximately of parabola distribution;the crystallization is the most difficult when the glass is tapped off at 50—100℃ higher than crystallization temperature and a surface heat exchange coefficient of 180 W·m-2K-1.Under the guidance of the theoretical model the uniform and transparent chalcogenide glass with a diameter of 110 mm and height of 80 mm is obtained.The glass transmission spectrum range is 0.8—17μm.The 2 mm thick flat sheet has the average transmittance higher than 65% in a 8—12μm range.
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