Model of quench cooling and experimental analysis of cylindrical infrared chalcogenide glass

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 50100 ℃ 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 0.817 m. The 2 mm thick flat sheet has the average transmittance higher than 65% in a 812 m range.