氟化钙单晶炉温场的计算机模拟及改进

Computer Modeling and Improvement of Furnace Temperature Field for Growth of CaF_2 Single Crystal

对氟化钙晶体生长炉的顶部保温、加热器和下保温装置进行了改进研究。结合数值模拟,对改进前后晶体的轴向温度梯度、径向温度梯度和固液界面附近温度分布进行了对比分析。模拟结果表明,改进了顶部保温后增加了晶体炉内的辐射传热,有效降低了温度梯度,减小了晶体内热应力从而避免了晶体开裂;对加热器和底部保温进行改进后,减少了坩埚底部的热损失,相同温度时降低了加热功率。

The material of top heat insulation, heater diameter and bottom heat shield in the furnace for CaF2 crystal growth were investigated and improved. The axial temperature gradient, radial temperature gradient and temperature distribution around crystal/melt interface before and after improvement were analyzed by means of numerical modeling. The results show that higher heat-transfer by radiation could be obtained after improving the top heat insulation. As a result the temperature gradient reduce and crystal- crack avoid effectively due to lower thermal stress. After the reconstruction of heater and insulation, the heat loss of crucible was decreased and the heater power reduce at the same temperature.