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为了研究热容激光器冷却过程中激光介质的热力学特性,建立了激光介质热力学理论模型.该模型将介质表面的换热作为瞬态导热微分方程的热源,得到冷却过程中热传导模型.获得了激光介质在冷却过程中的瞬态温度场,进一步得到介质的热应力.利用数值模拟,得到了YAG介质和GGG介质在不同冷却条件下的冷却时间、温差和热应力.表面换热系数从0.1 W?cm-2?K-1增加到0.5 W?cm-2?K-1,冷却时间明显缩短;表面换热系数从0.5 W?cm-2?K-1增加到1 W?cm-2?K-1,冷却时间缩短不明显.对于相同体积、相同初始温度场的YAG介质和GGG介质,YAG介质的冷却时间少于GGG介质的冷却时间.在相同冷却条件下,YAG介质的温差小于GGG介质的温差,YAG介质的最大等效应力小于GGG介质的最大等效应力.
In order to study the thermodynamic properties of the laser medium during the cooling process of the heat capacity laser, a theoretical model of the laser medium thermodynamics is established. The heat transfer of the medium surface is taken as the heat source of the transient heat conduction differential equation and the heat conduction model is obtained during the cooling process. The thermal stress of the medium was further obtained in the transient temperature field during the cooling process.The cooling time, temperature difference and thermal stress of the YAG medium and the GGG medium under different cooling conditions were obtained by numerical simulation.The surface heat transfer coefficient increased from 0.1 W? cm-2 • K-1 to 0.5 W • cm-2 • K-1, the cooling time was significantly shortened and the surface heat transfer coefficient increased from 0.5 W • cm-2 • K-1 to 1 W • cm-2 • K -1, the cooling time shortened is not obvious.For YAG media and GGG media of the same volume, same initial temperature field, the cooling time of YAG media is less than the cooling time of GGG media.Under the same cooling conditions, the temperature difference of YAG media is less than that of GGG media The maximum equivalent stress of YAG medium is less than the maximum equivalent stress of GGG medium.