侧面抽运板状激光介质的热汇冷却

Cooling of a Side-Pumped Laser Slab by Heat Sink

高热负荷固体激光介质的热效应已经成为制约激光器功率进一步提高的严重障碍,只有对激光介质进行有效的冷却才能保证其安全运行。以不均匀换热系数模型为基础,研究了具有非均匀内热源的侧面双向抽运板状激光介质在狭窄通道强制对流冷却情况下的耦合换热问题,对热汇冷却方案下介质的温度分布和热应力分布进行了数值模拟和分析,并对复合介质、蓝宝石和金刚石三种热汇材料进行对比。结果表明,忽视换热系数的非均匀性将导致应力计算结果偏低。对于侧面抽运、侧面冷却的激光介质,金刚石热汇冷却方案最佳,蓝宝石热汇方案次之,而复合介质方案不宜采用。

The thermal stress of the high-power solid-state laser slab is becoming a more and more serious problem hindering the further increase of the power of the laser, the laser slab can operate safely only if it is efficiently cooled. Based on the non-uniform heat transfer coefficient model, researches are performed on the cooling characteristics of the both side-pumped laser slab with non-uniform heat source by forced convection cooling in a narrow passage. Numerical simulations are conducted to investigate the temperature and thermal stress distributions of the laser slab cooled by forced convection cooling through heat sink. Three kinds of materials are selected to serve as the heat sink, they are the composite slab, sapphire, and diamond, respectively. The calculation results show that neglecting the non-uniformity of the convective heat transfer coefficient causes an underprediction of the temperature and thermal stress of the slab. For the present side-pumped/side-cooled laser slab case, the cooling scheme using the diamond heat sink is the best, that using the sapphire heat sink follows, whereas that using the composite slab heat sink does not apply.