板状激光振荡介质温度场和应力场的数值模拟

NUMERICAL SIMULATION OF TEMPERATURE AND THERMAL STRESS FIELDS IN THE LASER SLAB OF A LASER OSCILLATOR

以非均匀内热源模型为基础,并考虑材料的导热系数和热膨胀系数的温度相关性,利用有限元方法,对板状激光振荡介质在不同功率和冷却强度下的温度和热应力分布进行了数值模拟及分析。根据计算结果提出了最大有效换热系数的概念,指出换热系数超过最大有效换热系数后,继续强化传热对减小高功率激光器的热效应已无明显效果。以此得出采用常规冷却技术所允许的最大泵浦加热功率。

The temperature and thermal stress fields in the laser slab of a laser oscillator were numerically analyzed using the finite-element (FE) method for different pumped powers under different cooling intensities. The analyses were performed based on a non-uniform heat source model with considering the temperature dependence of the thermal conductivity and expansion coefficient of the laser medium. Based on the calculation results, the concept of the maximum effective heat transfer coefficient was proposed. When the heat transfer coefficient exceeds this maximum value, further increasing of the heat transfer contributes little to the reduction of the thermal effects of a high power laser. The maximum permissible pumped heating power was eventually obtained for the conventional cooling case.