为了提高激励源的热稳定性, 保证4kW轴快流CO2激光器的光束质量, 采用计算流体动力学的方法, 理论分析了激光器激励源热沉的散热机理, 对热流密度为106W/m2、面积为16cm2的激励源热沉结构进行了优化设计。结果表明, 经过优化之后的热沉其表面的最高温度低于340K, 完全能够满足激光器正常工作时激励源核心功率MOSFET对散热指标的要求; 同时经过数值模拟得到了带凹槽微通道热沉的优化结构尺寸, 分别是微通道凹槽间距P=0.6mm, 微通道凹槽倾角θ=45°, 微通道凹槽交错距离s=0.1mm, 同时当雷诺数Re=546.9时, 热沉有最优的散热效果, 激光输出功率的稳定度可以控制在±2%以内。此研究为设计具有高效散热能力的微通道热沉提供了理论指导。

In order to improve the thermal stability of excitation sources and ensure the beam quality of 4kW axis fast flow CO2 laser, the thermal dissipation mechanism of heat sinks of laser excitation sources theoretically was analyzed by means of computational fluid dynamics method. The heat sink structure of the excitation source with heat flux of 106W/m2 and area of 16cm2 was optimized. The results show that the maximum temperature on the surface of the heat sink is lower than 340K after optimization. It can fully meet the requirements of the heat source of MOSFET which is the core power of the excitation source in the normal operation of the laser. At the same time, by numerical simulation, the optimal structure size of the microchannel heat sink is obtained. The channel spacing P is 0.6mm, microchannel groove angle θ is 45°, and channel spacing s is 0.1mm. When the Reynolds number is Re=546.9, the heat sink has the best cooling effect. And the stability of laser output power can be controlled within ±2%. This study provides the theoretical guidance for the design of microchannel heat sinks with high heat dissipation capability.