高功率激光片状放大器片腔内流场模拟及优化

Simulation and Optimization of Internal Flow Field in High Power Laser Slab Amplifiers

片状放大器腔内钕玻璃表面的洁净度是保证放大器高工作性能和长寿命的关键指标,而合理的腔内流场分布是放大器保持腔内洁净的前提条件。运用计算流体力学方法,利用Fluent软件对纯氮气冲洗片状放大器过程中的腔内流场进行模拟,并在样机上验证了模型的有效性;通过调整放大器的进出气口结构及位置排布,获得了最佳的流场分布。实验结果表明,相比未优化放大器,优化后的放大器仅使用一半时间就可以达到相同的腔内洁净度等级,且钕玻璃表面洁净度更高。

The cleanliness of neodymium glass surface in the slab amplifier is a key indicator of guaranteeing highperformance and long lifetime of amplifiers, and the reasonable internal flow field distribution is the prerequisite forkeeping clean in the amplifier cavity. By means of computational fluid dynamics method and with the Fluentsoftware, the internal flow field of slab amplifier cavity in the purging process of pure nitrogen is simulated, and themodel validity is verified on the prototype system. By adjusting the structure and location arrangement of air inletsand outlets of the amplifier, the optimal flow field distribution is obtained. The experimental results show thatcompared with those of the non-optimized amplifier, the optimized amplifier not only takes only half time to obtainthe same required cleanliness, but also the cleanliness of neodymium glass surface is higher.