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烧蚀热可用于材料抗激光加固性能表征和材料的激光加工效率描述。实验研究了亚音速表面切向空气气流速度和激光功率密度对玻璃纤维/树脂复合材料烧蚀热的影响规律,结果表明,相同气流速度下,烧蚀热在100~500 W/cm2激光功率密度范围内先迅速降低然后趋于稳定,转折点约位于200 W/cm2;相同激光作用下,功率密度较低时,烧蚀热随着气流速度提升而变大,功率密度高于一定值(约200 W/cm2)后,烧蚀热随气流速度提升而降低。分析认为材料内部扩散、热解气体燃烧、残碳氧化放热、辐射能量损失、气流剥蚀等多个因素的竞争是激光能量利用效率变化的原因。
Ablation heat can be used to characterize the material’s resistance to laser hardening and to describe the laser processing efficiency of the material. The influence of subsonic airflow velocity and laser power density on the heat of ablation of glass fiber / resin composites was investigated experimentally. The results show that the ablation heat at 100 ~ 500 W / cm2 laser power density Within the range, the temperature rapidly decreases and then stabilizes. The turning point is about 200 W / cm2. When the power density is low under the same laser power, the heat of ablation increases as the air velocity increases, and the power density is higher than a certain value (about 200 W / cm2), the heat of ablation decreases as the gas velocity increases. The analysis shows that the competition of many factors such as internal diffusion of material, combustion of pyrolysis gas, oxidation and exothermic of residual carbon, loss of radiative energy and ablation of airflow is the reason of the change of laser energy utilization efficiency.