激光能量和辅助气体对切割能力影响的数值模拟

Numerical simulation of effect of laser power and assistant gas on laser cutting ability

采用旋转高斯激光体热源和氧气流量控制的氧铁燃烧反应放热复合热源,基于计算流体力学建立了能够反映激光切割中激光能量、辅助气体和切缝之间相互作用的多相流模型.利用该模型对以氧气和氮气为辅助气体的激光切割过程进行了数值模拟,通过改变激光功率和辅助气体压力,研究了热输入和辅助气体流场对激光切割能力的影响,并对两种辅助气体的切割结果进行了比较和分析.结果表明,所采用的计算模型较好地模拟出激光功率和辅助气体对激光切割能力的影响,并对切缝形状进行预测.

Materials were cut with the coupled interaction of laser power and assistant gas during laser cutting process. A multiphase flow model was established, which was able to reflect the interaction among laser energy, assistant gas and workpiece during laser cutting based on computational fluid dynamics. A hybrid heat source model was used, including laser power and oxygen-flow controlled combustion reaction heat. Low carbon steels were cut by fiber laser with O2 or N2 as assistant gas, and the cutting process was numerically simulated. The effect of laser power and assistant gas on laser cutting ability was investigated by regulating the laser power and gas pressure. The calculated results show that the laser cutting ability was determined by the coupled interaction of laser power and assistant gas. The numerical simulation can calculate both the temperature and flow fields, and can also predict the shape of cutting seam.