A vacuum environment results in a deep penetration depth in laser keyhole welding. In this study, the numerical simulations of laser keyhole welding in various vacuum conditions were performed with consideration for multiphysics phenomena. To consider the vacuum environment in numerical simulations, a modified recoil pressure model with the change in pressure and vaporization temperature according to ambient pressure and a laser power attenuation model by scattering and absorption due to the nanoparticles in the laser-induced plume was considered. For the scattering and absorption calculations, artificial coefficients obtained for a 1 atm condition were used, and then the coefficients in the other pressure conditions were calculated under assumptions suggested in this study. The simulation results using the models based on the assumptions could depict a deeper penetration in vacuum conditions considered in this study, and they were in good agreement with the experimental results in terms of weld cross section.

中文翻译：

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基于羽流模型的流体动力学模拟研究真空中激光小孔焊接

真空环境会导致激光锁孔焊接中的熔深较深。在这项研究中，在考虑多种物理现象的情况下，进行了在各种真空条件下激光锁孔焊接的数值模拟。为了在数值模拟中考虑真空环境，考虑了根据环境压力改变压力和汽化温度的改进后坐压力模型，以及由于激光诱导羽流中的纳米粒子引起的散射和吸收而产生的激光功率衰减模型。对于散射和吸收计算，使用在1个大气压条件下获得的人工系数，然后根据本研究建议的假设计算其他压力条件下的系数。