激光切割过程辅助气体动力学性能的数值模拟

Numerical simulation on dynamic performance of assistant gas during laser cutting process

关键词:  激光切割  辅助气体流场  数值模拟  深度自适应热源

Key words:  laser cutting  assistant gas flow field  numerical simulation  depth adaptive heat source

摘要:

激光切割过程中辅助气体的动力学性能对切缝形成过程具有重要影响.利用VOF算法和深度自适应激光热源,建立了能反映切割过程中辅助气体和切缝之间相互作用的多相流模型,结合切割试验对模型的有效性进行了验证.采用多相流模型分析了从打孔到稳定切割过程中切缝形貌、辅助气体动力学性能和温度场分布.计算结果表明,在未切透阶段,受切割前沿形状和切割深度等的影响,辅助气体动力学性能不断发生变化;当切割过程稳定后,辅助气体流场几乎不发生变化,切缝形状和温度场也不再改变;所建模型能够有效反映辅助气体动力学性能对切割深度和切缝宽度的影响.

Abstract:

The dynamic performance of assistant gas plays an important role on cutting kerf forming in laser cutting process.The VOF method and depth adaptive laser heat source were used to set up a multiphase flow model which can simulate the interaction between assistant gas and cutting kerf.Cutting experiments were carried out to verify this model.The cut kerf morphology,dynamic performance of assistant gas and temperature distribution were investigated from holing to stable cutting in the total cutting process.The calculation results show that the dynamic performance of assistant gas changes constantly during laser holing,which is affected by cutting frontier shape and cutting depth,etc.Assistant gas flow,cutting kerf morphology and temperature are no longer changing during stable cutting stage.The model can effectively reflect the cutting depth and width which are influenced by dynamic performance of assistant gas.