激光熔覆过程光束能量衰减的模拟

Simulation of Laser Attenuation in Coaxial Laser Cladding

为了应用能量守恒对同轴送粉激光熔覆中的熔覆层性能进行精确计算,研究了激光束穿过粉末云时能量的衰减现象和衰减规律.利用流体软件模拟实际喷嘴喷粉的过程,并利用有限元软件模拟激光束穿过粉末云的能量衰减规律,得到了激光-粉末相互作用区域内粉末云质量浓度随z轴的分布曲线,以及不同激光功率下和不同粉末云质量浓度下,从喷嘴出口到基材之间粉末云对激光衰减率的变化曲线.结果表明:激光束穿过粉末云的过程中,未到粉末交汇处时光强衰减较弱,汇聚处能量衰减明显.对衰减率进行定量研究可以很好地用于熔池温度场的精确计算.

In order to calculate the properties of cladding layer in coaxial laser cladding using energy conservation accurately,the energy attenuation phenomena and rules of laser were researched when laser beam got across through the powder cloud. The powder feed process of a nozzle model was built according to the real nozzle by fluid software and the process that laser beam got across the powder cloud model by finite element software was simulated. The variation trend of powder cloud mass concentration was obtained along with z axis in laser-powder interaction area, and the changing curve of laser attenuation ratio from nozzle exit to substrate in different laser power and powder cloud mass concentration was derived. It shows that attenuation before powder focused is weaker compared to the powder focused region. Quantitative research of laser attenuation ratio is beneficial to the accurate calculation of molten pool temperature field.