激光立体成形粉末流输送的数值模拟研究

Numerical Simulation of Powder Feed of Laser Solid Forming

激光立体成形（LSF）技术是一项基于同步送粉激光熔覆技术的先进增材制造技术。粉末流的输送对于沉积层的形成至关重要。通过建立载粉气流的湍流模型并基于粉末颗粒在气体湍流中的运动分析,采用数值模拟方法建立粉末流输送的数学模型,并利用Fluent软件进行求解,从而获得粉末流的质量浓度分布。将实验测量结果与模拟计算结果进行对比分析。结果表明,计算结果与实验测量结果比较吻合。对比粉末粒径范围为50~240μm的粉末流和粉末粒径范围为65~75μm的粉末流的模拟结果发现,在相同送粉工艺条件下,粒径分布范围不同则粉末流颗粒质量浓度有明显差异。

Laser solid forming（LSF） is a promising manufacturing technology.During LSF process,powder flow plays an important role in the formation of deposition layer.A turbulent flow model is build,and based on the analysis of the movement of particles in the turbulent flow,a powder flow model is developed by the numerical method and solved by using the Fluent software,so the powder mass concentration of the powder flow can be obtained.Comparisons between the simulations and the experimental results are carried out.It is found that the simulations of the powder flow agree well with the experimental measurements.The powder mass concentrations have a few obvious differences with the change of particle diameter range,as proved by the simulation results of particle diameters of 50~240 μm and 65~75 μm.