Close-coupled nozzle atomization integral simulation and powder preparation using vacuum induction gas atomization technology

We simulate the gas-atomization process of a close-coupled annular nozzle for vacuum induction gas atomization at a three-dimensional scale.Moreover,the relationship between the simulated droplet type and experimentally metallic powder is established by comparing the morphology of droplets with powders.Herein,the primary atomization process is described by the volume-of-fluid(VOF)approach,whereas the prediction of powder diameter after secondary atomization is realized by the VOF-Lagrangian method.In addition,to completely reflect the breaking and deformation process of the metallic flow,we employ the VOF model to simulate the secondary atomization process of a single ellipsoidal droplet.The results show that the primary atomization process includes the formation of surface liquid film,appearance of serrated ligaments,and shredding of ligaments.Further,gas recirculation zone plays an important role in formation of the umbrella-shaped liquid film.The secondary atomization process is divided into droplet convergence and dispersion stages,and the predicted powder diameter is basically consistent with the experiment.In general,the four main powder shapes are formed by the interaction of five different typical droplets.     

顶吹深吹下熔池流场的研究(一)

一、前言 应用数学模型对顶吹下熔池流场进行研究,已经做了一些工作,这些工作都将凹陷以外的熔池自由面处理为水平面,且未考虑凹陷边缘有一对流场有重要影响的唇状突起的特征。在本文工作中,考虑了凹陷边缘有一唇状突起以及凹陷以外熔池的自由面并