Gas atomization is now an important production technique for Fe-based amorphous alloy powders used in additive manufacturing, particularly selective laser melting, fabricating large-sized Fe-based bulk metallic glasses. Using the realizable k-ε model and discrete phase model theory, the flow dynamics of the gas phase and gas-melt two-phase flow fields in the close-wake condition were investigated to establish the correlation between high gas pressure and powder particle characteristics. The locations of the recirculation zones and the shapes of Mach disks were analyzed in detail for the type of discrete-jet closed-coupled gas atomization nozzle. In the gas-phase flow field, the vortexes, closed to the Mach disk, are found to be a new deceleration method. In the two-phase flow field, the shape of Mach disk changes from “S”-shape to “Z”-shape under the impact of the droplet flow. As predicted by the wave model, with the elevation of gas pressure, the size of the particle is found to gradually decrease and its distribution becomes more concentrated. Simulation results were compliant with the Fe-based amorphous alloy powder preparation tests. This study deepens the understanding of the gas pressure impacting particle features via gas atomization, and contributes to technological applications.

气体雾化现在是用于增材制造的铁基非晶合金粉末的重要生产技术，特别是选择性激光熔化，制造大尺寸铁基块状金属玻璃。利用可实现的k-ε模型和离散相模型理论，研究了近尾流条件下气相和气熔两相流场的流动动力学，建立了高压气体与粉体颗粒特性之间的相关性。详细分析了离散射流封闭耦合气体雾化喷嘴的回流区位置和马赫盘形状。在气相流场中，靠近马赫圆盘的涡流被发现是一种新的减速方法。在两相流场中，马赫圆盘的形状从“ S在液滴流动的影响下，“-”形变为“ Z ”形。正如波动模型所预测的那样，随着气压的升高，发现粒子的尺寸逐渐减小，分布变得更加集中。模拟结果符合铁基非晶合金粉末制备试验。该研究加深了对气体压力通过气体雾化影响颗粒特征的理解，并有助于技术应用。