Numerical Investigation Of Free-Fall And Close-Coupled Gas Atomization For Metallic Powder Production

Authors: Yuanbin Deng (RWTH Aachen University, IWM, Germany) Jörg Fischer-Bühner (BLUEPOWER Casting Systems GmbH, Germany) Christoph Broeckmann (RWTH Aachen University, IWM, Germany) Abstract: Gas atomization is a widely applied industrial route for producing spherical metallic powders for powder metallurgical processing. Powder characteristics strongly influence processing and the final component performance. However, the highly transient and multiphase interactions between high-velocity gas flows and molten metal jets are difficult to access experimentally, thereby motivating the application of numerical simulations to investigate melt breakup and powder formation mechanisms. In this study, computational fluid dynamics models were developed to investigate both free-fall and close-coupled gas atomization. For free-fall atomization, melt jet instability, droplet formation, and particle size distribution were analyzed, confirming Rayleigh instability as the dominant breakup mechanism. A simplified axisymmetric nozzle model was also validated, which predicted particle size characteristics, particularly the mean particle size, that agree well with experimental data. For close-coupled atomization, the coupled breakup, cooling, and solidification processes were simulated, revealing a clear relationship between breakup trajectory and final particle size. DOI: https://doi.org/10.59499/EP267156454