Investigation of Fluid Flow Behavior in a Gas Atomization Process for Metal Powder Production

Additive manufacturing techniques such as 3D printing, electron beam melting (EBM), selective laser melting, and metal injection molding (MIM) have become increasingly popular due to their unique benefits. However, these emerging processes still require well-characterized materials. The gas atomization technique offers a promising solution for producing metal powders suitable for these processes. In this study, aluminum melt was gas-atomized using nitrogen gas through a lab-scale gas atomizer with a melt delivery nozzle diameter ranging from 7 mm to 2 mm. The resulting powder particles ranged in size from 50 µm to 300 µm. However, premature stoppage of atomization occurred due to clogging of the melt in the nozzle, likely caused by uneven pressure distribution inside the atomizing chamber. Computational fluid dynamics (CFD) simulations were used to investigate the flow behavior and pressure distribution inside the chamber. The simulations revealed that the pressurization condition near the nose of the melt delivery nozzle was one of the primary reasons for the melt tube clogging. Modifications to the design were proposed to overcome this issue, such as establishing recirculation and pressurization controls.