Influence of Some Geometric Features of the Atomisation Chamber on Particle Agglomeration and Satellite Formation During Gas Atomisation

摘要

One of the main reasons to use gas atomisation is to obtain spherical powders with good flowability. The presence of satellites and agglomerates is undesirable because they widen the particle size distribution, increase the median particle size, and increase the irregularity of the powders. Moreover, they can become an important source of defects in final components. Particle agglomeration and satellite formation are associated with particle re-entry into the atomisation zone. Understanding these phenomena requires the simulation of the gas flow in the whole atomisation chamber. Despite its relevance, this kind of modelling has received very little attention compared to gas flow modelling around the nozzle region. Numerical three-dimensional simulations using Computational Fluid Dynamics (CFD) techniques were performed to model the gas flow and, therefore, identify the gas recirculation loops inside the atomisation chamber. The influence of the atomisation chamber’s dimensions and the locations of the outlet pipe are also analysed.