A numerical modeling framework for predicting the effects of operational parameters on particle size distribution in the gas atomization process for Nickel-Silicon alloys

Gas atomization is utilized to produce good-quality metal powders. A numerical modeling framework is developed to simulate the gas atomization process. A two-phase VOF flow model in OpenFOAM is applied to track the primary breakup of the melt stream by a high-speed gas flow. The generation of primary melt droplets is extracted from the VOF field. A Lagrangian-Eulerian multiphase flow model in Ansys Fluent is adopted to track the secondary breakup of the primary melt droplets under the high-speed gas flow. The final particle size distribution is obtained by analyzing the particles sampled at the outlet of the atomization chamber. The process of gas atomization can be affected by many factors such as the atomization equipment, operating parameters, and material properties. Sensitivity analysis is conducted through modeling to investigate the effects of these factors on particle size distribution. The model predictions are validated by specially designed gas-atomization experiments. A CFD-based numerical modeling framework is developed to simulate the gas atomization process, including both the primary breakup of the melt stream by a high-pressured inert gas flow jet and the secondary breakup of the melt droplets generated after the primary breakup stage inside the atomization chamber using different models. They are integrated within the modeling framework to consider the comprehensive flow physics in the gas atomization process. A gas atomization test for Nickel-Silicon alloys is designed and performed. The particle size distribution of the powders produced in the gas atomization test is used to validate the model predictions. Good agreement between the model predictions and experimental observations shows the success of the modeling framework. In addition, a systematic sensitivity analysis is performed through simulations to investigate the effects of various operating parameters on the particle size distribution of the powders produced by gas atomization.