A quasi-stationary numerical model of atomized metal droplets. II: Prediction and assessment

A new model which extends previous studies and includes the interaction between enveloping gas and an array of droplets has been developed and presented in a previous paper. The model incorporates the probability density function of atomized metallic droplets into heat transfer equations. The main thrust of the model is that the gas temperature was not predetermined and calculated empirically but calculated numerically based on heat balance considerations. In this paper, the accuracy of the numerical model and the applicability of the model as a predictive tool have been investigated by comparing experimental and calculated results for the powder particles of 12Cr-Mo-V steel. The study also focuses on some aspects of the process which are not available experimentally, for example the effect of undercooling and the gas/metal ratio on the solidification. The important effects of these parameters are illustrated. A comparison between the numerical model and the experimental results shows an excellent agreement and demonstrates the validity of the present model, for example the calculated gas temperature which has an important influence on the droplet solidification behaviour as well as the calculated cooling rate of the droplets is found to be in good agreement with the experimentally determined value. The fact that the present approach of modelling is more general than previous studies opens up new possibilities for a deeper understanding of such a process without the limitation of experimental input parameters, for example gas temperature. Finally, the present approach of modelling and its predication illustrate the fact that quantitative results and guidelines can be drawn from this model which can then be used as a tool for the optimization of the process.

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