An integrated multi-size collision model for flotation

TL;DR

This paper introduces the Integrated Multi-Size Collision model (IMSC) for flotation, improving collision rate predictions by addressing size differences and turbulent flow coupling, validated with DNS and literature data.

Contribution

The paper presents a novel collision model that integrates existing approaches and new developments, enhancing accuracy in flotation simulations.

Findings

IMSC outperforms existing models in predicting collision rates.

The model accurately covers the entire flotation parameter range.

Validation confirms the model's assumptions and robustness.

Abstract

The accuracy obtained with CFD and process simulations of flotation critically depends on the quality and robustness of the underlying models for the non-resolved sub-processes. An important issue in flotation is the collision between particles and air bubbles. Many models have been developed, but their accuracy for applications in flotation is limited. In particular, the significant size difference between particles and bubbles and their intricate coupling to the turbulent flow field pose severe challenges. The present paper first reviews presently employed collision models, highlighting their advantages and disadvantages when applied to flotation. On this basis, the "Integrated Multi-Size Collision model" (IMSC) is proposed. After a detailed evaluation, it combines existing approaches from various sources and introduces new developments designed to address present shortcomings. The model is validated by own DNS data as well as data from the literature. It is shown that, overall, the IMSC provides better predictions for the collision rate in typical flotation conditions than presently employed collision models and covers the entire parameter range of the flotation process very well. Using the available data, some of the underlying modelling assumptions are validated. Finally, a comprehensive overview of the model is provided for further use in Euler-Euler frameworks or process simulations.