Simulation of aerodynamics of a swirling turbulent flow in a centrifugal air classifier

Centrifugal air classifiers are the promising devices for fractional separation of powders by size. Large particles of a powder material are thrown to the periphery due to the predominance of centrifugal forces over aerodynamic forces. This paper studies the aerodynamics of a swirling turbulent flow for different working area designs of the classifier. Turbulence is simulated using the RANS method and the Wilcox turbulence model. To determine the efficiency of the classification of the powder material and to obtain a separation curve using the Tromp method, two calculation methods, i.e., trajectory and probabilistic methods, are proposed. The obtained results are validated with experimental data and through various test studies. Analysis of the numerical study of fine powder classification has shown the viability of the proposed geometry for a separation chamber in comparison with the traditional geometry. The most optimal mode of aerodynamic characteristics of the centrifugal classifier is revealed to obtain the best sharpness of particle size separation.