Study on classifying particle size and spatial internal flow field of T-shaped tooth structure in a disturbing rotary centrifugal air classifier

In the present study, three perturbed rotor structures were designed to investigate the performance of a new perturbed rotary centrifugal airflow classifier through experiments and numerical simulations. A model for the maximum and minimum classification particle size was established on the basis of the mechanical analysis of the blade. Pressure distribution and flow patterns at different positions in the Z-X and Z-Y planes of three structures under different rotational frequencies were analyzed, as well as the classification performance. The results show that in the rotor with different tooth structures operating at a critical rotational frequency, the internal flow field have abnormal pressure distribution, where the smaller density and velocity of the gas–solid phase reduce particle motion velocity, centrifugal force, and collision opportunities, forming particle sidewalls near the screen surface, thereby deteriorating the classification effect. The classification performance of the three structures under different operating parameters shows that when the rotation frequency exceeds 24 Hz, feed rate is 0.3 kg/s, and classifier inclination angle is −4°, the highest macroscopic and microscopic classification efficiency of the single-row tooth structure is 94.21% and 94.23%, respectively. The study can provide a reference to improve the flow field and classification performance of air classifiers in industrial applications.