Study on internal flow field of rotary triboelectric separator based on CFD simulation: fly ash as reference sample

Abstract

ABSTRACT CFD simulation is carried out for the internal flow field of rotary triboelectric separator by Fluent software, analyzing effects of three factors on airflow field inside rotary triboelectric separator, including feeding airflow speed, friction wheel speed, and assistant airflow speed. The best referenced simulation conditions are obtained by single separation test: the plate voltage of 24 kV, the feed frequency of 22 Hz, the friction wheel speed of 189.95 rad/s. Simulation results of feeding airflow speed show the feeding airflow speed of 4 m/s is a cutoff point of the influence for the maximum airflow velocity in the friction chamber, the sorting effect becomes worse when the feed air speed is greater than 4 m/s. Increases of feeding airflow velocity cause two effects: One is that feeding airflow can reach the surface of the friction wheel and then rotate with the friction wheel. The second is to increase the turbulence of the airflow field in the friction chamber; Simulation results of feeding airflow speed show when the rotational speed of the friction wheel is greater than 189.95 rad/s, the influence of the rotation friction wheel exceeds the airflow of feeding airflow. Under the condition of a certain feeding airflow speed, an increase of friction wheel rotate speed makes internal friction flow field velocity increase with the improve of velocity gradient, which leads to the flow field in the friction chamber is more uniform; Simulation results of assistant airflow speed show the 3 m/s assistant airflow in the sorting chamber is most beneficial to the stability of the material motion. The assistant airflow speed mainly affects the airflow field in the separation chamber, the flow field in the separation chamber is increased with the increase of the assistant airflow speed.