Study Of Flow Field Characteristics And Dispersion In A Turbo Air Classifier

The turbo air classifier is a very important powder classification device. Dispersion is a premium condition that actualizes ideal classification because the material must be dispersed completely before they enter the classifier. Good separation effect depends on the reasonal flow, which is a necessary condition for the classification. In this study, the flow field characteristics and material dispersion in the turbo air classifier were investigated and analyzed.The airflow pre-dispersion equipment was installed in a turbo air classifier before the raw materials were classified. Raw materials were suspended to disperse and conveyed to classifier by pressured airflow. The classification tests of talc and limestone powder were made and the effect of airflow pre-dispersion on classification performance was investigated under different conditions. The results show that output percentage and Newton classification efficiency of fine powder are increased with the increase of dispersion air velocity, and cut size becomes bigger. The superfine particles (<4μm) in the limestone powder of the small mean diameter are not prone to be pre-dispersed.Velocity measurement of the annular region in a turbo air classifier is performed by Laser Doppler Velocimeter (LDV). At first the effect of the pre-dispersion airflow on the flow field characteristics was studied. It is...