Enhancement of hydrocyclone separation performance by eliminating the air core

A new hydrocyclone was designed with a solid core fixed along the central axis in this study. By introducing the solid core, the air core inside the hydrocyclone could be eliminated effectively. Comprehensive effects of eliminating the air core by the solid core on the hydrocyclone performance indices were experimentally investigated. To examine the influence mechanism of air core on the separation performance, a Laser Doppler Anemometer (LDA) was used to investigate the turbulent flow field inside hydrocyclones with and without air cores. The results showed that the radial and axial velocity components in the area near the entrance of the vortex finder, and the radial and axial turbulence components were all reduced by eliminating the air core, i.e. the flow field characteristics inside the hydrocyclone with solid core became more suitable for the separation process. By replacing the air core with solid core, the hydrocyclone separation performance was improved effectively. Comparing the hydrocyclones with air core and solid core, it was proved to be featured with higher total separation efficiency, larger reduced separation efficiency, smaller corrected cut size and higher separation sharpness, although the hydrocyclone cone shape changed from common type, to parabola type, and to hyperbola type. By increasing the inner space of the hydrocyclone cone, the improvement of separation performance became more remarkable.