Visualization of the Precessing Vortex Core in a Cyclone Separator by PIV

The precessing vortex core (PVC) in a cyclone separator plays an important role in the separationperformance and in further understanding of the general law of periodic unsteady flow therein. In this paper, theunsteady flow field is investigated with particle image velocimetry (PIV), and the instantaneous velocity, vorticity,tangential velocity, and radial velocity are acquired by analyzing the images of instantaneous flow. It is for thefirst time reported that there is a centrifugal flow region close to the dust discharge zone and its maximum value ishigher than the mean radial velocity. This discovery is very important for understanding the principle of separationof particles in the area of dust discharge. Determination of the frequency and amplitude of PVC was conductedin the region where the phenomenon of PVC is remarkable. Results apree well with those obtained by hot wireanemometry. The observations of the center of vortex core and the bimodal distribution of the amplitude of thePVC indicate the v