Bubble‐separation dynamics in a planar cyclone: Experiments and CFD simulations

Effect of Internal Vortex-Finder on Classification Performance for Double Vortex-Finder Hydrocyclone

The double vortex-finder hydrocyclone formed by a coaxial insertion of an internal vortex-finder with a smaller diameter inside the conventional single vortex-finder used to obtain two kinds of products from the internal and external overflows in one classification has attracted wide attention. To further improve the classification performance of the hydrocyclone, the effects of the internal vortex-finder diameter and length on the classification performance were studied by numerical simulation and response surface modeling with the behavior of fluid and particle motion in the double vortex-finder hydrocyclone as the research object. The results showed that the split ratio and pressure drop of internal and external overflow increased with the diameter of the internal vortex-finder. The classification performance was optimal when the diameter ratio of internal and external overflow was 0.88, the yield of −20 μm particles was more than 80.0%, and the highest was 95.0%. Increasing the internal vortex-finder length could reduce the coarse particle content and improve the classification accuracy of the internal overflow product. When the length of the internal vortex-finder is larger than 80 mm, the +30 μm yield was lower than 20.0%, and the maximum k value was 16.3%; the k is the significant factor used to characterize the effectiveness of −20 μm particle collection. The response surface modeling revealed that the internal vortex-finder diameter was the most important factor affecting the distribution rate of internal overflow. This paper is expected to advance the development of the classification industry.

Bubbly flow in degassing cyclones and potential applications

A degassing cyclone is a separator that is widely used for the removal of bubbles and dissolved gas from liquids. Gas bubbles move toward the swirling center region in a degassing cyclone due to centrifugal force. The dissolved gas is desorbed due to a decrease in the saturated solubility resulting from the pressure gradient in the degassing cyclone. Additional carrier gas bubbles with lower partial pressure lead to mass transfer at the turbulent bubble interface. The final state of the dissolved gas and carrier gas bubble in degassing cyclones is an important issue that can be used to develop a theoretical foundation for green separation engineering. The feasible development of this technology and potential applications are discussed in this work.