Study on the law of turbulent flow and self-rotation and revolution of particles in micro-hydrocyclone

Global separation energy consumption accounts for 10-15% of the total one. The development of non-thermal separation instead of thermal separation opens up a novel direction for global energy development. As one of the classical non-thermal separation methods, the accuracy of cyclone separation is limited to the micron level due to the limitation of turbulent diffusion, and no revolutionary breakthrough has been reported on this approach in the past 100 years. The bottleneck is that the law of turbulent flow and particle motion in the hydrocyclone is unclear, and their pertinent research is difficult to be conducted. In the present paper, a slice test particle image velocimetry (S-PIV) methodology is proposed and employed to test the rotational turbulent flow characteristics of three different structures and flow rates. The results obtained by PIV (axial and radial veloc-ities) verify the accuracy of the present CFD simulation. On this basis, the consistency and correctness of the tangential velocity of the micro-hydrocyclone obtained by the CFD and S-PIV were compared. The results indicate that S-PIV can replace the expensive and cumbersome phase doppler particle analyzer (PDPA) and 3D velocity field (V3V). Based on the S-PIV and CFD, the characteristics of the turbulent flow, as well as the self -rotation and revolution of particles in micro-hydrocyclone were systematically explored. The law between the turbulent flow parameters and the self-rotation and revolution of particles was established. The influence of the inlet position of the hydrocyclone on the law between turbulent flow and particle motion was examined. The unsolved problem of the correlation theory between fluid flow and particle motion that has not been established since the invention of the hydrocyclone in 1891 was unlocked. The S-PIV methodology expands the PIV test technology from a two-dimensional flow field to a three-dimensional flow field, which is an innovation for examining the test method of the turbulent flow field.

Automated summary

Global separation energy consumption accounts for a significant portion of total energy consumption, and the development of non-thermal separation methods offers a new direction for global energy development. However, the accuracy of cyclone separation is limited, and no significant breakthroughs have been achieved in this field in the past century. This study proposes a slice test particle image velocimetry (S-PIV) methodology to explore the turbulent flow characteristics of different structures and flow rates in micro-hydrocyclones. The results demonstrate the effectiveness of S-PIV as a replacement for expensive and cumbersome particle analyzers, and establish the relationship between turbulent flow parameters and particle motion.