Development of an integrated multichannel inlet for improved particle classification in hydrocyclones

The inlet design of hydrocyclones determines the flow field symmetry and facilitates the formation of vortices. In this study, an integrated multichannel inlet based on the Archimedes spiral is developed to improve particle classification by combining the advantages of existing designs. Hydrocyclones with conventional tangent or novel spiral inlets are comparably studied to evaluate the feasibility and superiority of this design using the validated volume of fraction model and two-fluid model. Numerical results show that this novel spiral inlet dramatically improves the flow field symmetry in terms of radial velocity and air core as well as reduces the short-circuit flow and circulation flow. In addition, it also provides strong diversion and pre-separation effects on particles. Consequently, this novel spiral inlet provides superior classification performance than the conventional design, appearing in smaller cut-size, higher cut sharpness, and higher capacity. Such advantages become less evident with increasing channel number, due to the increased turbulence intensity caused by the additional feed streams. The spiral inlet with two channels can largely resemble the design with two tangential inlets in all indices, which makes it the most suitable in this study. This design method can be easily extended to other types of hydrocyclones.