The effects of the height-to-width ratio of the rectangular inlet on the flow field and separation performance by hydrocyclone

Abstract

ABSTRACT A rectangular inlet generally exceeds a circular inlet in separation performance. However, there still lacks detailed information that can appropriately determine the height-to-width ratio of the rectangular inlet. For this reason, this study investigated the effect of the height-to-width ratio of the rectangular inlet on the separation performance of hydrocyclone with a diameter of 75 mm through numerical analysis. The numerical results fitted well with the experimental data and thus validated the effectiveness of the present method. The appropriate height-to-width ratio was determined by overall analyzing the pressure field, the velocity field, the air column, the turbulence field in the hydrocyclone and the separation efficiency. Based on the present research results, as the height-to-width ratio increased, both the pressure drop and tangential velocity first increased and then decreased, while the turbulence energy first decreased and then increased. At a height-to-width ratio of 3, the short-circuit flow rate and the turbulence energy were lowest and the separation precision was highest, suggesting favorable product quality. Conclusively, for the hydrocyclone with a diameter of 75 mm, the optimal height-to-width ratio of the rectangular inlet should be within the range of 3~4. This finding can provide insightful foundation for designing a reasonable inlet.