Abstract：Aiming at the helical flow produced by hydrocyclones with different guide vane heights, the effect of helical flow was studied by taking the velocity and momentum of the outlet section as parameters. In this paper, by means of numerical simulation and physical tests, the hydraulic cha-racteristics of a hydrocyclone with different guide vane heights were studied from the aspects of the velo-city cloud of the outlet section, the velocity distribution interval of the section, the momentum of the fluid passing through the section and the average pressure of the section. The results show that with the increase of guide vane height, the axial velocity relative low speed zone expands and the velocity extreme value increases. Also, the influence area of radial velocity expands, and the radial velocity ranges from -0.27 m/s to 0.33 m/s. The area of the annular region affected by the tangential velocity increases along the radial direction, while the maximum value decreases, but the mean value increases from 0.13 m/s to 0.30 m/s, and the velocity distribution is more uniform with a stronger intensity. The ratio of tangential momentum to axial momentum of fluid passing through the outlet section is η, which increases from 0.07 to 0.14, and the flow rate Q has little effect on η. This study provides a reference for the selection of the structure parameters of the hydrocyclone.
