Effects of Wall Roughness on the Separation Performance of Hydrocyclones under Different Inlet Conditions
Qiang Zhao, Baoyu Cui, Duanxu Hou, Dezhou Wei, Tao Song, Yuqing Feng
Abstract
Wall roughness is a crucial parameter in the manufacture and operation of hydrocyclones but has been underestimated. This study assesses the effects of wall roughness on the separation performance under different inlet conditions using a two-fluid model and an empirical wall roughness model that modify the logarithmic law of the wall. These models are proven to give good predictions for the in-house experiments on a ⌀150 mm hydrocyclone. The results indicate that small roughness is acceptable in use, whereas large roughness can significantly deteriorate the separation performance. The wall roughness mainly affects the pressure–kinetic energy conversion in the boundary layer by decreasing the tangential velocity and increasing the axial and radial velocities. All these changes further affect the air core diameter, the spatial distribution of particles, and finally, the separation results. The equal pressure condition can provide superior separation results with higher capacity than the equal flow rate condition but still cannot eliminate the adverse effects of wall roughness.