Design of partial cross-sectional geometry and prediction of separation performance in the spiral separator

Understanding the influence mechanism of the partial cross-sectional geometry of a spiral separator on the flow field characteristics and particle separation performance is conducive to the design of a combined cross-section profile. The impact of the trough slope in the inner and middle troughs on the flow field characteristics and particle separation performance was investigated by CFD methods. The results show that the average depth of the flow film, the average tangential velocity, and the average radial velocity in the partial radial region are linearly related to the trough slope. With the increase in the trough slope in the inner and middle troughs (r = 30-110 mm), the radial velocity reversal position will decline, resulting in an enlarged proportion of the outward flow. Adjusting the trough slopes of the two straight segments in the inner and middle troughs will have a positive effect on the precise segregation of particles. In comparison, changing the trough slope in the middle trough containing the miscible band had a more significant effect on particle separation. A maximum separation efficiency of 80.80% was obtained with a trough slope in the middle trough of 5 degrees and a splitter position of 95 mm.