NUMERICAL ANALYSIS ON MULTIPHASE FLOW IN NEAR-WALL AND NEAR-BOTTOM AREAS

To mix a solid-liquid multiphase flow more uniformly before filling, this paper numerically analyses the multiphase flow field distribution in the near-wall and near-bottom areas in the agitator tank under the effect of spiral ribbon-frame combined paddle, with the aid of the Eulerian multiphase flow model. The results show that, compared to the spiral ribbon paddle, the combined paddle structure with an additional frame paddle could weaken the high-density aggregation in near-wall and near-bottom areas, and reduce the low-density area on the top, making the flow more uniform. As far as the near-wall area is concerned (200-220 mm from the centre), compared to the combined paddle with oblique outer frame, the combined paddle with straight outer frame improves the uniformity of density distribution for the mixed multiphase flow, stabilizes the volume fraction of each single phase, and reduces the deviation from the set value (4 % - 17 %). The numerical analysis may guide the flow mechanism research of the mixing process of complex solid-liquid multiphase flow, and promote the optimal design of mixing structures.