| Cyclone separators were studied in three respects: investigation of flow field, development of separation models, and design of new cyclone type separators. Computational Fluid Dynamics was used to study flow fields in a conventional cyclone. Four popular turbulence models were selected to study the mean flow fields in the cyclone, and their predictions were compared with PIV experimental results. RSM has been proved to provide good predictions on the mean flow field. However, RSM provides poor predictions on the fluctuating flow field. The uniform design method was used to modify the standard coefficients in RSM, and the modified RSM gives much improved predictions on the fluctuating flow field.;Finally, two new dynamic cyclones with different rotary devices inside were designed, built, and tested. The experiments carried out with these two dynamic cyclones on the separation efficiency showed that they are efficient in removing fine particles. Numerical simulations were also conducted to investigate the dynamic cyclone flow fields for better understanding their separation mechanisms.;Based on the understanding of the flow field in conventional cyclones, a new multi-region separation model was developed analytically. The multi-region model used a more accurate position of the interface between the downward and the upward flows, and no requirement for geometry simplifications is needed. The multi-region model provided good predictions on the separation efficiency and responded well with various cyclone geometries and operating conditions for both industrial size and laboratory scale cyclones. |
