The influence of dipleg shape on the flow pattern and performance of gas-solid cyclone was investigated. Different diplegs including cylindrical, inverted cone, conical, and diamond were studied. Due to the turbulent nature of the flow in the cyclone, the RSM turbulence model was used in the simulations. It was found that the mean tangential velocity in the cyclone for different dipleg geometries were about 1–1.2 times the inlet velocity, while the maximum tangential velocity was 1.7 times the inlet velocity. In addition, the tangential velocity in the cylindrical dipleg was greater than those of the other dipleg models. Changes in the dipleg shape significantly affect the axial velocity in the dustbin. The maximum axial velocity was observed in the vortex finder region and the entrance region of the dipleg for different models. It was also found that the dipleg geometry significantly affected the cyclone pressure drop. The cylindrical dipleg generated the highest pressure drop, whereas the lowest pressure drop was seen for the cyclone without dipleg. Among the studied geometries, the highest efficiency was found for the cyclone with conical dipleg and the diamond dipleg led to the lowest efficiency. Finally, the influence of constant parameter of the eddy lifetime model on the turbulent dispersion of particles and the corresponding cyclone performance was studied.
