Stirred vessels are considered as the essential equipment in chemical and process industries. This research aims to simulate the impact of 33 distinct impeller designs on the mixing quality of solid–liquid stirred vessels in terms of solid cloud volume by the CFD technique. The RNG \(k-\varepsilon\) model was employed to simulate turbulence, along with the Eulerian–Eulerian approach for multiphase flow. The impeller motion was simulated using the MRF methodology. The influence of various impeller shapes on the solid–liquid mixing was explored across three distinct parts (Part I, II, and III). In Part I, three sets of impeller shapes including pitched blade (Part I—Set I), curved blade (Part I—Set II), and other shapes of impellers (Part I—Set III) were studied. Among the impellers in Part I, the pitched blade impeller with four \(45^\circ\) blades (PB-45d-4B) in Set I, the curved blade impeller with four \(45^\circ\) blades (CB-45d-4B) in Set II, and the A320 impeller in Set III reached the maximum solid cloud volume in their set. In Part II, by changing the blades numbers of Part I impellers, the pitched blade impeller with three \(45^\circ\) blades (PB-45d-3B) increased solid cloud volume up to 72% of vessel volume. In Part III, some geometrical modifications of the PB-45d-3B impeller in terms of twelve new impeller shapes showed adding a vertical blade to the main blades and a ring around the impeller increases the solid cloud volume up to 91.16% of vessel volume.
