The Euler-Euler/RANS approach is used to simulate the particle suspension in solid–liquid stirred vessels, with experimental validation conducted through the Electrical Sensing Zone Method (ESZ). An innovative evaluation method is introduced to quantify the critical impeller speed Nc required for particles to achieve a specific uniform suspension state in dilute solutions. The impact of different vessel bottom shapes (flat, round, and W-shaped) on particle suspension characteristics is examined. The results indicate that optimizing the bottom shape to align with flow streamlines markedly enhances particle suspension, a conclusion supported by the Online Micro-sized Particle Analyzer (OMiPA). Further analysis shows baffle configurations transform tangential and axial velocities into radial velocity, which is not conducive to providing initial conditions for particle suspension. Overall, effective particle suspension relies on the interaction between main flow and turbulent fluctuations, with tangential and radial flows playing critical roles.