Abstract Summary (Max 250 words)
This work investigates numerical modelling strategies to describe the hydrodynamics in a standard 1.5 mL Crystal16 vial, a small-scale crystallizer agitated by a magnetic stirrer. A fully three-dimensional (3D), transient model is first developed using the shear stress transport (SST) turbulence model. Model simplifications are then explored, including a 3D transient laminar formulation and a two-dimensional axisymmetric (2D) steady-state approximation. The 3D turbulent flow solution is validated against literature data obtained from a steady-state single reference frame simulation with a k-ε RNG turbulence model [1]; good agreement is obtained. Although the flow at 1000 rpm has previously been described as moderately turbulent, a 3D transient laminar simulation shows a similar vertical velocity field, indicating that turbulence modelling may not be required at all. A 2D axisymmetric, steady-state, turbulent model is then constructed using a momentum source approach [2,3], where impeller effects are represented as volumetric forcing terms. Although minor discrepancies appear in the velocity profile, this simplification remains justified due the substantial reduction in computational cost, from 30h (3D turbulent) to 7h (3D laminar) and 25s (2D axisymmetric turbulent), all on a standard laptop. This low-cost approach is attractive for studying crystallization in stirred vials, enabling simulation of hydrodynamical particle interactions and the development of population-balance crystallization models. [1] Achermann et al., Chem. Eng. Sci., 256, (2022) [2] Joshi et al., Can. J. Chem. Eng., 89, (2011) [3] Huang & Li, Nuclear Reactor Thermal Hydraulics and Other Applications (Chap. 5), (2013)
