Hydrodynamics of a rotor–stator spinning disk reactor: Investigations by large-eddy simulation

Abstract

In this work, computational fluid dynamics are used to study the hydrodynamics in a complete rotor–stator spinning disk reactor with throughflow. Large-eddy simulations of OpenFOAM 9 were used to capture the turbulent structures of the flow in combination with the wall-adapting local eddy viscosity sub-grid-scale model. The method was validated based on residence time distributions (RTDs) for a range of rotational Reynolds numbers (Re = ωRD2ν−1 = 3.2–52 × 104) and a dimensionless flow rate (Cw = Q ν−1RD−1) of 150 and G = 0.0303 (G = h RD−1). The experimental RTD was obtained from tracer experiments with UV/VIS flow cells. From the RTD, the plug flow (PFR) volume fraction, the Péclet number, and the radial position (rtrans) where the flow changes from PFR into ideally mixed were determined by using an engineering model based on axial dispersion. For the turbulent cases, good agreement based on the RTD curve, PFR volume, the Péclet number, and rtrans was found. Furthermore, the boundary layer thickness on the rotor and stator and the entrainment coefficient were in good agreement with the literature. Finally, the turbulent intensity was analyzed illustrating a high intensity at the rim of the rotor and was 10% larger in centripetal flow compared to centrifugal flow.