CFD Simulation of Air Flow Patterns in a Spray Dryer Fitted With a Rotary Disk

Abstract

The air flow pattern in a co-current pilot plant spray dryer fitted with a rotary disk atomizer was determined experimentally and modelled numerically using Computational Fluid Dynamics (CFD) (ANSYS Fluent ) software. The CFD simulation used a three dimensions system, Reynolds-Average Navier-Stokes equations (RANS), closed via the RNG k −ε turbulence model. Measurements were carried out at a rotation of the atomizer (3000 rpm) and when there is no rotation using a drying air at 25 ^oC and  air velocity at the inlet of  5 m/s without swirl. The air flow pattern was predicted experimentally using cotton tufts and digital anemometer. The CFD simulation predicted a downward central flowing air core surrounded by a slow recirculation zones near the walls for both conditions. Analysis of CFD simulation revealed that rotation of atomizer resulted in a swirling motion of the central air core. Simulations results were in good agreement with experimental data.