A numerical model for gas flow and droplet motion in wave-plate mist eliminators with drainage channels

Computational fluid dynamics (CFD) is used to develop Eulerian/Lagrangian models of two wave-plate mist eliminators, both equipped with drainage channels. The models are assessed through comparison with comprehensive experimental data on removal efficiencies and pressure drops. For the range of droplets sizes of interest for demisting operation, the turbulent dispersion model is found to play a fundamental role in determining the droplet motion. However, classical dispersion models, as the eddy interaction model, often available in commercial CFD codes are unsuited, resulting in errors on the removal efficiency larger than 100% for the investigated cases. Therefore, a simple procedure for the modification of the code in order to replace the dispersion model with alternative models by using the existing Lagrangian algorithm is proposed. Predictions with a varied eddy interaction model are observed to match closely experimental data on removal efficiencies. An analysis of the turbulence models is also carried out, those for low Re resulting in a better description of the gas flow field and droplet motion. (C) 2008 Elsevier Ltd. All rights reserved.