Comparison of three different CFD methods for dense fluidized beds and validation by a cold flow experiment

This work focuses on a comparison between three different numerical CFD methods, namely Euler-Euler, Euler-Lagrange-stochastic, and Euler-Lagrange-deterministic, to treat a dense spouted bed. A simple cold flow experiment was used to investigate the hydrodynamics of a gas-solid flow in a three dimensional lab-scale spouted bed. In this context, two different air mass flow rates, 0.005 and 0.006 kg/s, were applied during fluidization. The experimental bed behaviour was recorded with a high-speed camera to validate the numerical predictions in terms of bubble size, bed expansion rate, and particle velocities at different reactor heights. The numerical setup was kept similar between all three modelling approaches. At both gas mass flow rates all three approaches are able to capture the overall bed expansion. However, at higher gas mass flow rates, discrepancies between experiment and simulation increase for the Euler-Euler and Euler-Lagrange-stochastic models. The Euler-Lagrange deterministic model most accurately predicts the flow pattern at both mass flow rates. The main reasons for discrepancies between simulation and experiment result from modelling of the collision and friction forces. (C) 2015 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.