Partic. vol. 29 pp. 34-47 (December 2016)
doi: 10.1016/j.partic.2015.09.010

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

Alexander Stroh^*, Falah Alobaid, Max Thomas Hasenzahl, Jochen Hilz, Jochen Ströhle, Bernd Epple

alexander.stroh@est.tu-darmstadt.de

Abstract

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.

Graphical abstract

Keywords

Computational fluid dynamics; Euler–Lagrange-deterministic collision model; Euler–Euler; MP-PIC approach; Experimental validation