(140e) Numerical Simulation of Dense Gas-Solid Fluidized Beds: Comparison Between Eulerian Multiphase and Discrete Element Methods

Fluidization of particles is a complex hydrodynamics phenomenon. CFD Simulation of fluidized bed is widely employed in the chemical and refining industries to gain understanding and ensure design sufficiency. There are more than one way to perform this simulation. Eulerian-Eulerian methods treats the particles as a phase interpenetrating in to the fluid phase. Discrete element methods (DEM) treat the particles as discrete entities in a Eulerian-Lagrangian framework. Both methods provide answers with different computation requirement and the accuracy of the outcome. In this work, we will present a comparison between these two most commonly used methods within the same solver framework.

For solid phase, kinetic theory based granular model was used within Eulerian Multiphase (EMP) method and soft sphere approach was used within Discrete Element Method (DEM). In order to compare the methods for range of flow regimes and boundary conditions, two different test cases were simulated.

The first test case involves rectangular fluidized bed set-up announced as Small Scale Challenge Problem (SSCP-I) by the Department of Energy's (DOE) National Energy Technology Laboratory (NETL) in 2013. For this case the results of EMP and DEM are compared with available experimental data.

The second test case involves higher complexity geometry and boundary conditions and significantly larger number of particles. For this case recently introduced and validated DEM coarse grain model [1] is used for comparison with EMP model results. 

Both DEM and EMP simulations were done using STAR-CCM+ software developed by CD-adapco. This comparative study highlights outlines the guidelines for a choice between DEM and EMP for simulating dense gas-solid fluidized beds in industrial applications based on desired outcomes.

References:

[1] Mohit P. Tandon, Aditya U. Karnik, Simulation of rectangular fluidized bed with Geldart D particles, 10th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries, 2014

[2] Oleh Baran, Ashish Newale, Doran Greening, DEM simulations of industrial size fluidized bed using coarse grain model with particle size distribution, AIChE 2014