ENGINEERING JOURNAL CHIANG MAI UNIVERSITY

Volume 26, No. 02, Month AUGUST, Year 2019, Pages 231 - 242

Simulation of a fluidized bed characteristics using dem-cfd coupling

Preeda Prakotmak and Sathaphon Wangchai

Abstract Download PDF

This paper presents a coupled multiphase computational fluid dynamics and discrete element method (CFD–DEM) approach to simulate the behavior of fluid–particle interactions and flow characteristics of fluidized bed. The motion of discrete particles with ellipsoidal particle is described by dense discrete particle model (DDPM) on the basis of Newton’s laws of motion applied to individual particles and the flow of continuum fluid by the CFD based on the local averaged Navier-Stokes equations. The influence of inlet air velocity on the particle motion and collision behavior is investigated. Here, the motion of individual particle is based on the contact force between particles and the fluid force acting on the particles. Simulation results showed that minimum fluidization velocity was 1.65 m s-1 and pressure drops increased with increases in the number of particles. Higher superficial flow velocities gave rise to larger and more plentiful bubbles throughout the bed which led to higher rates of mixing. The particles were observed to be well-mixed after 2 s of fluidization. These observations have achieved a general understanding of phenomena which take place inside the bed during fluidization.

Keywords

CFD, DEM, Fluidized bed, Multiphase flow

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