CFD-DEM study of the effects of direct current electric field on gas-solid fluidization
Electric fields can make significant impact on meso-scale structures, such as bubbles and clusters, in gas-solid fluidized beds. In this work, a 2-D gas-solid fluidized bed coupled with a DC electric field is established, and numerical simulations are carried out based on CFD-DEM method. Electric-field induced forces are modeled based on a revised point-dipole approximation by considering local-field effects and multipolar interactions. The reason for bubble size reduction and clusters formation is investigated in detail from the perspective of particle motions and forces, respectively. Simulated results show that formation of chains suppress the vortex motion of particles and result in the elimination of bubbles. Although particle-particle interactions are repulsive in the direction normal to the electric field, particles are observed to attach to each other along an oblique angle to form a braided multi-particle chain. Moreover, distributions of particle concentration and velocity become more homogeneous as the field strength increased.
Keywords: Electric field, Gas-solid fluidized bed, CFD-DEM, Numerical simulation