Effect of inlet flow type on fluidization of gas-solid fluidized beds by using coupled CFD-DEM

In this paper, the effect of inlet flow type on fluidization of solid-gas fluidized beds was studied by using coupled CFD-DEM simulations. Spherical particles were selectedfrom Geldart group B. Uniform and pulsed flow were injected at the bottom of a rectangular bed. Two cases of pulsed flow were considered: sinusoidal. and relocating. The fluidized bed behavior discussed in terms of minimum fluidization velocity, pressure drop, bubble formation, bed expansion, particles velocity. gas-solid interaction andparticle contact forces. According to different conditions, the results indicated that pulsed flows decreased the minimum fluidization velocity by up to about 30%. Theinfluence of the pulsation amplitude on minimum fluidization velocity was more significant than that of the pulsation frequency. The pulsed flow increases the bed expansion and particle velocity, while decreases the pressure drop and interaction force. As the pulsation frequency increases, the pressure drop and gas-solid interaction force increase, although size of the bubbles a11d bed expansion decrease. ln the sinusoidal flow, the velocity and contact force of particles are initially increased by frequency and in larger frequencies are decreased.

Keywords:

Gas-solid flows , Fluidized beds , Fluidization , CFD—DEM , Pulsed flow