Antiphase alternating-pulse fluidized bed for improving the fluidization quality: An Eulerian–Eulerian study

Abstract

To address poor radial mixing in conventional pulsed fluidized beds (PFB), a novel antiphase alternating-pulse fluidized bed (AAPFB) is proposed to improve the fluidization quality by combining a well-designed air distributor and a non-steady-state gas intake technique. Detailed analysis of flow field differences among uniform flow fluidized bed (UFB), PFB, and AAPFB was conducted through numerical simulations, with a particular focus on examining variations in dispersion coefficients, elucidating the mechanism of the regulation of the flow fields by antiphase alternating pulsed airflow. The study also explored the modulation of inlet waveform, pulse frequency and vibration amplitude on flow characteristics. Results indicated that (i) AAPFB achieves uniform particle disturbance, significantly enhancing gas and particle dispersion; (ii) Rectangular flow improves particle distribution more than sinusoidal and triangular flows; and (iii) A 1 Hz pulse frequency and 0.3u_m amplitude optimally balances flow disturbances and bubble dynamics, resulting in superior dispersion for gas and particles.