Numerical simulation of pressure fluctuation in gas-solids agitated fluidized bed

Agitators were introduced to gas-solids fluidized beds to improve fluidization performance and scrape sticky particles from internal bed wall. Numerical simulations based on the computational fluid dynamics (CFD) method were carried out to predict bubble behavior in the agitated fluidized bed. The Euler-Euler two-fluid model and the kinetic theory of granular flow were incorporated to describe the gas-solids flow, whist the multiple reference frame method was applied to deal with the rotation of agitator. The numerical models were validated by bed pressure drop and its fluctuation obtained in the experiment. The bubble behavior and fluidization performance were investigated in terms of pressure fluctuation. The results indicated that the amplitudes of pressure fluctuation and its power spectrum were reduced by increasing agitation speed of frame impeller, while dominating frequency had positive but inconspicuous correlation with agitation. The characteristics of pressure fluctuation showed that bubble size in the fluidized bed went down with a rise in agitation speed, which might lead to the transition from bubbling fluidization to particulate fluidization. © All Rights Reserved.