  Understanding and predicting the hydrodynamics of gas bubbles and
particle-laden phase in fluidized beds is essential for the successful design
and efficient operation of this type of reactor. In this work, we used
real-time magnetic resonance imaging (MRI) to investigate the effect of baffles
on gas bubble behavior and particle motion in a fluidized bed model with an
inner diameter of 190 mm. MRI time series of the local particle density and
velocity were acquired and used to study the size, number, and shape of gas
bubbles as well as the motion of the particle phase. The superficial gas
velocity was varied between 1 and 2 Umf . We found that baffles decreased the
average equivalent bubble diameter with a simultaneous increase in the total
number of bubbles. Moreover, baffles promoted bubble splitting and the
formation of air cushions below the baffles and decreased the average particle
velocity and acceleration in the bed. For two of the three investigated baffle
types, the particle velocity distribution became wider compared to the bed
without internal.
