As the static bed height increases, the quantity (bed weight) of solids increases, which obviously requires more fluid quantity and energy to swirl fluidize the solids, and hence increased fluid
velocities as shown in Fig. 6. For a given set of conditions, as the fluid inlet size increases, the fluid jet velocity decreases and the momentum of gas jet also decreases. So, higher flow rates would be required to achieve swirling with larger diameter fluid inlets as shown in Fig. 7.