On the use of 3D-printed flow distributors to control particle movement in a fluidized bed

3D-printing has emerged as a revolutionary tool for the rapid-prototyping of both conventional and novel products. Its use can foster innovative solutions to engineering challenges that previously would have been considered impractical. We propose the manipulation and control of multiphase systems (e.g. fluidized bed bioreactors) as one such use. The article presented investigates the particle flow and mixing within a fluidized bed induced by novel additive manufactured flow distributors. The fluidized bed is designed for adherent cell expansion on 3 mm diameter calcium alginate macrocarriers. Particle tracking was employed to assess the influence of flow channel angle and direction upon the radial flux of the carriers within the vessel. Uni-directional angled (45°) flow channels generated swirling fluidization of the macrocarriers; increasing particle radial velocities by up to 5.2 times (compared to their vertical flow channel counterparts) at a liquid superficial velocity of 0.0047 m/s. Swirling fluidization also generated particle bed heights up to 52% higher than vertical flow channels. Bi-directional flow channels improved the spatial uniformity of particle radial velocity. In addition, the angular flow channels generated axial velocity gradients that facilitate fluctuations in the height of fluidized particles, thus counteracting elutriation. Finally, lower liquid flow rates and interstitial velocities were required to mix the particles, thus leading to lower hydrodynamic stresses introduced into the system. The introduction of multi-directional flow channels provides novel options to the design and use of flow distributor technology. We foresee additional advancements in chemical engineering product design utilizing additive manufacturing to manipulate multiphase flows.