Reimagining the shape of porous tubular ceramics using 3D printing

Tailoring the shape of porous ceramic tubes can improve the performance of several processes by enhancing fluid mixing and mass transfer and reducing fouling. Ceramics are, however, difficult to fabricate in complex geometries by conventional manufacturing methods. In this work, Digital Light Processing 3D printing of an acrylatebased resin containing an organometallic titania precursor was used for the first time to produce ceramic tubes in novel sinusoidal and twisted shapes, optimized with Computational Fluid Dynamics (CFD). CFD simulations of water in the laminar flow regime inside and around the tubes indicated improved fluid mixing by formation of vortices and fluid recirculation, increase of wall shear stress and enhancement of vorticity. Composite tubular structures with a 10 cm height and a wide range of design parameters (wavelength, peak amplitude, twist angle) were printed with a high resolution of 50 mu m using resin containing 25% wt. titanium acrylate, while shorter structures could also be printed using 50% wt. titanium acrylate. The printed tubes maintained their sinusoidal or twisted shape after thermal post-treatment (de-binding and sintering) despite shrinkage of 35-45 % due to decomposition of the organic components of the starting material. The final sintered structures were made of pure titania and had a high porosity of 82 to 92 %. Overall, simulation-led design and 3D printing allowed for the production of porous ceramic tubes in unconventional shapes that have great potential to boost the efficiency of separation, contacting and catalytic processes.