Computational Fluid Dynamics (CFD) Modeling of 3D Printed Spacers based on TPMS Architectures for Applications in Water Treatment

Abstract

The global water crisis necessitates advancements in desalination technologies, with membrane distillation (MD) showing significant potential. However, its widespread adoption is hindered by challenges such as low flux and membrane fouling. This thesis presents a novel approach to enhance MD performance through advanced computational fluid dynamics (CFD) modeling and innovative feed spacer designs based on Triply Periodic Minimal Surfaces (TPMS). A three-dimensional CFD model was developed to simulate flow in spacer-filled Direct Contact Membrane Distillation (DCMD) channels. This model facilitated extensive parametric studies and virtual prototyping, significantly reducing development time and costs compared to traditional experimental methods. Initial studies with the Fischer-Koch S TPMS-based spacer showed doubled flux compared to an empty channel and 13% improvement over conventional spacers, albeit with increased pressure drop. Building on these findings, a novel transient CFD model integrating nucleation theory and population balance equations was developed to analyze gypsum scaling kinetics. CFD provided non-intrusive visualization of scaling throughout the flow channel, offering insights difficult to capture experimentally. The Gyroid spacer outperformed commercial designs with 63% higher initial flux, delayed scaling onset, and reduced scalant-mass density. The exceptional flexibility offered by TPMS topologies, rooted in their mathematical foundations, provides unprecedented control over structural parameters. Design of experiment (DoE) and machine learning (ML) tools were integrated with CFD to optimize the Gyroid TPMS spacer geometry, with a focus on modifying flow patterns and enhance anti-scaling capabilities. The optimized Gyroid spacer exhibited significant improvements, including an ~9-fold increase in minimum wall shear stress compared to the base case. Furthermore, it achieved a final flux ~ 38.5% higher than that of the base case at the end of the 16-hours operation. The methodology developed shows promise for extension to other optimization objectives in future research, paving the way for next-generation desalination systems in water-scarce regions and industrial applications.

Date of Award	9 Dec 2024
Original language	American English
Supervisor	Hassan Arafat (Supervisor)