Multifaceted Convergence Study for Evaluating Gas Diffusion Parameters of Polymeric Membranes

Naveen Daham Weerasekera, Siyua Cao

In this paper, gas transport properties of PTFE (polytetrafluorethylene) polymeric membranes are studied. We focused our work on three methods based on, Darcy’s pore flow model, Fick’s diffusion and numerical analysis. Effective diffusion coefficients obtained by Darcy’s and Fick’s laws are compared. In numerical analysis, simplified computational fluid dynamics model was created using virtual porous medium concept. Virtual porous media is generated by adding a momentum sink term in the governing equations of fluid flow. Diffusion process described by Darcy’s method is performed using transfer of clean air through the membrane under induced pressure gradients. Fick’s diffusion parameters are obtained based on trace compound (C₃H₈O) transport through the membrane under induced concentration gradients. Relatively high inertial permeability compared to viscous permeability (10²) are recorded in Darcy’s analysis. Also, effective diffusion coefficient obtained by Fick’s law shows 10^-2 decrement compared to the same obtained by Darcy’s pore flow model. From computational fluid dynamics (CFD) results, virtual pore flow model successfully demonstrated its soundness on analyzing membrane transport properties. 

https://dx.doi.org/10.31873/IJEAS.6.11.21