Co-authors​ :

 Mostafa NIKZAD (AUSTRALIA), Joao MACHADO (PORTUGAL), Md Abdus SATTAR (AUSTRALIA), Stephan LOMOV (BELGIUM), Masoud BODAGHI (LUXEMBOURG) 

Estimation of permeability of porous media dates back to Henry Darcy [H. Darcy, Les Fontaines Publiques de la Ville de Dijon (Victor Dalmont, 1856)], and its knowledge is essential in the Liquid Composite Moulding (LCM) family of composite manufacturing processes [1]. Despite the apparent simplicity of permeability measurements, the literature has reported a wide range of scattered data; the sources of which can be attributed to the precision of the experiment or simulation as well as the reinforcement textile's inherent variability. In addition, as permeability measurement is not standardised, the reported permeability values show a large scatter between different methods and laboratories. This source is being addressed in a series of international permeability benchmark exercises [2-3]. Most recently, after several decades of involvement in benchmarking activities that led to a standardization initiative, an ISO standard for in-plane permeability has been published [4]. A key underpinning criterion is the development of a standard reference medium for the calibration of permeability rig set-ups. Recently, the authors successfully manufactured a textile-like porous medium. Employing statistical analysis based on 20 permeability measurements using the same set-up, they observed a coefficient of variation of less than 2%. This remarkable precision can be attributed to the effective utilization of Stereolithography (SLA) for manufacturing the reference medium with tolerances well below 2% of the nominal thickness of the mould. The results confirm the effectiveness of this innovative approach in eliminating the inherent source of variability typically found in real textile samples [5].
In this work, a detailed simulation study of fluid flow through a 3D printed reference medium was conducted using ANSYS Fluent, 2021 R1 and R2 based upon the surrogate CAD model replicated in PTC Creo Parametric 6.0. Two specific cases were investigated numerically. In the first case, different pressure was applied at the inlet of both the small and large channels and the effect of the pressure on the permeabilities was calculated as well as the pressure and velocity profiles were observed. In the second case, different pressure and velocity boundary conditions were applied at the inlet of the channel and their effect on the permeability, the pressure and velocity inside the channel were investigated in both actual size and the channel with reduced width by 5% and 10%. Permeability throughout the length of the channels, vertical and horizontal velocity profiles, and flow-developing zones are noted. The permeability results obtained from the simulation of the CAD models are compared and contrasted with the experimental data and MicroCT scan results.
ACKNOWLEDGEMENT
Both ANSYS versions and CREO Parametric 6.0 were academic licenses made available by Swinburne University of Technology as per the agreement with local ANSYS vendor Leap Australia and PTC, respectively.