Gas permeability in rarefied flow conditions for characterization of mineral membrane support

C. Savaro (1, 2) , J.P. Bonnet (1, 2) , M.V. Johansson (2, 3) , Pierre Perrier (2, 3) , Irina Martin Graur (3, 2) , P. Moulin (2, 1)

1 M2P2 - Laboratoire de Mécanique, Modélisation et Procédés Propres
2 AMU - Aix Marseille Université
3 IUSTI - Institut universitaire des systèmes thermiques industriels

Gas Permeability Measurement Technique (GPMT) has the advantage of being a non-destructive method, which is efficient in characterizing filtration membranes. Ceramic filtration membranes consist of successive layers of micro (support) to nano size (skin) pores. When gas flows through such a small scale structure, the molecular mean free path becomes comparable to the pore size. The Slip flow model, validated to describe the gas transport properties under rarefied flow conditions in a microchannel, is extended to porous media. The porous structure is modeled as a cluster of several identical cylindrical channels. By measuring the pressure drop ∆P at several different mean pressures, the pore radius and the porosity on square tortuosity ratio /τ 2 of the porous model structure that have the same flow property were estimated. Nomenclature G Geometric factor (m −1) H Effective length of hollow fiber (m) J Mass flux density (kg.s −1 .m −2) K Hydraulic conductivity (s) Kn Knudsen number L p Channel length / Gas path length through the porous media (m) N Channel number P Gas pressure (Pa) P 0 Pressure upstream the nozzle (bar) P 1 Pressure upstream the porous sample (bar) P 2 Pressure downstream the porous sample (bar) P c Nozzle critical pressure (bar) P m Mean pressure (Pa)

Keywords: Microporous media; Slip flow; Permeametry; Pore size

Domains: Engineering Sciences [physics]

C. Savaro, J.P. Bonnet, M.V. Johansson, Pierre Perrier, Irina Martin Graur, et al.. Gas permeability in rarefied flow conditions for characterization of mineral membrane support. European Journal of Mechanics - B/Fluids, 2020, 79, pp.44-53. ⟨10.1016/j.euromechflu.2019.07.005⟩. ⟨hal-02904990⟩