Experimental Studies of Gas Permeability Through Isotropic Porous Materials in the Cubic System

The results of the experimental research on the assessment of the gas permeability of porous materials in relation to gas flow are presented. The tests involved materials with an isotropic gap-porous structure—for comparison, a model material such as sintered polyamide vs. a bed of polyethylene balls (a porous skeleton bed made of LDPE—polyethylene with a much lower density). The tests were carried out on specially prepared test stands, enabling measurements of gas permeability in relation to three flow orientations, related to symmetrical cubic samples. The measurement results practically do not depend on the flow direction on the permeability of the polyamide sinter and the polyethylene ball bed, which results from the isotropic internal structure. The permeability coefficient of this type of material was defined and the value of this coefficient in relation to the gas stream and the total pressure drop in the porous bed was experimentally assessed. The gas permeability characteristics are presented in relation to the apparent velocity in the bed, depending on the average gas flow direction XYZ (for polyamide: air (2.4–20.5) × 10⁻⁷ m², and nitrogen (2.7–22.9) × 10⁻⁷ m²; and, for LDPE: oxygen (0.112–0.235) × 10⁻⁷ m², and nitrogen (0.301–0.463) × 10⁻⁷ m². What is new in the article is the indication of the process issues of gas permeability, which were considered in terms of the scale (scale effect) of the hydrodynamics of gas flow through porous deposits. This is important for expanding our knowledge about the assessment of gas flow hydrodynamics in porous media, which has not yet been recognized for the development of a new generation of clean energy sources.