Details

Autor(en) / Beteiligte

• Tomadakis, Manolis
• Fuselier, Katie
• Almeer, Fahad
• Ferguson, Ashley
• Cowdrick, Victoria

Titel

Transport through random bimodal and multimodal fiber structures

Ist Teil von

• Chemical engineering science, 2020-02, Vol.212, p.115298, Article 115298

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2020

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• •Transport through bimodal and multimodal fibrous media is studied through simulations.•Analytical expressions are derived for the mean intercept length, validated numerically.•Tortuosity and formation factors are equal to those for unimodal media in most cases.•Permeability is obtained from that of unimodal media through a fiber dispersity factor.•Experimental permeability data of the literature support the theoretical predictions. Random walk simulation results are reported for the transport and structural properties of random bimodal fibrous media for a range of values of the porosity, relative fiber size, and relative fiber density. Analytical expressions are derived for the mean intercept length of random bimodal and multimodal fiber structures, and are validated through simulations. A fiber dispersity factor emerges from the derivations, accounting for the deviation of the mean intercept length of such structures from that of unimodal fiber beds of the same porosity. Tortuosity factors in all diffusion regimes for in-plane and transverse flow through bimodal fibrous media of moderate or high porosity are practically independent of the relative fiber size and density and equal to those reported earlier for beds of unimodal fibers. The same holds for the formation factor of such structures, accounting for the dimensionless effective bulk diffusivity, thermal and electrical conductivity, magnetic permeability, dielectric constant and refractive index. The dimensionless viscous permeability of bimodal and multimodal fiber structures of moderate or high porosity may be obtained from that of unimodal fiber structures through simple multiplication by the square of the dispersity factor. This result is in line with a multitude of experimental data of the literature.