OSN simulator — CentrivaLab

Cartridge & Rotor

Cartridge

Nominal feed volume: 13 mL

Rotor

Feed volume

22.5 mL

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r_m = — mm r_s = — mm

Membrane & feed-surface radii set by the chosen tube + rotor (ΔP = ½ρω²(r_m²−r_s²)).

Solvent

Mixture with water

x_org 100 mol %

Mole fraction of the organic solvent (100 % = pure solvent). Viscosity from NIST-fitted Redlich–Kister laws; see the guide.

Temperature

T 25 °C

Density is taken at 25 °C (varies < 1 % over ±15 K); viscosity follows T.

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Solute

Solute type

Molar mass M (g/mol)

Override estimated properties

Leave blank to use the estimate. Measured values are always better.

Partial specific volume v̄ (cm³/g) Diffusivity D₀ (10⁻¹⁰ m²/s) Intrinsic viscosity [η] (mL/g) Number-average M_n for the osmotic pressure (g/mol) Osmotic 2nd virial A₂ (mol·m³/kg²)

Feed concentration C_A0

C₀ 10 g L⁻¹

Log scale 0.05–50 g/L

Solute permeability B

B 0.1 LMH

B sets the intrinsic rejection R_int = J_v/(J_v+B); use your own membrane data.

Comparison technology

Compare O-CMF against

Stirrer Speed

RPM 200 rpm

⟨τ⟩ — Pa

Range 100–1000 rpm (typical working range). ΔP same as O-CMF. The shear-stress slider is linked to the speed: move either one.

References:
• Colton & Smith (1972): Sh = 0.285 × Re^0.567 × Sc^0.33
• Koutsou & Karabelas (2012): Stirrer diameter 21 mm, geometry & assumptions; mean wall shear stress ⟨τ⟩ = 0.85 Re^0.49 μω (Eq. 7), Re = ρωR²/μ, R = 16.5 mm

Outside the validated range.

CP factor Γ vs J_v

ΔP 10 bar

Log scale 0.01–100. Five illustrative solvent permeances (0.3 → 30 LMH/bar; enter your own membrane's B above), toggle below. Green band: reliable window (Γ < 0.20). Dots: operating point at the specified ΔP.

Solute passage (1−R) vs J_v

Solid line: R_int(J_v) = J_v/(J_v+B). At the operating ΔP, each class operates at a different J_v: open circle = R_int, filled = R_obs. The gap between them shows the CP correction — larger for classes that require lower RPM.

Model: Geraldes V., Fan H., Yang M., Rodrigues M., Elimelech M. — "Predicting concentration polarization in Ortho-Centrifugal Membrane Filters for NF/RO membrane screening." Preprint under review, Journal of Membrane Science (2026). The correlation and the solver are those of the device-comparison page; here the thermo-physical properties are those of the OSN property guide (solvent density and viscosity from Choupo/ChemSep and NIST-fitted laws, solvent–water mixtures, solute v̄, D, [η] estimated unless you enter measured values), and the density of the solvent enters the ΔP–rpm conversion. The correlation was validated for aqueous systems and PEG 35 kDa in water; its use in organic solvents is an extension, not yet validated against OSN data. Correlation k_c/U* = 0.261 𝒢^1/4 Sc^−1/4, with the finite-permeation closure Ξ(φ) of Geraldes & Afonso (2006), Γ = R_int φX / (1 + (1 − R_int) φX), X = (1 + 0.26 φ^1.4)^1.7, exact in R_int — used for every solute and device, since film theory (valid only for φ ≲ 1.5) is a special case of it. In the O-CMF, ν and D are evaluated at the film concentration ½(c_m + c₀). In the stirred cell and the spiral-wound module (forced convection) the correlations keep the bulk properties and k_c is multiplied by the weak viscosity correction (ν_m/ν₀)^−0.075 found in the reconstructed radial cross-flow cell (36 runs); evaluating a Re^0.875Sc^0.25 law at the film concentration would over-correct. Validated against DNS for Sc ∈ [700, 2200] and 𝒢 ∈ [7×10⁻⁹, 5×10⁻⁶] (mean relative deviation ~7%, maximum ~22%), and against twelve reconstructed PEG 35 kDa ultrafiltration experiments in the O-CMF (Pereira, MSc thesis, IST 2026; Sc ≈ 3×10⁴, Γ 2–66, φ 1.4–7, within ±20 % in Γ). The five solvent permeances are illustrative and imply no particular membrane; enter your own B (and compare with your own permeance) to read off R_int.