Crossflow Microfiltration Shear Calculator

Downstream bioprocessing & cell harvesting: Calculate hollow fiber wall shear rate (γ_w), Transmembrane Pressure (TMP), gel polarization layer, and cell lysis limits.

Hollow Fiber Module & Hydrodynamics

Fiber Inner Diameter d_i (mm): Standard lumen: 0.5 mm or 1.0 mm

Number of Fibers in Module (n): Total parallel hollow fiber tubes

Feed Flow Rate Q_feed (L/min): Total recirculating retentate loop

Cell Suspension Type:

Inlet Feed Pressure P_feed (bar): Filter inlet gauge pressure

Retentate Pressure P_ret (bar): Filter retentate exit pressure

Permeate Pressure P_perm (bar): Filtrate side backpressure

Filter Membrane Area (m²): Effective filtration surface

Lumen Shear & Separation Driving Force

Wall Shear Rate (γ_w)

Transmembrane Pressure (TMP)

Lumen Linear Velocity (v_lumen)

Mean axial crossflow velocity

Axial Pressure Drop (ΔP_axial)

P_feed - P_ret

Flow per Fiber (q_single)

mL/min per hollow fiber lumen

Expected Permeate Flux

LMH (L / m² / hour)

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Frequently Asked Questions

What is the role of wall shear rate in hollow fiber cell harvesting?

In hollow fiber microfiltration, crossflow sweeping generates shear stress at the inner lumen wall (γ_w = 8v / d_i). This shear lifts deposited cells back into the bulk retentate stream, preventing severe membrane fouling (cake buildup) while ensuring the velocity gradient does not exceed the mechanical lysis threshold of sensitive mammalian cells.

What is Transmembrane Pressure (TMP) and how is it controlled?

Transmembrane Pressure is the net pressure driving permeate liquid through the porous membrane wall: TMP = [(P_feed + P_retentate) / 2] - P_permeate. It is controlled by adjusting the feed pump speed and throttling the retentate pinch valve.

Why are 1.0 mm or larger lumens preferred over 0.5 mm for mammalian cell cultures?

Mammalian cells (CHO, hybridomas) are large (12–20 µm) and membrane-bound without a rigid peptidoglycan cell wall. Narrow 0.5 mm lumens generate high shear rates at modest crossflow rates, causing cell rupture. 1.0 mm lumens accommodate higher volumetric recirculation rates at low, gentle shear rates (<2,500 s⁻¹).