Nanofiltration Membrane Fouling: Cake Layer & Flux Decline

Nanofiltration membranes reject dissolved organics, multivalent ions and colloids by size and charge, but every rejected particle that isn't swept away by the feed stream has to go somewhere — it piles up on the membrane face as a cake layer. This simulator renders a 3D feed channel where foulant particles are driven toward a nanofiltration membrane by transmembrane pressure while a tangential crossflow sweeps a fraction of them past; the particles that deposit build a visible cake whose growing hydraulic resistance is fed straight into the real resistance-in-series Darcy law, so permeate flux declines exactly as it would on a real skid. Tune feed concentration, applied pressure and crossflow velocity to find the trade-off between throughput and fouling rate, then trigger a backwash pulse — or switch on periodic auto-backwash — and watch the cake lift and flux recover, never quite to the clean-membrane baseline.