Flux

Flux (J) expresses the volumetric flow rate through a unit area of filtration medium, typically in L/m²·h or m³/m²·s. It is the central parameter linking hydraulic load, permeability, and energy consumption. In Darcy-type models, flux depends on pressure difference, viscosity, and total resistance (medium + cake). Constant-flux operation holds J fixed by adjusting pressure; constant-pressure operation allows J to fall as the cake builds. Engineers define design flux ranges that balance throughput with manageable ∆p and fouling rates. Monitoring flux trends over time supports early maintenance and performance benchmarking across filter media or process changes.