A representative mechanistic model of multisolute transport in low-flow hollow-fiber dialyzers for wearable artificial kidney-oriented design.

To support the analysis of compact hollow-fiber dialyzers operated under low-flow conditions relevant to wearable artificial kidney development, a mechanistic model of multisolute transport was developed. Unlike conventional homogeneous-membrane descriptions, the dialysis membrane was represented as a three-layer asymmetric porous structure. Within a continuum framework, pore-scale hindered diffusion, ultrafiltration-driven convection, and transmembrane hydraulics were coupled to describe diffusion-convection transport under low-flow conditions. Comparisons with manufacturer-stylein vitroclearance data from commercial low-flow dialyzers showed that the model captured the main clearance trends of representative solutes under selected operating conditions. Apparent resistance decomposition further suggested that, under the baseline condition and the present resistance definition, the apparent blood-side boundary-layer fraction increased with solute size, whereas the apparent intramembrane fraction decreased. Parametric analyses were further conducted to examine the effects of selected operating and geometric factors in this model. The proposed framework may support preliminary numerical screening and mechanistic interpretation of compact dialysis-module concepts under wearable artificial kidney-relevant low-flow conditions.