Mass transfer intensification in laminar flow using wall-mounted ribs: A CFD and experimental study

Abstract

This study investigates the enhancement of mass transfer in laminar duct flow using wall-mounted ribs acting as turbulence promoters. Three rib geometries, semicircular, triangular, and rectangular, were evaluated under varying flow velocities using computational fluid dynamics (CFD). Multiple models (laminar, low-Re k-ε, k-ω SST, and Spalart–Allmaras) were tested to simulate flow separation and near-wall behavior. To validate the CFD predictions, an experimental setup employing the diffusion-controlled dissolution of copper in acidified dichromate was used. The Spalart–Allmaras model showed the best agreement with experimental results for triangular and rectangular ribs, while the laminar model was more accurate for the semicircular case. Results revealed that triangular ribs provided the highest mass transfer enhancement, followed by rectangular and semicircular ribs. Dimensionless correlations were developed for the Sherwood number as a function of Reynolds number, rib geometry, and pitch, offering useful tools for improved design and optimization of ducts, membrane systems, and process equipment where efficient mass transfer is critical.