Related Experiment Video
Updated: Aug 6, 2026

Curtain Flow Column: Optimization of Efficiency and Sensitivity
Published on: June 12, 2016
Enhanced dispersion in cylindrical packed beds
R S Maier1, D M Kroll, R S Bernard
1Army High Performance Computing Research Center, University of Minnesota, Minneapolis, MN 55415, USA.
Abstract:
The effective longitudinal dispersion constant, D(L)(eff), in cylindrical packed beds is larger than in the bulk due to the existence of radial inhomogeneities induced by the cylinder walls. For dense random packed beds, D(L)(eff) can be several times larger than the bulk value, even for arbitrarily large cylinder radius, R. The time-scale for attaining asymptotic dispersion rates in a cylindrical geometry is neither the convective nor the diffusive time-scale, but rather D(T)/R(2), where D(T) is the bulk transverse dispersion rate. Similar effects are predicted for packed beds confined in ducts of any cross-sectional geometry. The case of a rectangular duct, compared with an infinite slit, provides an intuitive model for the influence of walls in the limit as R goes to infinity.
Related Concept Videos
Diffusion on Chromatography Columns
Longitudinal diffusion occurs when the solute molecules in the mobile phase diffuse from the more concentrated center of the chromatographic band to the more dilute regions on either side, both towards and against the flow direction. This...
Column Efficiency: Plate Theory
A higher number of theoretical plates signifies better column efficiency and improved separation capabilities. Plate height affects bandwidth and separation quality; it is inversely...
Column Efficiency: Rate Theory
During elution, a solute molecule experiences numerous transitions between stationary and mobile phases, exhibiting irregular residence times in...
Optimizing Chromatographic Separations
Band broadening refers to spreading solute bands as they travel through the column. This broadening can impact resolution. Plate height (H) represents the length required for one theoretical plate. A lower plate height corresponds to...
Gas Chromatography: Types of Columns and Stationary Phases
For an analyte to remain on the column for a sufficient amount of time, it must exhibit some level of compatibility (or...
Steady, Laminar Flow in Circular Tubes

