(251a) Simulated Pressure Drop in Structured Packing: Experimental Validation and Impact of Packing Geometry

Computational fluid dynamics (CFD) simulations of single-phase flow through structured packing were performed using STAR-CCM+. Pressure drop data using a detailed geometry generated via X-ray CT compared favorably to experimental results. The steady-state data showed the Realizable k-ε turbulence model yielded better predictions than the SST k-ω model.

With a validated model, multiple small-scale, periodic geometries were utilized to evaluate the impact of fundamental packing geometry on overall pressure drop. Corrugation angle, packing specific area, and channel dimensions (e.g. channel height and channel opening angle) were varied with F-factors ranging from 0.5-3.0 Pa^0.5. The impact of density and viscosity was examined.

Pressure drop contributions were broken into two terms: a pipe flow (wall friction) term and a mixing/shear layer term. The pipe flow term was accounted for by running simulations of vertical channels. The pipe flow term was non-dimensionalized using the hydraulic diameter and diagonal (effective) velocity through the triangular channels.  The shear pressure drop term was non-dimensionalized using the channel side length and horizontal velocity. The regressed model predicted the CFD data with an average error of 5% and a maximum error of 20%.

The mixing layer term was found to account for over 80% of the pressure drop in packings with a corrugation angle of 45° and over 60% of the pressure drop in packings with a corrugation angle of 60°. The shear pressure drop was also found to be a strong function of the packing channel opening angle. For a constant specific surface area and corrugation angle, pressure drop was maximized with a channel opening angle of 90°.