Three-dimensional effects on carbon capture in wavy falling films
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Wave evolution in thin-film flows is highly relevant for heat and mass transfer applications, such as CO2
capture
in falling film absorbers. To develop a detailed understanding of potential enhancement mechanisms associated
with the evolution of three-dimensional (3D) waveforms, we perform 3D direct numerical simulations
of passive scalar transport in laminar-wavy film flows, using a hybrid front-tracking/level-set method to
accurately resolve interfacial features. CO2 absorption is greatly enhanced in the presence of interfacial waves
with the liquid-side mass transfer coefficient increasing tenfold relative to that of a flat film for the highest
film Reynolds numbers (𝑅𝑒) studied. This is primarily due to changes in interfacial and internal flow dynamics
rather than an increase in the gas-liquid interfacial area. The recirculation region present in the leading and
trailing fronts of the 3D waves intensifies mass transfer, and their effectiveness increases with 𝑅𝑒. At low 𝑅𝑒,
there is a film region beneath the wavy interface, which remains relatively undisturbed where mass transfer
is dominated by diffusion. The introduction of structured substrates to promote mass transfer under these
conditions is recommended. The visco-capillary ripple region, which precedes the leading and trailing fronts for sufficiently high 𝑅𝑒, provides a relatively high degree of spanwise advection, with the mean spanwise velocity
magnitude reaching around one-quarter that in the streamwise direction. This underscores the importance of solving the fully-3D problem as these effects do not have a two-dimensional analogue.
capture
in falling film absorbers. To develop a detailed understanding of potential enhancement mechanisms associated
with the evolution of three-dimensional (3D) waveforms, we perform 3D direct numerical simulations
of passive scalar transport in laminar-wavy film flows, using a hybrid front-tracking/level-set method to
accurately resolve interfacial features. CO2 absorption is greatly enhanced in the presence of interfacial waves
with the liquid-side mass transfer coefficient increasing tenfold relative to that of a flat film for the highest
film Reynolds numbers (𝑅𝑒) studied. This is primarily due to changes in interfacial and internal flow dynamics
rather than an increase in the gas-liquid interfacial area. The recirculation region present in the leading and
trailing fronts of the 3D waves intensifies mass transfer, and their effectiveness increases with 𝑅𝑒. At low 𝑅𝑒,
there is a film region beneath the wavy interface, which remains relatively undisturbed where mass transfer
is dominated by diffusion. The introduction of structured substrates to promote mass transfer under these
conditions is recommended. The visco-capillary ripple region, which precedes the leading and trailing fronts for sufficiently high 𝑅𝑒, provides a relatively high degree of spanwise advection, with the mean spanwise velocity
magnitude reaching around one-quarter that in the streamwise direction. This underscores the importance of solving the fully-3D problem as these effects do not have a two-dimensional analogue.
Date Issued
2026-03-01
Date Acceptance
2026-01-17
Citation
International Journal of Multiphase Flow, 2026, 197
ISSN
0301-9322
Publisher
Elsevier BV
Journal / Book Title
International Journal of Multiphase Flow
Volume
197
Copyright Statement
© 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published
Article Number
105624
Date Publish Online
2026-01-19