Numerical simulation of carbon dioxide (CO2) absorption and interfacial mass transfer across vertically wavy falling film

Jianguang Hu, Xiaogang Yang, Jianguo Yu, Gance Dai

Research output: Journal PublicationArticlepeer-review

23 Citations (Scopus)

Abstract

The process of CO2 absorption in many currently used chemical devices can be typically characterised and analysed by mass transfer across a thin falling film gas-liquid interface. There is still a lack of general predictability of the transfer quantity based on the basic hydrodynamic parameters involved in such mass transfer processes, and certain important phenomena associated with the transfer still remain unexplained. A novel concept that utilises the correlation between the vorticity neighbouring the falling film gas-liquid interface and the gas concentration to characterise CO2 absorption mass transfer by the falling film is proposed in this work. Numerical simulations using a volume of fluid (VOF) approach were performed for a vertical falling film arrangement. The wave hydrodynamics and the associated mass transfer are discussed, and the numerical results are compared with the existing experimental empirical relationships. In particular, the mass transfer across the falling film interface is interpreted as the passive scalar entrapment and entrainment by the interfacial vortices. The numerical simulation clearly indicates that two types of vortices exist: wall-bounded vortices associated with primary shear in the falling film and interfacial vortices associated with weaker shear in the vicinity of the interface. The numerical simulation reveals that mass transfer across the falling film is highly correlated with the interfacial vorticity Ωi, thus indicating the use of cΩi- is able to characterise the mass transfer across the falling film gas-liquid interface.

Original languageEnglish
Pages (from-to)243-253
Number of pages11
JournalChemical Engineering Science
Volume116
DOIs
Publication statusPublished - 6 Sep 2014

Keywords

  • Carbon dioxide absorption
  • Falling films
  • Hydrodynamics
  • Interface
  • Mass transfer
  • Vorticity

ASJC Scopus subject areas

  • Chemistry (all)
  • Chemical Engineering (all)
  • Industrial and Manufacturing Engineering

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