CFD Analysis of Falling Film Hydrodynamics for a Lithium Bromide (LiBr) Solution over a Horizontal Tube

Furqan Tahir, Abdelnasser Mabrouk and Muammer Koç
Additional contact information
Furqan Tahir: Division of Sustainable Development (DSD), College of Science & Engineering (CSE), Hamad Bin Khalifa University (HBKU), Education City, Doha 34110, Qatar
Abdelnasser Mabrouk: Division of Sustainable Development (DSD), College of Science & Engineering (CSE), Hamad Bin Khalifa University (HBKU), Education City, Doha 34110, Qatar
Muammer Koç: Division of Sustainable Development (DSD), College of Science & Engineering (CSE), Hamad Bin Khalifa University (HBKU), Education City, Doha 34110, Qatar

Energies, 2020, vol. 13, issue 2, 1-15

Abstract: Falling film evaporators are used in applications where high heat transfer coefficients are required for low liquid load and temperature difference. One such application is the lithium bromide (LiBr)-based absorber and generator. The concentration of the aqueous LiBr solution changes within the absorber and generator because of evaporation and vapor absorption. This causes the thermophysical properties to differ and affects the film distribution, heat, and mass transfer mechanisms. For thermal performance improvement of LiBr-based falling film evaporators, in-depth analysis at the micro level is required for film distribution and hydrodynamics. In this work, a 2D numerical model was constructed using the commercial CFD software Ansys Fluent v18.0. The influence of the liquid load corresponding to droplet and jet mode, and the concentration, on film hydrodynamics was examined. It was found that the jet mode was more stable at a higher concentration of 0.65 with ±0.5% variation compared to lower concentrations. The recirculation was stronger at a low concentration of 0.45 and existed until the angular position ( θ ) = 10°, whereas at 0.65 concentration it diminished after θ = 5°. The improved heat transfer is expected at lower concentrations due to lower film thickness and thermal resistance, more recirculation, and a higher velocity field.

Keywords: falling film; film thickness; CFD; horizontal tube; lithium bromide; LiBr; transient analysis; VOF (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View complete reference list from CitEc
Citations: View citations in EconPapers (4)

Downloads: (external link)
https://www.mdpi.com/1996-1073/13/2/307/pdf (application/pdf)
https://www.mdpi.com/1996-1073/13/2/307/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:13:y:2020:i:2:p:307-:d:306340

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().