Absorption of steam bubbles in lithium bromide solution

Philip Donnellan, Kevin Cronin, William Lee, Shane Duggan, Edmond Byrne

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Absorption heat transformers are thermodynamic cycles that are capable of recycling waste heat energy by increasing its temperature. One of the most important unit operations in a heat transformer is the exothermic absorption of water vapour into a solution of choice at a higher temperature. Bubble columns are potentially an efficient means of achieving this. An experimental analysis is conducted which examines the absorption of single steam bubbles into a concentrated aqueous lithium bromide solution. The bubbles are tracked using a high speed camera, and their rate of absorption is modelled using a simple ordinary differential equation model. Accurate model predictions are obtained when oscillating bubble Nusselt and the Sherwood number correlations are utilised. The proposed model is capable of describing 96% of the observed experimental variability. Very large mass transfer coefficients of approximately 0.0012. m/s are obtained, which is higher than any previously reported values used in heat transformer absorber design.

Original languageEnglish
Pages (from-to)10-21
Number of pages12
JournalChemical Engineering Science
Volume119
Early online date5 Aug 2014
DOIs
Publication statusPublished - 8 Nov 2014
Externally publishedYes

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