Entropy generation in gas absorption into a falling liquid film

The study of mass transfer into falling films constitutes a significant aspect for numerous applications in the chemical technology and is considered the subject of many theoretical and experimental researches. Evaluating the second law of thermodynamics is one of the contemporarily used methods to determine the performances of an industrial process and to study various sources of irreversibility. Expressions of the liquid velocity, the gas concentration, the entropy generation rate as well as the main sources of irreversibility in the case of gas absorption (carbon dioxide) into a laminar falling viscous incompressible liquid film (water) without chemical reaction, are analytically derived and graphically presented and discussed.

► Entropy generation expression is developed, then analytically determined for the case of gas absorption into a falling incompressible viscous liquid film. ► Gas absorption by diffusion and by convection as well as viscous effects due to velocity gradient inside the liquid film are the basic parameters of the irreversibility.