Surface tension effects on the absorption process in a spiral tubular absorber working with LiBr-H2O couple

In this work, the surface tension effect is inspected in the modeling of absorption process of water vapor by a LiBr solution in a spiral tubular absorber of a double effect absorption chiller. We have considered the wettability of the absorber tubes and the real hydrodynamics of the liquid solution which reveals the presence of three different flow regimes: a falling film region existing on the tube in which circulates the cooling water, a droplet formation region at the tube's bottoms and a droplet free fall region between the spaced tubes. The equations governing the coupled heat and mass transfers are established for each flow regime. The numerical simulation has illustrated the effect of surface tension on the evolution of the absorption parameters along the absorber tubes compared to the case when the surface tension contribution is neglected. The validity of the model was improved using experimental data performed on the double effect absorption chiller. (C) 2015 Elsevier Masson SAS. All rights reserved.