A mathematical model of falling film absorption of H2O by LiBr aqueous solutions which considers wavy regimes has been implemented. The model is semi-empirical, based on Navier Stokes equations together with energy and mass species simplified under the boundary layer hypotheses. The coupled equations are solved by means of finite difference method in a step by step procedure. The wavy profile is introduced by solving Free Surface Deflection Equation in each grid step, the smooth film thickness is recalculated in function of the amplitude value of the wave profile and the mass absorbed. In order to validate the model developed, a comparison is performed with a simple model based on empirical information for heat and mass transfer coefficients for laminar smooth a wavy regimes. Numerical results are compared between smooth thickness film and wavy profile.

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