Numerical simulations of gas–liquid flow in thermal sorption processes

• We carry out a hydrodynamic study of falling film absorbers.
• The performance prediction of sorption storage systems is in focus.
• Two geometries are considered, an inclined plane and two horizontal parallel tubes.
• Numerical simulations results for gas–liquid film-flows are compared with experimental data.
• The efficiency of thermal storage systems is characterized by the specific wetted area.

Thermal storage systems, used, e.g., for domestic heating, must be able to compensate the mismatch between supply and demand. The most efficient techniques for thermal storage are based on sorption storage processes. Usually in sorption, the adsorption process occurs in combination with a solid state adsorbent, whereas absorption takes place in a liquid/gas system. During such sorption processes the flow behavior of the carrier medium is crucial for the efficiency of a falling film absorber. In this work the hydrodynamics of the falling liquid film in two geometrical setups, namely on an inclined plane and over two horizontal parallel tubes, is studied. For the simulation the Eulerian–Eulerian model of the software ANSYS CFX and the interFoam application of the open source software OpenFOAM were used. The numerical results of the two geometries were compared with each other and also with existing data from literature to predict the performance of a sorption storage regarding the specific wetted area and the needed height for gravity driven film absorption.