Hydrodynamic behavior of the falling-film over horizontal tubes under different distribution conditions

The flow behavior of the liquid film has a significant impact on the efficiency of heat and mass transfer in falling film type heat exchangers. It is essential to study the distribution of film thickness around the tubes. This paper presents a numerical investigation of falling-film over inline horizontal tubes. The objective of this study is to compare the film thickness under different liquid distributor sizes. The simulations are carried out with two inline horizontal tubes using ANSYS Fluent. The Volume of Fluid (VOF) technique is implemented in this analysis to identify the interface between the two phases. The spreading of the falling film over the inline horizontal tubes at different liquid distributors namely Dist1, Dist2, Dist3, Dist4, and Dist5 was observed. Results illustrated that flow patterns near the upper and lower stagnation zones of the horizontal tubes were shaped by the liquid distribution conditions. It is found that film thickness is affected by the size of the distributor. The results showed that the film thickness increases with the increasing size of the distributor. The present work helps as a reference to eliminate flooding and low wetting phenomena over the heat exchanger tubes.