Modeling the Gas Liquid Interface of Falling Film Reactors in Fully Developed Flow Regime

In falling film reactors, the time scale of reaction is typically faster than the time scale of the mass transfer; hence the overall efficiency of the reactor is limited by the rate of mass transport to the reactive interface, which in turn depends on the effective surface area between the liquid phase and the gas phase. Therefore, the performance of these reactors strongly depends on how well the wavy interface dynamics and their influence on the reactive transport are understood at the most fundamental level. In this work, we focused on the numerical analysis of the wavy interface for alternative liquid distribution strategies with Smoothed Particle Hydrodynamics (SPH). In particular, we investigated the flow development in the entrance region and how it evolves into a fully developed region. We also analyzed the film statistics by extracting the probability density functions of the local film thicknesses in both time and frequency domains. Comparisons between SPH simulations and the available literature confirmed that the deployed numerical solution methodology can capture the global interface dynamics. However, higher residence times must be computed to fully capture the complex local mixing patterns in the fully developed region, which cannot be captured with periodic boundary conditions.