Effect of liquid flux on wetting behavior in slender trickle bed reactors: A particle-resolved direct numerical simulation study

Slender trickle beds play a crucial role in various industrial processes involving gas-liquid-solid systems. Understanding the wetting characteristics is vital for optimizing their performance and efficiency. In this study, we employ a particle-resolved Computational Fluid Dynamics approach combining the Volume of Fluid (VoF) method for gas-liquid interactions and a second-order implicit Immersed Boundary Method (IBM) for fluid-solid interactions. The particle wettability is modeled by imposing a contact angle boundary condition at the gas-liquid-solid interface. The impact of the liquid flux on the wetting patterns and the rate of liquid penetration depth within the slender trickle bed is studied. The results show two main mechanisms of penetration through the bed: gravitation and inertia driven. The penetration of the liquid in the bed is driven by gravity when the liquid flux is low and the inertia is diminished in the top of the bed. This results in enhanced wetting from the onset of the penetration. If the inertia is high (high liquid flux), the initial liquid penetration is fast and spreading in the bed only occurs after full penetration of the bed. • Investigation of the wetting characteristics in slender trickle bed reactors. • Using a combined Volume of Fluid and Immersed Boundary method. • Wetting phenomena included via a static contact angle implementation. • Wetting initially dominated by inertia, while in later stages gravitational forces dominate. • Two different wetting characteristics obtained, which depend on the liquid flux.