Portraying the Countercurrent Flow on Packings by Three‐Dimensional Computational Fluid Dynamics Simulations

Abstract

The design of packed columns requires the detailed description of the hydrodynamics on the surface of the packings. To analyze the local flow behavior of the liquid phase, a three-dimensional Computational Fluid Dynamics (CFD) model was developed that applies to the two-phase countercurrent flow on an inclined and flat plate. This model, based on the volume-of-fluid (VOF) method, considers the gravity, the surface tension and the drag force between the two phases. The development of such a model allows investigation of the influences of the liquid and gas flow rates on the flow behavior such as the film flow and the rivulet flow. A validation of the model was performed using data from the literature and from experiments conducted in this work. Simulation and experimental results demonstrate that the specific wetted area on the plate decreases with decreasing liquid load. Moreover, CFD simulations reveal that the presence of the countercurrent gas phase tends to increase the fluctuation and the thickness of the film flow, which is in accordance with experimental data. It also affects the flow behavior of the rivulet flow and changes the velocity profiles for both film and rivulet flow behavior. On the other hand, the simulation results indicate that CFD is a potent tool for analyzing and investigating the flow phenomena in chemical engineering.

CFD Modelling of CO2 Capture in a Packed Bed by Chemical Absorption

“…The flue gas enters the column at its bottom and an aqueous solution of MEA is released from the source located at the top of the porous region. These types of boundary conditions have been found to ensure the convergence of the solution (Xu et al, 2008).…”

Three-dimensional simulation of rivulet and film flows over an inclined plate: Effects of solvent properties and contact angle

“…Structured packing offers superior performance [3] with a large surface area per unit volume for mass transport and a high absorption efficiency while minimizing pressure drop [4]. Structured packed columns are also widely used in other chemical processing technologies such as distillation and liquid-liquid extraction [5][6][7]. The accurate design of such columns requires knowing essential hydrodynamic characteristics, such as, pressure drop and liquid holdup of the packing element [8].…”

Adaptive mesh refinement of gas–liquid flow on an inclined plane

“…However, the observed differences in film interface structure are minimal and so may not have a significant impact on the absorption of species across it. When considering counter-current gas flow it has been observed that this can cause an increase in the thickness and fluctuation of liquid films (Xu et al, 2008). We are currently running counter-current flow simulations to determine if these differences in interface contour are observed.…”