AIChE Journal, Vol.54, No.3, 614-626, 2008
Two-phase flow in structured packings: Modeling and calculation on a macroscopic scale
A model is presented that allows calculating the macroscopic flow field of countercurrent two-phase flow in strongly anisotropic porous structures. It is applied to corrugated structured packings. All flow field variables and packing properties are averaged over the volume of an elementary cell. The anisotropic gas flow resistance is derived from measurements and from separate CFD calculations on 3D-X-ray CT scans. The liquid's flow resistance is calculated using an analytical model of liquid film flow on an inclined plate. Liquid flow along both preferential flow directions is represented by two separate phases, in order to consider horizontal forces despite their symmetry. Gas-liquid momentum transfer above the loading point is included. The macroscopic flow field is calculated for a 288 mm I.D. column containing four packing elements. Liquid spreading from a point source, for uniform irrigation, increased hold-up at the packing elements' joints and pressure drop are tested against experimental results. (c) 2008 American Institute of Chemical Engineers.
Keywords:CFD;structured packing;two-phase flow;elementary cell model;anisotropic pressure drop;X-ray;tomography