A porous media model for CFD simulations of gas-liquid two-phase flow in rotating packed beds

X Lu,P Xie,D.B Ingham,L Ma,M Pourkashanian

doi:10.1016/j.ces.2018.04.074

Abstract

The rotating packed bed (RPB) is a promising advanced reactor used in industrial gas-liquid two-phase reaction processes because of its high phase contact efficiency and mixing efficiency. Investigation of RPBs using CFD simulations will improve the understanding of physical behaviours of gas and liquid flows in such reactors. Currently, CFD simulations on the RPBs only focus on the volume of fluid (VOF) method. However, the VOF method is not suitable for simulations of pilot-scale 2D and 3D RPBs due to the limitations in computer resources, while the Eulerian method using a porous media model is a promising alternative method but it is rarely reported. The reason is that there are no suitable porous media models that accurately describe the drag force between the gas and liquid, the gas and solids and the liquid and solids due to the high porosity and the stacked wire screen packing used in RPBs. Therefore, the purpose of this paper is to propose a new model for modelling RPBs. The new proposed model is based on the Kołodziej high porosity wire screen one-phase porous media model. In this work, two experimental counter-current gas–liquid flow cases from the literatures have been used for validating the CFD simulation results. Finally, the new model has been compared with the current porous media models for traditional spherical or structured slit packed beds, which are the Attou, Lappalainen, Iliuta and Zhang models. The simulation results show that the proposed new model is the most appropriate and accurate model for the simulation of RPBs among all the models investigated in this paper.

Highlights

The rotating packed bed (RPB) was first proposed and developed by Prof
We develop a new two-phase porous media model for a wire screen packing based on the Kołodziej one-phase model
In the new porous media model, there is a key parameter, h, which is the angle of the flow direction to the axis of the bed and it combines the tortuosity factor s to take into account the extended flow length

Summary

Introduction

This system comprises of a rotating packed bed, static chamber, gas inlet tube situated on the top of the static chamber, a gas outlet tube connected to the central inner part of the rotating packed bed, a liquid jet splashing or spraying liquid from the central inner part of the rotating packed bed, and a liquid outlet tube located at the bottom of the static chamber.

Objectives

Results

Conclusion