An enhanced mesoscale model for laminar and turbulent three-dimensional simulations of the gas phase flow with concentration mixing in structured packing columns

Abstract

This work presents a mesoscale model (MSM) simulating the laminar and turbulent gas phase fluid dynamics and concentration mixing in structured packings, used in absorption and distillation columns or static mixers. The MSM aims to provide computationally efficient predictions of the three-dimensional distributions of pressure, velocity and concentration in the structured packing’s gas phase. The MSM is successfully calibrated and validated with virtual experiments obtained from DNS (direct numerical simulations) of a single structured packing section featuring concentration mixing under uniform and maldistributed velocity inlet profiles. The packing section scenarios exhibit a variety of physical effects, like backflow, high-velocity fronts and blockage at the packing’s borders to the wall, which are all predicted correctly by the MSM. The physical effects have an impact on concentration mixing and velocity smoothing and are particularly interesting for applications of structured packings in dividing-wall columns or static mixers. Finally, the MSM is set up to simulate cylindrical columns with alternately rotated structured packing sections, including wall regions and wipers. MSM simulations of three packed columns of varying diameter are compared against experimental data and correctly predict the pressure drop dependence on the diameter, demonstrating the MSM’s potential for scale-up predictions.