Modeling and simulation of gas vortex flow dynamics to understand the nature of mass transfer enhancement

Abstract

Vortex flow has been demonstrated to be an effective way of process intensification for interphase mass transfer. However, the underlying principles of this phenomenon are not yet fully known. To understand the nature of gas vortex flow in improving process intensification from a fluid flow perspective, this work conducts an experimental investigation and numerical simulations to compare the differences in energy loss, static pressure, main velocity, and turbulent kinetic energy between the vortex and the axial gas flow inside a countercurrent contactor operated at a flow rate of 50–250 L/min. The results indicate that the energy loss increases with increasing gas flow rate, while the Euler number remains stable at 2.49 ± 0.17, which is 21.05% higher than the conventional axial flow. The vortex flow displays higher values and gradients in the distribution of static pressure, tangential, axial velocity, and turbulent kinetic energy, which is directly linked to the enhanced interphase contact, mixing, and mass transfer processes. Additionally, the tangential velocity of vortex flow exhibits a decaying behavior, but it also has an extra tangential dimension, which was a critical factor for process enhancement compared to conventional axial flow. Moreover, semi-empirical models are developed to characterize the parameters of the maximum tangential velocity and its radial position for the vortex flow with R2 = 0.892 and 0.919, respectively. The results may provide a positive reference for the design, optimization, and operation of countercurrent vortex contactors.