OpenFOAM Computational Fluid Dynamic Simulations of Two-Phase Flow and Mass Transfer in an Advanced-Flow Reactor

Abstract

Advanced-flow reactor (AFR) technology is an alternative to scale-up continuous flow chemistries from micro to milli scales, while retaining mass and heat transfer performance. Here we conduct two-phase computational fluid dynamic (CFD) simulations using the open source software OpenFOAM in order to predict hydrodynamic parameters in the AFR for different operating conditions. After modification and validation of the interFoam solver based on the volume-of-fluid method to account for mass transfer across immiscible interfaces, it is applied to the AFR to predict specific interfacial areas (a) and individual mass transfer coefficients (k L ) to yield overall mass transfer coefficients (k L a). The results are in good agreement with semiempirical values and the surface renewal theory of Danckwerts, except at the largest flow rates for which numerical coalescence is observed. A study of the influence of fluid properties yields the following conclusions. The contact angle is the variable that affects the flow patterns the most (and more specifically, the interfacial area); varying the contact angle can change the flow regime from bubbly to stratified flow. Decreasing surface tension decreases droplet size, but in order to achieve large specific interfacial areas and have a positive impact on the mass transfer process, a larger dispersed phase flow rate with increased holdup is also required. Viscosity of the continuous phase does not have a significant effect on mass transfer. The effect of reactor design was also seen to not be significant for the AFR designs and flow rates tested, with overall mass transfer coefficients varying within 17%.

Validated numerical fluid simulation of a thin‐layer cascade photobioreactor in OpenFOAM

“…All simulations were run in OpenFOAM 2.3.x (The OpenFOAM Foundation Ltd., London, UK ) using the Eulerian solver interFoam for a two phase system with the fluids water and air at 20°C. For validation simulations with passive species transport, adaptations were made to the solver according to resulting in the interSpeciesFoam solver (see supporting information).…”

Using computational fluid dynamics to describe H2S mass transfer across the water–air interface in sewers

“…But as mentioned above, the VOF method offers different advantages to describe the systems considered in this thesis. Therefore, mass transfer will be considered using the one-fluid approach for the VOF method as defined by Haroun et al (2010a,b) as it has been implemented by Nieves-Remacha et al (2015) and Severin (2017). The approach is based on the interFoam solver and considers one additional transport equation for both phases as outlined in Equations 1.15 and 1.16.…”

Numerical investigation on CO2 absorbed in aqueous N‐methyldiethanolamine + piperazine

“…However, these studies are mainly focused on the simple reaction, and few researches have been conducted for a reversible reaction considering the hydrodynamic parameters at the same time. With the development of computational fluid dynamics (CFD) theory and computer technology, it is possible to model flow behavior in the complex structure, and the method is potential to be extended to model mass transfer in the phase layer with finite thickness . Recently, the CFD technology has been used to model the mass transfer with first‐order reaction .…”

“…With the development of computational fluid dynamics (CFD) theory and computer technology, it is possible to model flow behavior in the complex structure, and the method is potential to be extended to model mass transfer in the phase layer with finite thickness. [25][26][27] Recently, the CFD technology has been used to model the mass transfer with first-order reaction. 28 Unfortunately, mass transfer with multiple reactions, especially for instance with reversible reaction, seems more difficult to implement in the CFD software and is modeled by introducing an enhancement factor which is the ratio of absorption rate with and without chemical reaction.…”