In this research, the volume of fluid (VOF) method is used to study the hydrodynamics of rotating packed beds (RPBs). The model is validated, and grid independence analyses are performed for cases with different operating conditions. The droplet size distribution is investigated to characterize the hydrodynamics of RPBs. Droplet size distributions are compared in two-dimensional and three-dimensional simulations, and it is demonstrated that two-dimensional simulations can provide an accurate prediction while significantly reducing the significant computational cost. Radial distributions of droplet diameter in the packing region are studied, and different trends are observed at different rotational speeds (fluctuating at ω = 250 rpm, increasing–constant at ω = 500 rpm, and decreasing at higher rotational speeds). These trends are explained using the breakup and coalescence of droplets during droplet–packing and droplet–droplet collisions. Breakup, coalescence, and deposition regimes of droplets depend on the Weber, Ohnesorge, and impact parameters. We observed that with increasing rotational speed, the average droplet diameter and its standard deviation decreased, while changing the liquid flow rate did not significantly affect the average droplet diameter. It is also observed that there is a critical rotational speed (depending on the bed configuration), beyond which the average droplet size does not decrease with increasing rotational speed.

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A rotating packed bed (RPB) is a novel process intensification technology that increases mass transfer rate using a strong centrifugal acceleration. Inside an RPB, the inlet jet of the liquid absorbent is broken into tiny droplets. It is reported that RPBs provide 11 times larger mass transfer area compared to equal-sized packed beds and two to three orders of magnitude higher mass transfer compared to equal-sized stirred tanks. The novelty of the technology and lack of research, however, undermines the adoption of RPBs where a low mass transfer rate is the main bottleneck. In this work, we study the effect of bed size on the average droplet diameter in RPBs and investigate scale-up criteria to preserve the average droplet diameter at a large scale. Furthermore, we develop a correlation for the average droplet diameter using the experimental data and simulation results obtained using a volume of fluid (VOF) method. This correlation is obtained from dimensional analysis. The effects of rotating speed, absorbent flow rate, wire mesh packing diameter, bed diameter, absorbent viscosity, density, and surface tension are included in the dataset. Among these parameters, rotating speed, centrifugal force, and surface tension have the highest correlation coefficients (R 2 = 0.88, 0.83, and 0.42, respectively) with the average droplet diameter.carbon capture, process intensification, rotating packed bed, volume of fluid | INTRODUCTIONAccording to the Intergovernmental Panel on Climate Change (IPCC), the average global temperature will increase by 1.1-2 C before 2050, due to emissions of greenhouse gasses. [1,2] Carbon dioxide (CO 2 ) is the main contributor (≈60%) to global warming. [3] The IPCC states that the global CO 2 emissions should be decreased by 50% before 2050. [2] This is against the trends of CO 2 emissions

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