On the Volume of Fluid Simulation Details and Droplet Size Distribution inside Rotating Packed Beds

Abstract

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.