Analytical Model of Droplet Motion in Rotating Packed Bed

article in a collection out of WoS and Scopus

English

A rotating packed bed is a device used to intensify processes such as absorption or distillation. In this device, liquid is sprayed onto the inner surface of a rotating porous annulus. The liquid flows through the packed bed due to cen-trifugal force, forming a large interfacial area. Once the liquid reaches the packing’s outer surface, ligaments emerge from pores and break up into droplets. These droplets then move freely through the outer cavity with their motion influenced mainly by the surrounding gas flow and its drag force. All these droplets contribute to mass transfer in the cavity zone, therefore, their hydrodynamic characteristics, such as residence time, trajectory length and impact velocity, need to be studied. In this work, an analytical hydrodynamic model based on Newton’s second law and kinematic equations is developed and validated using phase Doppler velocimetry measurements. As droplets slow down due to drag force, the smallest droplets (<100 μm) lose their momentum quickly causing them to follow the gas flow and impinge on the casing with tangential velocity suggesting a low probability of splashing. These droplets have longer trajectories and residence times. Contrary, large droplets (>100 μm) retain their momentum longer and impact the casing with higher radial velocity which may indicate splashing conditions. Their trajectories and resi-dence times are short.

Hydrodynamics; Rotating packed bed

HÁJEK, O.; MALÝ, M.; BLATKIEWICZ, M.; MAJDZIK, M.; JASKULSKI, M.; CEJPEK, O.; JÍCHA, M.

21. 5. 2025

ILASS Americas

Bozeman, Montana

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https://ilass.org/papers2025.php