Laser Doppler Velocimetry Analysis of Gas Flow Impact on Droplet Movement in a Rotating Packed Bed

article in a collection out of WoS and Scopus

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The surface of droplets in the outer cavity zone creates considerable interfacial area in the entire rotating packed bed (RPB) unit. Many studies focus solely on the dynamics of the liquid, especially the size, spatial distribution, or velocity of the droplets. However, to accurately predict the movement and the residence time of the droplet, the forced gas flow needs to be studied. It may influence forces acting on the droplet and, therefore, affect the droplet hydrodynamics. In this study, Laser Doppler Velocimetry is deployed to analyse the gas velocity profiles in a unique transparent RPB. A metal foam with porosity of 92%, inner diameter of 150 mm, and outer diameter of 300 mm was used as the packed bed, and it operated at regimes ranging from 400 to 1200 rpm. Liquid flow rate was 90 kg/h, and gas flow rates ranged from 20 to 60 m3/h. Results show that the liquid droplets in the cavity zone are not only influenced by the packing speed, as it is the main source of its kinetic energy. Their velocity decreases also with the higher gas flow rate and with the distance from the packing. A correlation for the liquid velocity in the cavity zone is proposed based on the experimental results.

The surface of droplets in the outer cavity zone creates considerable interfacial area in the entire rotating packed bed (RPB) unit. Many studies focus solely on the dynamics of the liquid, especially the size, spatial distribution, or velocity of the droplets. However, to accurately predict the movement and the residence time of the droplet, the forced gas flow needs to be studied. It may influence forces acting on the droplet and, therefore, affect the droplet hydrodynamics. In this study, Laser Doppler Velocimetry is deployed to analyse the gas velocity profiles in a unique transparent RPB. A metal foam with porosity of 92%, inner diameter of 150 mm, and outer diameter of 300 mm was used as the packed bed, and it operated at regimes ranging from 400 to 1200 rpm. Liquid flow rate was 90 kg/h, and gas flow rates ranged from 20 to 60 m3/h. Results show that the liquid droplets in the cavity zone are not only influenced by the packing speed, as it is the main source of its kinetic energy. Their velocity decreases also with the higher gas flow rate and with the distance from the packing. A correlation for the liquid velocity in the cavity zone is proposed based on the experimental results.

LDV, gas flow, liquid flow, rotating packed bed, velocity profiles

23.06.2024

ICLASS

Shanghai

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