Droplet deposition and momentum transfer in annular flow

✍ Scribed by Larry B. Fore; Abraham E. Dukler

• Publisher: American Institute of Chemical Engineers
• Year: 1995
• Tongue: English
• Weight: 619 KB
• Volume: 41
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690410904

✦ Synopsis

Entrainment and deposition in gasliquid annular upflow are known to account for as much as 20% of the pressure gradient, through droplet accelerations in the core region. Momentum is transferred from the core when droplets decelerate upon impact with the liquid film. It is usually assumed that all of this momentum is transferred to the film, essentially driving the film upward in conjunction with interfacial fiction. New data, obtained for annular gas-liquid upflow in a 5.08-em-ID tube, are used in a momentum balance analysis to determine the mechanism of momentum transfer from depositing droplets. Measurements include the liquid film thickness, wall shear stress, pressure gradient, entrained liquid fraction, droplet deposition rate, droplet centerline axial velocig, and mass-average drop size for two gas-liquid systems. This analysis supports the idea that large droplets displace the film locally and decelerate primarib at the wall, effectively transfewing negligible momentum to the liquid film.