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Title: Void fraction, bubble size and interfacial area measurements in co-current downflow bubble column reactor with microbubble dispersion

Micro-bubbles dispersed in bubble column reactors have received great interest in recent years, due to their small size, stability, high gas-liquid interfacial area concentrations and longer residence times. The high gas-liquid interfacial area concentrations lead to high mass transfer rates compared to conventional bubble column reactors. In the present work, experiments have been performed in a down-flow bubble column reactor with micro-bubbles generated and dispersed by a novel mechanism to determine the gas-liquid interfacial area concentrations by measuring the void fraction and bubble size distributions. Gamma-ray densitometry has been employed to determine the axial and radial distributions of void fraction and a high speed camera equipped with a borescope is used to measure the axial and radial variations of bubble sizes. Also, the effects of superficial gas and liquid velocities on the two-phase flow characteristics have been investigated. Further, reconstruction techniques of the radial void fraction profiles from the gamma densitometry's chordal measurements are discussed and compared for a bubble column reactor with dispersed micro-bubbles. The results demonstrate that the new bubble generation technique offers high interfacial area concentrations (1,000 to 4,500 m 2/m 3) with sub-millimeter bubbles (500 to 900 µm) and high overall void fractions (10% – 60%)more » in comparison with previous bubble column reactor designs. The void fraction data was analyzed using slip velocity model and empirical correlation has been proposed to predict the Sauter mean bubble diameter.« less
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  1. City College of New York, NY (United States)
  2. Homi Bhabha National Inst., Mumbai (India)
Publication Date:
Grant/Contract Number:
AR0000438; NRC-27-10-1120; NRC-HQ-12-G-38-0
Accepted Manuscript
Journal Name:
Chemical Engineering Science
Additional Journal Information:
Journal Volume: 168; Journal Issue: C; Journal ID: ISSN 0009-2509
Research Org:
City College of New York, NY (United States)
Sponsoring Org:
USDOE Advanced Research Projects Agency - Energy (ARPA-E); USNRC
Contributing Orgs:
Country of Publication:
United States
09 BIOMASS FUELS; Bubble column reactor; Microbubbles; Gamma-ray densitometry; High speed video photography; Void fraction profiles
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1398057