ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Local two-phase flow measurements were obtained in a pilot-scale, external-loop airlift bioreactor using hot-film anemometry and resistivity probe techniques. The radial dependence of both gas and liquid velocities and of the void fraction was substantial. Developing flow effects were pronounced, as evidenced by distinct changes in the radial profiles of fluid flow properties with axial position. For high gas flow rates, liquid acceleration effects near the sparger resulted in greatly reduced slip velocities in a substantial portion of the riser. A significant reduction in mass transfer may occur under such conditions.The point equations of continuity and motion were used to develop a differential, two-fluid model for two-phase flow in airlift risers. The only empirical parameters in the model represent frictional effects. The developing two-phase flow characteristic of airlift risers was observed to create significantly higher frictional effects at the wall than is routinely observed for fully-developed flow. Model predictions were compared to our own experimental results as well as those of Merchuk and Stein (1981). Agreement between the predicted and measured values was typically within 10% for both cases.
Additional Material:
26 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690370311
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