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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/12259

Title: Effect of scale-up on average shear rates for aerated non-newtonian liquids in external loop airlift reactors
Authors: Al-Masry, W.
Keywords: Airlift reactor; Bulk shear rate; Newtonian; Non-Newtonian; Wall shear rate
Issue Date: 1999
Publisher: John Wiley & Sons Inc
Citation: Biotechnology and Bioengineering: Volume 62, Issue 4, 5 Pages 494-498
Abstract: Average shear rates have been estimated experimentally in a 700-dm3 external loop airlift reactor. Aqueous pseudoplastic carboxymethylcellulose and xanthan gum solutions were used to simulate non-Newtonian behavior of biological media. Average shear rates of non-Newtonian solutions were found by analogy with Newtonian glycerol solutions using downcomer liquid velocity as the measurable parameter. Due to the complexity of local shear rate measurement, an average shear rate was assumed to exist and is proportional to superficial gas velocity. The data from this work and those in the literature were used in producing a new correlation for estimating average shear rates as a function of superficial gas velocity, geometry, and dispersion height. Wall shear rates were found to be significant. The ratio of wall shear rates to bulk shear rates were varied from 5% to 40%. Furthermore, it has been found that shear rates generated in airlift loop reactors are lower than those generated in bubble columns.
URI: http://hdl.handle.net/123456789/12259
ISSN: 00063592
Appears in Collections:College of Engineering

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