An examination of Wen and Yu's formula for predicting the onset of fluidisation
View / Open Files
Authors
Gibson, IA
Slim, CJ
Zheng, Y
Scott, SA
Davidson, JF
Hayhurst, AN
Publication Date
2018Journal Title
Chemical Engineering Research and Design
ISSN
0263-8762
Publisher
Elsevier BV
Volume
135
Pages
103-111
Type
Article
Metadata
Show full item recordCitation
Gibson, I., Slim, C., Zheng, Y., Scott, S., Davidson, J., & Hayhurst, A. (2018). An examination of Wen and Yu's formula for predicting the onset of fluidisation. Chemical Engineering Research and Design, 135 103-111. https://doi.org/10.1016/j.cherd.2018.05.009
Abstract
© 2018 Classical methods (measuring the pressure drop across a bed for different flowrates of air through the bed) were used to determine the superficial velocity for minimum fluidisation, Umf, of sieved particles of alumina. The particles were characterised optically using an instrument (Morphologi G3, Malvern Instruments), which, from pixelated, enlarged photographs, measured the particles’ mean diameter, dp, to be 0.48 ± 0.04 mm and their sphericity, ϕ, to be 0.77 ± 0.09. Values of Umfwere measured for the temperature in the electrically heated bed varying from 14 to 920 °C. The results were analysed using Ergun's equation; one outcome was that the voidage, εmf, in an incipiently fluidised bed was found to be related to the particles’ sphericity by: (1−εmf)/ϕ2εmf3=12.2±0.4. The measured Umfwere significantly larger than the values predicted by Wen and Yu's equation, if the mean diameter of the particles was taken, as recommended, to be the geometric mean of the upper and lower sieve sizes, used when preparing the particles. Alternatively, the measured values of Umfwere over-predicted by Wen and Yu's equation, when using the optically measured mean size of the particles. The best predictions of Umfwere made by using the optically measured mean values of both dpand ϕ, together with Ergun's equation and the above equation coupling εmfand ϕ. Such a procedure is proposed for estimating Umfin general. No evidence was found for εmfvarying with temperature.
Identifiers
External DOI: https://doi.org/10.1016/j.cherd.2018.05.009
This record's URL: https://www.repository.cam.ac.uk/handle/1810/283577
Rights
Licence:
http://www.rioxx.net/licenses/all-rights-reserved
Statistics
Total file downloads (since January 2020). For more information on metrics see the
IRUS guide.
Recommended or similar items
The current recommendation prototype on the Apollo Repository will be turned off on 03 February 2023. Although the pilot has been fruitful for both parties, the service provider IKVA is focusing on horizon scanning products and so the recommender service can no longer be supported. We recognise the importance of recommender services in supporting research discovery and are evaluating offerings from other service providers. If you would like to offer feedback on this decision please contact us on: support@repository.cam.ac.uk