The Effect of Impeller and Tank Geometry on Power Number for a Pitched Blade Turbine

Previous studies of the Rushton turbine have shown that the power number is sensitive to the details of impeller geometry, and in particular to the blade thickness, but is independent of the impeller diameter to tank diameter ratio. In this paper, a similar study is reported for the pitched blade im...

Full description

Saved in:
Bibliographic Details
Published in:Chemical engineering research & design 2002-05, Vol.80 (4), p.364-372
Main Authors: Chapple, D., Kresta, S.M., Wall, A., Afacan, A.
Format: Article
Language:English
Subjects:
Applied sciences
Chemical engineering
Exact sciences and technology
Mixing
pitched blade impeller
power
Rushton turbine
stirred tank
torque
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Previous studies of the Rushton turbine have shown that the power number is sensitive to the details of impeller geometry, and in particular to the blade thickness, but is independent of the impeller diameter to tank diameter ratio. In this paper, a similar study is reported for the pitched blade impeller. The results show that the power number is independent of blade thickness, but dependent on the impeller to tank diameter ratio. This is exactly the opposite result to that observed for the Rushton turbine. Physical explanations are given for the differences in behaviour between the two impellers. For the Rushton turbine, power consumption is dominated by form drag, so details of the blade geometry and flow separation have a significant impact (30%) on the power number. For the pitched blade impeller, form drag is not as important, but the flow at the impeller interacts strongly with the proximity of the tank walls, so changes in the position of the impeller in the tank can have a significant impact on the power number.
ISSN:0263-8762
DOI:10.1205/026387602317446407