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Evaluation of centrifugal pump performance derating procedures for non-Newtonian slurries

Thesis (MTech(Civil Engineering))--Cape Peninsula University of Technology, 2006. / The performance of a centrifugal pump is altered for slurry or viscous materials (Stepanoff,
1969) and this needs to be accounted for. Usually, the suitable selection and evaluation of
centrifugal pumps is based only on water pump performance curves supplied by the pump
manufacturer (Wilson, Addie, Sellgren & Clift, 1997). In 1984 Walker and Goulas
conducted a number of pump performance tests with kaolin clay slurries and coal slurries on
a Warman 4/3 AH horizontal slurry pump and a Hazleton 3-inch B CTL horizontal pump
(Walker and Goulas, 1984).
Walker and Goulas have analysed the test data and correlated the performance derating both
at the best efficiency flow rate (BEP) and at 10% of the best efficiency flow rate (0.1 BEP)
to the modified pump Reynolds number (NRep). They have noticed that the head and the
efficiency reduction ratio decreased for the pump Reynolds number less then 10⁶.

Furthermore, Walker and Goulas obtained a reasonably good agreement (± 5%) between
pump test data for non-Newtonian materials and pump performance prediction using the
Hydraulics Institute chart. Sery and Slatter (2002) have investigated pump deration for non-Newtonian yield pseudoplastic materials. The NRep was calculated using the Bingham
plastic viscosity (µp). Results have shown good agreement with regard to head and efficiency
reduction ratios in comparison with previous work. However, Sery and Slatter's pump
performance correlation using the HI chart did not reach the same conclusion. Error margin
of ± 20% and ± 10% were found for head and efficiency respectively. This study is an attempt to reconcile the differences between Walker and Goulas (1984) and
Sery and Slatter (2002) and extend the evaluation of these derating methods to pseudoplastic
materials. The test work was conducted in the Flow Process Research Centre laboratory of
the Cape Peninsula University of Technology using two centrifugal pumps; a Warman 6/4
and a GrW 4/3. The materials used were water, CMC solution bentonite and kaolin
suspension at different concentrations (7% and 9% by weight for bentonite; 5%, 6% and 7%
by weight for CMC; 17%, 19% and 21% by volume for kaolin).

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:cput/oai:localhost:20.500.11838/2170
Date January 2006
CreatorsKabamba, Batthe Matanda
ContributorsSery, G., Slatter, P. T., Cape Peninsula University of Technology. Faculty of Engineering. Dept. of Civil Engineering & Surveying.
PublisherCape Peninsula University of Technology
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Rightshttp://creativecommons.org/licenses/by-nc-sa/3.0/za/

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