Shear induced removal of calcium carbonate scale from polypropylene and copper tubes

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

This paper presents an analytical model and experimental study of adhesion and fluid shear removal of calcium carbonate scale on polypropylene and copper tubes in laminar and turbulent water flows, with a view toward understanding how scale can be controlled in solar absorbers and heat exchangers. The tubes are first coated with scale and then inserted in a flow through apparatus. Removal is measured gravimetrically for Reynolds numbers from 525 to 5550, corresponding to wall shear stresses from 0.16 to 6.0 Pa. The evolutionary structure of the scale is visualized with scanning electron microscopy. Consistent with the predictive model, calcium carbonate is more easily removed from polypropylene than copper. In a laminar flow with a wall shear stress of 0.16 Pa, 65% of the scale is removed from polypropylene while only 10% is removed from copper. Appreciable removal of scale from copper requires higher shear stresses. At Reynolds number of 5500, corresponding to a wall shear stress of 6.0 Pa, 30% of the scale is removed from the copper tubes. The results indicate scale will be more easily removed from polypropylene, and by inference other polymeric materials, than copper by flushing with water.

Original languageEnglish (US)
Title of host publicationProceedings of the ASME 3rd International Conference on Energy Sustainability 2009, ES2009
Pages727-739
Number of pages13
DOIs
StatePublished - Dec 1 2009
EventASME 3rd International Conference on Energy Sustainability, ES2009 - San Francisco, CA, United States
Duration: Jul 19 2009Jul 23 2009

Publication series

NameProceedings of the ASME 3rd International Conference on Energy Sustainability 2009, ES2009
Volume2

Other

OtherASME 3rd International Conference on Energy Sustainability, ES2009
Country/TerritoryUnited States
CitySan Francisco, CA
Period7/19/097/23/09

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