Cavitation and Bubble Formation in Water Distribution Systems

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dc.contributor.authorNovak, Julia Annen
dc.contributor.committeechairEdwards, Marc A.en
dc.contributor.committeememberLoganathan, G. V.en
dc.contributor.committeememberDiplas, Panayiotisen
dc.contributor.departmentEnvironmental Engineeringen
dc.date.accessioned2014-03-14T21:35:25Zen
dc.date.adate2005-05-18en
dc.date.available2014-03-14T21:35:25Zen
dc.date.issued2005-04-08en
dc.date.rdate2008-05-18en
dc.date.sdate2005-05-03en
dc.description.abstractGaseous cavitation is examined from a practical and theoretical standpoint. Classical cavitation experiments which disregard dissolved gas are not directly relevant to natural water systems and require a redefined cavitation inception number which considers dissolved gases. In a pressurized water distribution system, classical cavitation is only expected to occur at extreme negative pressure caused by water hammer or at certain valves. Classical theory does not describe some practical phenomena including noisy pipes, necessity of air release valves, faulty instrument readings due to bubbles, and reports of premature pipe failure; inclusion of gaseous cavitation phenomena can better explain these events. Gaseous cavitation can be expected to influence corrosion in water distribution pipes. Bubbles can form within the water distribution system by a mechanism known as gaseous cavitation. A small scale apparatus was constructed to track gaseous cavitation as it could occur in buildings. Four independent measurements including visual observation of bubbles, an inline turbidimeter, an ultrasonic flow meter, and an inline total dissolved gas probe were used to track the phenomenon. All four measurements confirmed that gaseous cavitation was occurring within the experimental distribution system, even at pressures up to 40 psi. Gaseous cavitation was more likely at higher initial dissolved gas content, higher temperature, higher velocity and lower pressure. Certain changes in pH, conductivity, and surfactant concentration also tended to increase the likelihood of cavitation. For example, compared to the control at pH 5.0 and 30 psig, the turbidity increased 295% at pH 9.9. The formation of bubbles reduced the pump's operating efficiency, and in the above example, the velocity was decreased by 17% at pH 9.9 versus pH 5.0.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-05032005-171633en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05032005-171633/en
dc.identifier.urihttp://hdl.handle.net/10919/42435en
dc.publisherVirginia Techen
dc.relation.haspartThesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectGaseous Cavitationen
dc.subjectBubblesen
dc.subjectCorrosionen
dc.subjectDissolved Gasen
dc.titleCavitation and Bubble Formation in Water Distribution Systemsen
dc.typeThesisen
thesis.degree.disciplineEnvironmental Planningen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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