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dc.contributor.authorOrmonde, Christopher E.
dc.date.accessioned2010-11-29T16:57:36Z
dc.date.available2010-11-29T16:57:36Z
dc.date.issued2009
dc.identifier.urihttp://hdl.handle.net/2144/1382
dc.description.abstractIn the Spallation Neutron Source (SNS) facility at Oak Ridge National Laboratory (ORNL), the deposition of a high-energy proton beam into the liquid mercury target forms bubbles whose asymmetric collapse cause Cavitation Damage Erosion (CDE) to the container walls, thereby reducing its usable lifetime. One proposed solution for mitigation of this damage is to inject a population of microbubbles into the mercury, yielding a compliant and attenuative medium that will reduce the resulting cavitation damage. This potential solution presents the task of creating a diagnostic tool to monitor bubble population in the mercury flow in order to correlate void fraction and damage. Details of an acoustic waveguide for the eventual measurement of two-phase mercury-helium flow void fraction are discussed. The assembly’s waveguide is a vertically oriented stainless steel cylinder with 5.08cm ID, 1.27cm wall thickness and 40cm length. For water experiments, a 2.54cm thick stainless steel plate at the bottom supports the fluid, provides an acoustically rigid boundary condition, and is the mounting point for a hydrophone. A port near the bottom is the inlet for the fluid of interest. A spillover reservoir welded to the upper portion of the main tube allows for a flow-through design, yielding a pressure release top boundary condition for the waveguide. A cover on the reservoir supports an electrodynamic shaker that is driven by linear frequency sweeps to excite the tube. The hydrophone captures the frequency response of the waveguide. The sound speed of the flowing medium is calculated, assuming a linear dependence of axial mode number on modal frequency (plane wave). Assuming that the medium has an effective-mixture sound speed, and that it contains bubbles which are much smaller than the resonance radii at the highest frequency of interest (Wood’s limit), the void fraction of the flow is calculated. Results for water and bubbly water of varying void fraction are presented, and serve to demonstrate the accuracy and precision of the apparatus.en_US
dc.description.sponsorshipSupported by the ORNL Spallation Neutron Source, which is managed by UT- Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.en_US
dc.language.isoen_USen_US
dc.publisherBoston Universityen_US
dc.rightsAttribution 3.0 Unported*
dc.rights.urihttp://creativecommons.org/licenses/by/3.0/*
dc.subjectAcousticsen_US
dc.subjectBubbly liquidsen_US
dc.subjectSound speeden_US
dc.subjectAcoustic resonatoren_US
dc.subjectVoid fractionen_US
dc.titleA FLOW-THROUGH ACOUSTIC WAVEGUIDE FOR TWO-PHASE BUBBLY FLOW VOID FRACTION MEASUREMENTen_US
dc.typeThesisen_US


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Attribution 3.0 Unported
Except where otherwise noted, this item's license is described as Attribution 3.0 Unported