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Development of a Numerical Design Tool
for Spallation Neutron Source Cavitation Mitigation--Dynaflow, Inc., 10621‑J Iron Bridge Rd,
Jessup, MD 20794; 301‑604‑3688;
www.dynaflow-inc.com
Dr. Georges L. Chahine,
Principal Investigator, glchahine@dynaflow-inc.com
Dr. Georges L. Chahine,
Business Official, glchahine@dynaflow-inc.com
DOE Grant No. DE‑FG02‑07ER84839
Amount:
$749,958
The generation of a strong shock wave in the Spallation Neutron
Source (SNS) can lead to cavitation and significant
erosion on the vessel wall containing the liquid mercury target. Based on preliminary numerical and
experimental work at various laboratories, it has been proposed that strategies
such as inserting a cloud of small gas bubbles or a gas layer in the mercury
target could absorb and deflect the shock waves and protect the walls from cavitation erosion.
Another strategy involves the reduction of cavitation
through new designs that take advantage of wall shaping and deformation, and
energy absorption. In order to aid the
design of such cavitation-mitigation schemes, this
project will develop an advanced numerical software package, which couples multiscale, multiphase compressible fluid solvers with
structure dynamics solvers. This code
will be capable of simulating the relevant features of the flow, namely shock
wave propagation through bubbly media, large liquid/gas interface deformations,
shock wave induced cavitation, and deformation of
structures due to shock wave and cavitation/structure
interactions. In Phase I, multiphase
codes adapted to study this problem were able to capture high pressure wave
propagation in bubbly media, along with the interaction of the wave with the
bubbles, free surface, and the wall structures.
The potential success of different cavitation
mitigation measures (including wall shape design, insertion of an air layer,
and the generation of a bubbly medium) was demonstrated. Phase II will involve further improvements to
the software package, including a generalization of interface capturing schemes
for broader multiphase/material flows, a multiscale cavitation model for bubbly media, and a structure code for
simulation of full fluid/structure interaction.
The software package will then be validated by using existing and
conducting benchmark experiments in SNS mercury test loops.
Commercial Applications and
Other Benefits as described by the awardee:
In
addition to the SNS application, the software package should have application
to multiple fields: (1) naval
applications, where the mitigation of shock wave impact is of keen interest to
vessel protection and to propeller blade design; (2) chemical processes, to
improve performance of bubble column reactors and multiphase slurries; and (3)
minimally invasive medical procedures that use acoustic cavitation-based
treatments such as shock wave lithotripsy.