Measurements of Gas Bubble Size Distributions in Flowing Liquid Mercury
- ORNL
ABSTRACT Pressure waves created in liquid mercury pulsed spallation targets have been shown to induce cavitation damage on the target container. One way to mitigate such damage would be to absorb the pressure pulse energy into a dispersed population of small bubbles, however, measuring such a population in mercury is difficult since it is opaque and the mercury is involved in a turbulent flow. Ultrasonic measurements have been attempted on these types of flows, but the flow noise can interfere with the measurement, and the results are unverifiable and often unrealistic. Recently, a flow loop was built and operated at Oak Ridge National Labarotory to assess the capability of various bubbler designs to deliver an adequate population of bubbles to mitigate cavitation damage. The invented diagnostic technique involves flowing the mercury with entrained gas bubbles in a steady state through a horizontal piping section with a glass-window observation port located on the top. The mercury flow is then suddenly stopped and the bubbles are allowed to settle on the glass due to buoyancy. Using a bright-field illumination and a high-speed camera, the arriving bubbles are detected and counted, and then the images can be processed to determine the bubble populations. After using this technique to collect data on each bubbler, bubble size distributions were built for the purpose of quantifying bubbler performance, allowing the selection of the best bubbler options. This paper presents the novel procedure, photographic technique, sample visual results and some example bubble size distributions. The best bubbler options were subsequently used in proton beam irradiation tests performed at the Los Alamos National Laboratory. The cavitation damage results from the irradiated test plates in contact with the mercury are available for correlation with the bubble populations. The most effective mitigating population can now be designed into prototypical geometries for implementation into an actual SNS target.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1050331
- Resource Relation:
- Conference: ASME 2012 Fluids Engineering Division Summer Meeting, Rio Grande, PR, USA, 20120708, 20120712
- Country of Publication:
- United States
- Language:
- English
Similar Records
Small Gas Bubble Experiment for Mitigation of Cavitation Damage and Pressure Waves in Short-pulse Mercury Spallation Targets
Creating Small Gas Bubbles in Flowing Mercury Using Turbulence at an Orifice
Related Subjects
BUBBLES
CAVITATION
DIAGNOSTIC TECHNIQUES
GLASS
ILLUMINANCE
IMPLEMENTATION
IRRADIATION
LANL
MERCURY
PERFORMANCE
PLATES
PROTON BEAMS
SPALLATION
TARGETS
TURBULENT FLOW
ULTRASONIC WAVES
mercury diagnostic bubbles measurement population MBTL