The start of ebullition in quiescent, yield-stress fluids

David J. Sherwood, Avelino E Saez

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Non-Newtonian rheology is typical for the high-level radioactive waste (HLW) slurries to be processed in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Hydrogen and other flammable gases are generated in the aqueous phase by radiolytic and chemical reactions. HLW slurries have a capacity for retaining gas characterized by the shear strength holding the bubbles still. The sizes and degassing characteristics of flammable gas bubbles in the HLW slurries, expected to be processed by the WTP are important considerations for designing equipment and operating procedures. Slurries become susceptible to degassing as the bubble concentration increases over a maximum value that depends on shear strength. This susceptibility and the process of ebullitive bubble enlargement are described here. When disturbed, the fluid undergoes localized flow around neighboring bubbles which are dragged together and coalesce, producing an enlarged bubble. For the conditions considered in this work, bubble size increase is enough to displace the weight required to overcome the fluid shear strength and yield the surroundings. The buoyant bubble ascends and accumulates others within a zone of influence, enlarging by a few orders of magnitude. This process describes how the first bubbles appear on the surface of a 7 Pa shear strength fluid a few seconds after being jarred.

Original languageEnglish (US)
Pages (from-to)101-108
Number of pages8
JournalNuclear Engineering and Design
Volume270
DOIs
StatePublished - Apr 15 2014

Fingerprint

Slurries
Radioactive Waste
Shear strength
boiling
Yield stress
bubble
bubbles
Radioactive wastes
Fluids
Waste treatment
fluid
Gases
fluids
Degassing
slurries
shear strength
radioactive wastes
flammable gases
waste treatment
radioactive waste

ASJC Scopus subject areas

  • Nuclear Energy and Engineering
  • Mechanical Engineering
  • Safety, Risk, Reliability and Quality
  • Materials Science(all)
  • Nuclear and High Energy Physics
  • Waste Management and Disposal

Cite this

The start of ebullition in quiescent, yield-stress fluids. / Sherwood, David J.; Saez, Avelino E.

In: Nuclear Engineering and Design, Vol. 270, 15.04.2014, p. 101-108.

Research output: Contribution to journalArticle

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