Evaluation of structural effect of BWR spacers on droplet flow dynamics

Riichiro Okawa*, Masahiro Furuya, Takahiro Arai, Tsugumasa Iiyama

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We have established an experimental system to visualize a droplet flow in a simulated BWR fuel sub-channel optically and measure the diameter and velocity of droplet after passing through a spacer. For representative spacers of ferrule and grid type, an effect of them on downstream droplets was evaluated with the experimental system. When a ferrule type spacer was simulated and implemented in both the center and side sub-channel, the vertical velocity of droplets got faster especially in the range of small diameter compared to the case of no spacer. When a grid type spacer was simulated and implemented in the center sub-channel especially, a large dispersion of vertical velocity of droplets occurred especially in the range of small diameter compared to the case of no spacer. By a computational fluid dynamics analysis for gas phase flow to drive the droplets in the sub-channel, it was confirmed qualitatively that the characteristics of droplet behavior observed in this experiment were dependent on the structure and geometry of spacer and sub-channel. Furthermore, it was revealed that a relation between a droplet diameter and velocity can be organized with a non-dimensional function derived from a momentum equation of particle in driving fluid and its drag coefficient has linear correlation with a gas Froude number.

Original languageEnglish
Article number111155
JournalNuclear Engineering and Design
Volume377
DOIs
Publication statusPublished - 2021 Jun
Externally publishedYes

Keywords

  • BWR fuel sub-channel
  • Droplet
  • Particle Tracking Velocimetry (PTV)
  • Shadow imaging
  • Spacer

ASJC Scopus subject areas

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

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