Effect of twisted tape on liquid film flow rate in rod bundle

Miyuki Akiba*, Shinichi Morooka, Kenetsu Shirakawa

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)


For a boiling water reactor (BWR), high critical-power fuel assemblies are needed to increase the thermal safety margin of the reactor core. There are seven spacers supporting the fuel rods in a BWR fuel assembly, and it is well known that the critical power is affected by the spacer geometry. Studies of spacer geometry are therefore important to the development of high critical-power fuel assemblies. Recently, Morooka et al. reported that a twisted tape increased the critical power. Figure 4 shows the improved spacer which has twisted tapes. The purpose of this study was to clarify the mechanism by which the twisted tape improves critical power by measuring the film flow rate on the fuel rod under air-water conditions. The test data shows that the twisted tape increases the film flow rate in the annular dispersed flow regime. It is thought likely that a swirling flow is generated downstream of the twisted tape and that droplet deposition is promoted by the swirl. We believe this is why the twisted tape increases critical power.

Original languageEnglish
Title of host publicationProceedings of the ASME Fluids Engineering Division Summer Meeting
EditorsT.J. O Hern, T.J. O Hern
Number of pages5
Publication statusPublished - 2003
Externally publishedYes
Event2001 ASME Fluids Engineering Division Summer Meeting - New Orleans, LA
Duration: 2001 May 292001 Jun 1


Other2001 ASME Fluids Engineering Division Summer Meeting
CityNew Orleans, LA

ASJC Scopus subject areas

  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


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