Full Content is available to subscribers

Subscribe/Learn More  >

Development of Prediction Technology of Two-Phase Flow Dynamics Under Earthquake Acceleration: (14) Numerical Simulation of Two-Phase Flow in Subchannels Under Accelerating Condition

[+] Author Affiliations
Hiroyuki Yoshida, Taku Nagatake, Kazuyuki Takase

Japan Atomic Energy Agency, Tokai, Ibaraki, Japan

Akiko Kaneko, Hideaki Monji, Yutaka Abe

University of Tsukuba, Tsukuba, Ibaraki, Japan

Paper No. ICONE22-30153, pp. V02AT09A014; 10 pages
  • 2014 22nd International Conference on Nuclear Engineering
  • Volume 2A: Thermal Hydraulics
  • Prague, Czech Republic, July 7–11, 2014
  • Conference Sponsors: Nuclear Engineering Division
  • ISBN: 978-0-7918-4590-5
  • Copyright © 2014 by ASME


An earthquake is one of the most serious phenomena to consider for the safety of a nuclear reactor in Japan. Therefore, structural safety of nuclear reactors has been studied and nuclear reactors were contracting with structural safety for a big earthquake. However, it is not enough for safety operation of nuclear reactors because thermal-fluid safety is not confirmed under the earthquake. For instance, behavior of gas-liquid two-phase flow is unknown in seismic conditions. Especially, fluctuation of void fraction is an important factor for the safety operation of the nuclear reactor. In previous work, fluctuation of void faction in bubbly flow was studied experimentally and theoretically to investigate the stability of the bubbly flow. In such studies, flow rate or void fraction fluctuations were given to the steady bubbly flow. In case of the earthquake, the fluctuation is not only the flow rate, but also a body force on the two-phase flow and shear force through the pipe wall. Interactions of gas and liquid through their interface also act on the behavior of the two-phase flow. The fluctuation of the void fraction is not clear for such complicated situation during the earthquake.

Therefore, the behavior of gas-liquid two-phase flow is investigated experimentally and numerically in a series of studies. In this study, to develop the predictive technology of two-phase flow dynamics under earthquake acceleration, a detailed two-phase flow simulation code with an advanced interface tracking method TPFIT (Two-Phase Flow simulation code with Interface Tracking) was expanded to two-phase flow simulation in seismic conditions. In a previous study, we performed a numerical simulation of a two-phase bubbly flow in a horizontal pipe and a vertical bubble motion in a water tank in seismic conditions. And it was confirmed that the modified TPFIT can be applicable to the bubbly flow in seismic conditions.

In this paper, the two-phase bubbly flow in a simulated single-subchannel excited by oscillation acceleration was simulated by using the expanded TPFIT. A calculation domain used in this simulation was a simplified subchannel in a BWR core. And time-series of void fraction distributions were evaluated based on predicted bubble distributions. When no oscillation acceleration was added, void fraction concentrated in a region near the wall. When oscillation acceleration was added, void fraction distribution was changed by time. And coalesces of bubbles occurred in the numerical simulation, and bubbles with relatively large diameter were observed. In the results, complicated void fraction distribution was observed, because the response of void fraction distribution on the oscillation acceleration was dependent on not only imposed acceleration, but also the bubble diameter.

Copyright © 2014 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In