scispace - formally typeset
Search or ask a question
Author

Yoshiyasu Hirose

Bio: Yoshiyasu Hirose is an academic researcher from Japan Atomic Energy Agency. The author has contributed to research in topics: Electrical impedance tomography & Electrode. The author has co-authored 2 publications.

Papers
More filters
Journal ArticleDOI
TL;DR: Pool scrubbing is one of the promising means for mitigating radioactive aerosol release into the environment in nuclear severe accident scenarios as discussed by the authors, however, the influence of operational conditions on its percolation is unknown.
Abstract: Pool scrubbing is one of the promising means for mitigating radioactive aerosol release into the environment in nuclear severe accident scenarios. The influence of operational conditions on its per...

4 citations

Journal ArticleDOI
TL;DR: In this paper, an electrical impedance tomography (EIT) system was proposed for imaging of phase distribution in gas-water two-phase flow from boundary measurement of electrical potentials in response to direct current injection.

Cited by
More filters
Journal ArticleDOI
TL;DR: In this article , the authors investigated the hydrodynamics in two typical pool scrubbing experiments with the two-fluid model, and the influence of some key factors including bubble diameter, nozzle submergence as well as interaction models are analyzed.
Abstract: Abstract Pressure relief by blowdown is one of the most important measures to prevent excessive pressures in the primary circuit or containment in severe nuclear accidents. Pool scrubbing can significantly reduce the release of radioactive materials, e.g., aerosols, to the environment during the pressure relief. The decontamination factor indicating the particle retention efficiency depends, among other factors, on the hydrodynamic conditions of the gas-liquid two-phase flow inside the pool. In the present work, the hydrodynamics in two typical pool scrubbing experiments is investigated with the two-fluid model, and the influence of some key factors including bubble diameter, nozzle submergence as well as interaction models are analysed. One case is a rectangular pool and the other is a cylindrical column, and their injection Weber number is around 2×10 3 and 4×10 5 , respectively. The numerical results show that as the distance from the nozzle exit increases, the void fraction and velocity field expand from the central region, where the nozzle is located, to the whole cross section. The profile and its development depends largely on the bubble size and the interaction force model. It reveals that in the monodisperse simulation, the tuning of bubble diameter is necessary for achieving good agreement, although it is difficult for high velocity gas injection. More information is required to properly describe the bubble size distribution as well as its evolution in pool scrubbing conditions. Furthermore, the experimental data show clear drag reduction in the bubble swarm generated by the gas jet, and the mechanism and model improvement possibilities need to be investigated.

1 citations

Journal ArticleDOI
TL;DR: In this article , Lagrangian simulations of particles advected by steady internal circulation in a spherical bubble are used to show that particle centrifugal velocity becomes scale invariant for low-Stokes numbers (St≤10-2) when the characteristic timescale is chosen to be that for transversal particle motion at the Stokes terminal velocity corresponding to the local fluid acceleration.
Journal ArticleDOI
TL;DR: In this paper , a simplified radionuclide transport scrubbing code utilizes classical aerosol scrubbing mechanisms to model this phenomenon and predict aerosol masses reaching the cover gas region, and the experimental results were found to match the trends found in the scrubbing model closely, but significantly more scrubbing was seen experimentally.