Error in bubble velocity measurement using 4-sensor void probe due to interface deformation

Satou, Akira; Sagawa, Jun*; Sun, Haomin; Shibamoto, Yasuteru; Yonomoto, Taisuke

Nuclear Engineering and Design, 379, p.111234_1 - 111234_7, 2021/08

https://doi.org/10.1016/j.nucengdes.2021.111234

Multi-sensor void probe is efficient to measure the local parameters of two-phase flow such as bubble interface velocity. In general, meniscus due to surface tension is formed and shape of the gas-liquid interface deforms when an object contacts the gas-liquid interface. The deformation of the interface by penetration of the front sensor affects the penetration time of the rear sensor, and as a result, an error can occur in the measurement of the bubble interface velocity. The characteristics of the meniscus formation around the sensor was investigated and the error in the measurement of the interface velocity was evaluated. It was clarified that the size, shape of the sensor and the contact angle of the sensor surface affect the error in interface velocity measurement as well as the interface velocity itself, and no measurement error would occur in air-to-water penetration by using a sensor with a large surface contact angle. A 4-sensor void probe was applied to bubbly flow to measure the bubble interface velocity. The measurement error due to the meniscus also occurred in the actual experimental measurement. It was shown that it is necessary to use only the velocity of the lower surface of the bubble or to make certain appropriate error correction for the velocity of the upper interface of the bubble.

Numerical study on an interface compression method for the volume of fluid approach

Okagaki, Yuria; Yonomoto, Taisuke; Ishigaki, Masahiro; Hirose, Yoshiyasu

Fluids (Internet), 6(2), p.80_1 - 80_17, 2021/02

https://doi.org/10.3390/fluids6020080

Density stratification breakup by a vertical jet; Experimental and numerical investigation on the effect of dynamic change of turbulent Schmidt number

Abe, Satoshi; Studer, E.*; Ishigaki, Masahiro; Shibamoto, Yasuteru; Yonomoto, Taisuke

Nuclear Engineering and Design, 368, p.110785_1 - 110785_14, 2020/11

https://doi.org/10.1016/j.nucengdes.2020.110785

Unsteady natural convection in a cylindrical containment vessel (CIGMA) with external wall cooling; Numerical CFD simulation

Hamdani, A.; Abe, Satoshi; Ishigaki, Masahiro; Shibamoto, Yasuteru; Yonomoto, Taisuke

Energies (Internet), 13(14), p.3652_1 - 3652_22, 2020/07

https://doi.org/10.3390/en13143652

Study on dryout and rewetting during accidents including ATWS for the BWR at JAEA

Satou, Akira; Wada, Yuki; Shibamoto, Yasuteru; Yonomoto, Taisuke

Nuclear Engineering and Design, 354, p.110164_1 - 110164_10, 2019/12

https://doi.org/10.1016/j.nucengdes.2019.110164

JAEA has conducted a series of experimental researches on the Post-boiling transition heat transfer, transient critical heat flux and rewetting for BWRs. Experimental data bases covering the anticipated operational conditions was developed; the significance of the precursor cooling was identified. This paper presents approaches of the present research focusing on the anticipated transient without scram, effects of the spacer and physical understanding of the phenomena for development of mechanistic model together with promising results obtained so far.

CFD analysis of the CIGMA experiments on the heated JET injection into containment vessel with external surface cooling

Hamdani, A.; Abe, Satoshi; Ishigaki, Masahiro; Shibamoto, Yasuteru; Yonomoto, Taisuke

Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.5463 - 5479, 2019/08

Experimental investigation of decontamination factor dependence on aerosol concentration in pool scrubbing

Sun, Haomin; Shibamoto, Yasuteru; Okagaki, Yuria; Yonomoto, Taisuke

Science and Technology of Nuclear Installations, 2019, p.1743982_1 - 1743982_15, 2019/06

https://doi.org/10.1155/2019/1743982

Influence of grating type obstacle on stratification breakup by a vertical jet

Abe, Satoshi; Ishigaki, Masahiro; Shibamoto, Yasuteru; Yonomoto, Taisuke

Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 9 Pages, 2018/10

Experimental investigation on dependence of decontamination factor on aerosol number concentration in pool scrubbing under normal temperature and pressure

Sun, Haomin; Machida, Shinichi*; Shibamoto, Yasuteru; Okagaki, Yuria; Yonomoto, Taisuke

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 7 Pages, 2018/07

Experimental investigation of Post-BT heat transfer and rewetting phenomena

Satou, Akira; Wada, Yuki; Le, T. D.; Shibamoto, Yasuteru; Yonomoto, Taisuke

Proceedings of ANS International Conference on Best Estimate Plus Uncertainties Methods (BEPU 2018) (USB Flash Drive), 12 Pages, 2018/00

Experiments were performed under the condition of AOO for BWRs to obtain Post-BT heat transfer rate, deposition rates of liquid droplets, and the rewetting behavior after the core dryout. Rewetting behavior was analytically investigated and a relation among the rewetting velocity, the hot wall temperature, and the heat transfer rates in the precursory cooling and wetted regions were obtained. In addition, experiments simulating the condition of ATWS were newly performed with simulated ferrule spacers especially to investigate the spacer effect. It was found that the heat transfer rates were enhanced by the spacers, which were compared with existing prediction models for the validation. The spacers also appeared to increase the rewetting velocity slightly. Since the precursory cooling was found to play an important role on the rewetting behavior through the series of prior experiments, new experiments are conducted focusing on the precursory cooling. In those experiments, the behaviors of liquid film and droplets around the rewetting front were observed to investigate the mechanism of the precursory cooling.