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Zhan, Y.*; Oya, Naoki*; Enoki, Koji*; Okawa, Tomio*; Aoyagi, Mitsuhiro; Takata, Takashi
Experimental Thermal and Fluid Science, 98, p.86 - 94, 2018/11
Times Cited Count:11 Percentile:65.34(Thermodynamics)Zhan, Y.*; Oya, Naoki*; Enoki, Koji*; Okawa, Tomio*; Ohno, Shuji; Aoyagi, Mitsuhiro; Takata, Takashi
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 6 Pages, 2017/07
It is important to set the amount of sodium droplet mechanistically for appropriate numerical evaluations of sodium leak and fire behavior in a sodium-cooled fast reactor plant. In the present work, fundamental experiments are performed to measure the splash ratio during the vertical water jet impact onto a horizontal wall. It is shown that the splash ratio can be correlated well as a function of the impact Weber number and dimensionless impact frequency.
Yi, Z.*; Oya, Naoki*; Enoki, Koji*; Okawa, Tomio*; Ohno, Shuji; Aoyagi, Mitsuhiro; Takata, Takashi
Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 7 Pages, 2016/11
It is important to set the amount of sodium droplet mechanistically for appropriate numerical evaluations of sodium leak and fire behavior in a sodium-cooled fast reactor plant. In the present work, fundamental experiments were performed to measure the splash ratio during the vertical water jet impact onto a horizontal wall. It was shown that the splash ratio can be correlated well as a function of the impact Weber number, the Strouhal number and the Ohnesorge number of the droplets impinging the liquid film.
Yi, Z.*; Oya, Naoki*; Enoki, Koji*; Okawa, Tomio*; Ohno, Shuji; Aoyagi, Mitsuhiro
Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 7 Pages, 2016/06
It is important to set the amount of sodium droplet mechanistically for appropriate numerical evaluations of sodium leak and fire behavior in a sodium-cooled fast reactor plant. In the present work, fundamental experiments were performed to measure the splash ratio during the vertical water jet impact onto a horizontal wall. It was shown that the splash ratio can be correlated well as a function of the impact Weber number and the Strouhal number of the droplets impinging the liquid film.
Oya, Naoki*; Okawa, Tomio*; Ohno, Shuji; Aoyagi, Mitsuhiro
no journal, ,
It is important to set the diameter of leakage sodium droplet mechanistically for appropriate numerical evaluations of sodium leak and fire behavior in a sodium-cooled fast reactor plant. We performed a fundamental experiment with water in order to clarify mechanism of droplet generation in this study. Impinging water jet on a flat plate was tested for various cases of jet velocity, nozzle diameter and nozzle height. The impinging behavior was visualized by means of a high-speed video camera. We measured the amount of generated droplet and the maximum droplet diameter. Observed jet flow was categorized into following three modes: drop mode which is droplet state flow, jet mode which is straight flow and lump mode which is partially constricted flow. Both the amount of generated droplet and the maximum droplet diameter increased in the following order: jet, drop and lump modes.
Oya, Naoki*; Okawa, Tomio*; Enoki, Koji*; Ohno, Shuji; Aoyagi, Mitsuhiro
no journal, ,
It is important to set the diameter of leakage sodium droplet mechanistically for appropriate numerical evaluations of sodium leak and fire behavior in a sodium-cooled fast reactor plant. We performed a fundamental experiment with water in order to clarify mechanism of droplet generation in this study. Impinging water jet on a flat plate was tested for various cases of jet velocity, nozzle diameter and nozzle height. The impinging behavior was visualized by using a high-speed video camera. We measured the amount of generated droplet and the maximum droplet diameter. Observed jet flow was categorized into following three modes: drop mode which is droplet state flow, jet mode which is straight flow and lump mode which is partially constricted flow. The amount of generated droplet had a strong correlation with the impact frequency. Larger droplet diameter was observed for the drop and lump modes.
Okawa, Tomio*; Oya, Naoki*; Yi, Z.*; Enoki, Koji*; Ohno, Shuji; Aoyagi, Mitsuhiro
no journal, ,
It is important to set the amount of sodium droplet mechanistically for appropriate numerical evaluations of sodium leak and fire behavior in a sodium-cooled fast reactor plant. In the present work, fundamental experiments were performed to measure the rate of splashing during the vertical water jet impact onto a horizontal wall. It was found that the splashing rate is negligibly small when the water jet is continuous at the impact point. Whilst, the splashing rate increased rapidly with an increase in the jet velocity when the jet was broken into droplets at the impact point. Therefore, when the fall height is longer than the breakup length, it was suggested that the dimensionless splashing rate scaled by the liquid jet flow rate can be expressed as a function of the modified Weber number of the primary droplets impacting the target. A semi-empirical method to estimate the splashing rate during liquid jet impact onto a horizontal wall was proposed based on linear stability theory.
Oya, Naoki*; Okawa, Tomio*; Enoki, Koji*; Ohno, Shuji; Aoyagi, Mitsuhiro
no journal, ,
This study aimed at improvement of sodium fire analysis method for coolant leakage in sodium-cooled fast reactor. A semi-empirical method to estimate the splashing rate during liquid jet impact onto a horizontal wall was proposed based on consideration of splashing mechanism.
Oya, Naoki*; Zhan, Y.*; Okawa, Tomio*; Enoki, Koji*; Aoyagi, Mitsuhiro; Ohno, Shuji; Takata, Takashi
no journal, ,
This study aims improvement of safety analysis for sodium fire accidents in sodium-cooled fast reactors. In the experiment, droplets were generated by collision of downward liquid jet onto a horizontal solid surface. We studied the mechanism of droplet generation and the empirical correlation of droplet amount.
Zhan, Y.*; Oya, Naoki*; Enoki, Koji*; Okawa, Tomio*; Aoyagi, Mitsuhiro; Ohno, Shuji; Takata, Takashi
no journal, ,
This study aims improvement of safety analysis for sodium fire accidents in sodium-cooled fast reactors. In the experiment, droplets were generated by collision of downward liquid jet onto a horizontal solid surface. We studied the mechanism of droplet generation and the empirical correlation of droplet amount.
Zhan, Y.*; Oya, Naoki*; Enoki, Koji*; Okawa, Tomio*; Aoyagi, Mitsuhiro; Ohno, Shuji; Takata, Takashi
no journal, ,
This study aims improvement of safety analysis for sodium fire accidents in sodium-cooled fast reactors. In the experiment, droplets were generated by collision of downward liquid jet onto a horizontal solid surface. We studied the mechanism of droplet generation and the empirical correlation of droplet amount.
Zhan, Y.*; Oya, Naoki*; Enoki, Koji*; Okawa, Tomio*; Aoyagi, Mitsuhiro; Ohno, Shuji; Takata, Takashi
no journal, ,
This study aims improvement of safety analysis for sodium fire accidents in sodium-cooled fast reactors. In the experiment, droplets were generated by collision of breakup liquid jet onto a solid surface. We studied the mechanism of droplet generation and the empirical correlation of droplet amount.