Atomization mechanisms of a wall-impinging jet in a shallow pool

Horiguchi, Naoki; Yoshida, Hiroyuki; Kaneko, Akiko*; Abe, Yutaka*

Physics of Fluids, 35(7), p.073309_1 - 073309_17, 2023/07

https://doi.org/10.1063/5.0157032

The atomization of a liquid jet in an immiscible liquid-liquid system is significant for the safety in the nuclear industry field. The Japan Atomic Energy Agency has developed an evaluation method of a melt fuel behavior as a liquid jet in an immiscible liquid-liquid system for subsequence using mechanistic numerical simulation and has investigated liquid jet behavior in a shallow pool through numerical simulations and experiments. The paper clarifies the atomization mechanism in the wall-impinging liquid jet. Herein, the atomization behavior in the wall-impinging liquid jet in a shallow pool in an immiscible liquid-liquid system was studied in terms of droplet formation and flow field using numerical simulation and the dispersed-phase tracking method. The results show that the droplet formation in the liquid film flow of the wall-impinging liquid jet had the three patterns, and we obtained the droplet properties immediately after droplet formation and developed the theoretical criterion regions using the dimensionless numbers for droplet formation. We characterized the patterns by comparing them with the regions and elucidated the droplet formation mechanisms depending on their sources. Moreover, we elucidated that the relationship between droplet formation as the local behaviors of the jet and atomization as the whole behavior.

Droplet-entrainment phenomena affected by interfacial behavior of a high-speed gas jet into a liquid pool

Saito, Masafumi*; Kaneko, Akiko*; Abe, Yutaka*; Uchibori, Akihiro; Kurihara, Akikazu; Takata, Takashi*; Ohshima, Hiroyuki

Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 7 Pages, 2021/08

In order to provide the data for validation and improvement of the sodium-water reaction analysis code, a visualization experiment on liquid droplet entrainment in a high-pressure air jet submerged in a water pool was conducted. Diameter and velocity of entrained liquid droplets were successfully measured. The effect of a nozzle shape was elucidated.

Visualized measurement of extremely high-speed droplets in Venturi scrubber

Horiguchi, Naoki; Yoshida, Hiroyuki; Abe, Yutaka*

Journal of Nuclear Science and Technology, 56(3), p.278 - 290, 2019/03

https://doi.org/10.1080/00223131.2018.1564707

Venturi scrubber (VS) has been installed in NPPs as one of the components of filtered venting systems. It can eliminate fine aerosol particles including fission products from polluted gas. Under extremely high-velocity conditions during severe accident, the data related to the droplet in the VS, which affects decontamination performance, is insufficient. This objective is to obtain the diameter of the extremely high-speed droplets and clarify an applicability of the existing correlations for the diameter. To visualize the extremely high-velocity droplet, an optical system with high frame rate and high resolution was developed. Visualization experiment using the VS under air-water condition was conducted, and droplet diameter distributions and Sauter mean diameter (SMD) were obtained. By comparing experimental data with values evaluated by existing correlations, it was clarified that the Nukiyama-Tanasawa equation can evaluate the SMD with good accuracy in the gas velocity range 82-250 m/s.

Observation of aerosol behavior near droplet interface

Uesawa, Shinichiro; Yoshida, Hiroyuki

Konsoryu Shimpojiumu 2017 Koen Rombunshu (USB Flash Drive), 2 Pages, 2017/08

no abstracts in English

Discussion of the numerical reproduction of the Ishii-Grolmes experimental correlation

Ebihara, Kenichi; Watanabe, Tadashi

Dai-18-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Yoshishu (CD-ROM), 7 Pages, 2004/12

The Ishii-Grolmes experimental correlation, which represents the inception criteria of the droplet entrainment, has been reproduced by the lattice Boltzmann simulation[Ebihara et al., Nagare 23, 253(2004)]. It has been observed in the simulation that the droplet broke off the wave which was generated on the smooth interface of the horizontal stratified two-phase flow. The numerical and physical influence on the reproduction of the experimental correlation is discussed in this paper. It is verified that the lattice size was enough for the reproduction of the experimental correlation though the discretization of the lattice affects the simulation result numerically. It is also seen that the shape of the generated wave and the flow velocity distribution affect the simulation results as the physical influence.

Desulfurization reaction of high sulfur content flue gas treated by electron beam

Hirosawa, Shojiro*; Kojima, Takuji; Hashimoto, Shoji; Suzuki, Ryoji*; Aoki, Shinji*

Radioisotopes, 51(8), p.285 - 295, 2002/08

https://doi.org/10.3769/radioisotopes.51.285

Experiments of flue gas treatment by electron beam were carried out, using simulated lignite-burning flue gas containing SO(5500ppm), NO(390ppm) and HO(22%). Removal efficiency of SO was more than 90% at a dose of 1-2kGy. It shows applicability of electron beam for treatment of lignite-burning flue gas. Another removal reaction besides the radiation-induced radical reaction and the thermal reaction occurring without irradiation was suggested by the facts that removal of SO by the radical reaction is only a few hundreds of ppm and the removal amounts by thermal reaction under irradiation is lower than a half of total desulfurization. The mechanism similar to thermal reaction was proposed, assuming simultaneous uptake reaction of SO and NH on the surface of liquid aerosol. It was suggested that ammonium nitrate having deliquescence relative humidity(DRH) of 60% at 25 plays an important role in producing liquid aerosols. Decrease of DRH of ammonium nitrate with increasing temperature and with formation of double salt of ammonium sulfate results in enhancement of formation of liquid aerosols.

Study of uranium particle fuel fabrication with the external gelation process with the vibration dropping Method

Nishimura, Kazuhisa; Shoji, Shuichi*; *; Sato, Seiichi*; ; Endo, Hideo

JNC TN8430 2001-005, 64 Pages, 2001/09

JNC-TN8430-2001-005.pdf:4.1MB

The external gelation process is one of the candidates of MOX particle fuel fabrication for advanced recycle system. It was necessary to perform preliminary fuel fabrication with uranium before starting MOX tests. As the result of the preliminary examination, Basics conditions of the fabrication were obtained: (1)Optimized uranyl nitrate solution and PVA solution, as raw materials were prepared. (2)The frequency of vibration and the amount of flow were obtained with optimized broth (mixture) in the vibration dropping process. (3)The influence of composition of broth and concentration of ammonia solution on gelation process was obtained. (4)Impurities after aging, washing and drying spHerical gel were surveyed, (5)The spherical gel were calcined to oxide particles and the particles were characterized by TG-DTA, therefore it is certain that outlook on the sintered particles as final products is very clear. On the top of that, there were no fatal technicalities of the external gelation process through material balance and a diameter dispersion of spherical gel and oxide particles. It is necessary to perform uranium examination to solve some new problems, for instant, surface crack of spherical gel. Although almost of all the preparations are completed and fabrication examination of MOX particles with vibration dropping equipment are ready for starting.

Study of deformation of droplet in external force field by using liquid-gas model of lattice-gas

Ebihara, Kenichi; Watanabe, Tadashi

JAERI-Research 2000-042, 43 Pages, 2000/10

JAERI-Research-2000-042.pdf:2.0MB

no abstracts in English

Symmetric and asymmetric scission properties; Identical shape elongations of fissioning nuclei

Zhao, Y. L.*; Nishinaka, Ichiro; Nagame, Yuichiro; Tanikawa, Masashi*; Tsukada, Kazuaki; Ichikawa, Shinichi; Sueki, Keisuke*; Oura, Yasutsugu*; Ikezoe, Hiroshi; Mitsuoka, Shinichi; et al.

Physical Review Letters, 82(17), p.3408 - 3411, 1999/04

https://doi.org/10.1103/PhysRevLett.82.3408

no abstracts in English

None

PNC TJ1636 97-002, 73 Pages, 1997/03

PNC-TJ1636-97-002.pdf:3.62MB

no abstracts in English