Prediction of interfacial shear stress and pressure drop in vertical two-phase annular flow

Zhang, H.*; Umehara, Yutaro*; Yoshida, Hiroyuki; Mori, Shoji*

International Journal of Heat and Mass Transfer, 218, p.124750_1 - 124750_11, 2024/01

https://doi.org/10.1016/j.ijheatmasstransfer.2023.124750

"Learning from the past and finding new knowledge" in nuclear reactor safety research; A Roundtable discussion between veteran and young researchers

Abe, Yutaka*; Nishi, Yoshihisa*; Iwaki, Chikako*; Umehara, Yutaro*; Horiguchi, Naoki; Sonoda, Hiroki*

no journal, , 

Human resource development is an important issue in the nuclear field, and it is extremely important to transfer the know-how of veteran researchers who have accumulated over many years in the research field to the younger generation. In the field of reactor safety research in particular, the research environment has been changing in recent years, as it has become more difficult to conduct research using large experimental equipment, and many young researchers are finding the difficulty. This session will provide a forum in the form of a "round-table discussion" to discuss what veteran researchers want to tell young researchers and what young researchers want to ask veteran researchers. Through the panel discussion, communication between veteran researchers and young researchers about the future in the field will be promoted.

Development of validation technology for detailed two-phase flow simulation codes to optimize innovative reactor design, 4; Development of a measurement technique for liquid film thickness in R134a-ethanol two-phase flow simulating high-temperature and high-pressure environments

Mori, Shoji*; Zhang, H.*; Umehara, Yutaro*; Horiguchi, Naoki; Yoshida, Hiroyuki

no journal, , 

To ensure nuclear safety, understanding of liquid film behavior of annular flow like flow near fuel rods in BWRs is important. It is hard to experimentally obtain thin liquid behavior in BWRs because of technical limits under the high pressure and temperature, 7MPa and 285C, and to understand the behavior sufficiently. Therefore, in this study, liquid film behavior under the actual condition was reproduced using ethanol-HFC134a system at 0.7MPa and 40C such as a university laboratory, which has almost same physical properties with the actual water-vapor system. In addition, the liquid film behavior was measured using the constant electric current method, and the measurable range and accuracy of the method were examined.