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Kimura, Nobuyuki; ; ; ; Kamide, Hideki; Tokuhiro, Akira; Hishida, Koichi
JNC TN9400 2000-057, 60 Pages, 2000/05
JNC-TN9400-2000-057.pdf:2.11MB
ln experimental study for the thermohydraulics of fast reactor, a simple experiment with fine measurement has been desired for understanding of phenomena and for verification of computer code rather than mockup experiments of large scale. For such purposes quality of experimental data must be improved. ln the velocity measurement, instantaneous velocity profile will have great advances for the understanding of phenomena and for the verification of computer code. ln this report two methods of the velocity profile measurement are discussed; one is ultrasound Doppler velocimetry (UDV) and the other is particle image velocimetry (PIV). These methods were applied to water experiments. The UDV was applied to pipe flow, planer jet, and the inter-wrapper flow which is seen in the gap region between subassemblies of fast reactor core. Cross check with laser Doppler velocimetly showed proper measurement of the UDV. Problems including the application to sodium experiments are also discussed. The PIV was also applied to the inter-wrapper flow. For the application to complex flow geometry, noise reduction method was developed to improve the measurement accuracy.
Kimura, Nobuyuki; Tokuhiro, Akira; Kamide, Hideki
JNC TN9400 2000-027, 181 Pages, 2000/02
JNC-TN9400-2000-027.pdf:10.28MB
A quantitative evaluation on thermal striping, in which temperature fluctuation due to convective mixing among jets causes thermal fatigue in structural components, is of importance for reactor safety. ln this study, a water experiment was performed using vertical and parallel triple jets, those are cold jet on center and hot jets on both side. The experimental parameter was discharged velocity of the triple-jet and local temperature and velocity were measured by ultrasound Doppler velocimetry and movable thermocouples. The objective is a quantification of the mixing process in the multiple-jet. Under isovelocity condition, the jets oscillated periodically and mixing among thejets was promoted by periodic oscillation. The periodic oscillation was dependent on the Strouhal number based on the discharged velocity. Under non-isovelocity condition, on the other hand, the jets did not oscillate periodically and mixing among the jets progressed more gentle compared with the case under isovelocity condition. The tempwrature fluctuation could be decomposed into coherent and random components using the phase averaging process. The rate of the coherent component in the temperature fluctuation increased and the rate of random component in temperature fluctuation decreased in proportion as the discharged velocity was increased.
Kawamura, Hideyuki; Hirose, Naoki*; Nakayama, Tomoharu*; Ito, Toshimichi
no journal, ,
We developed ocean current data measured by an Acoustic Doppler Current Profiler attached on a ferryboat across the Tsugaru Strait from October 1999 to January 2008 in this study. It is useful to understand the characteristics of the ocean current in the Tsugaru Strait for predicting oceanic dispersion of radioactive materials released from nuclear facilities around the strait and for understanding the mechanism of the Tsugaru Warm Current. The database cosists of 2,211 daily data files from October 1999 to January 2008. The data files record the components of the current speed in the east-west and north-south directions, quafifying flags and so on. The ocean current data was frequently acquired in summer compared with winter. The strong eastward ocean current corresponding to the Tsugaru Warm Current was confirmed by analyzing the ocean current data. We expect that the database will be used by many users for oceanographical study.