26aD64P
IFMIF/EVEDA事業におけるターゲット評価のための水流動装置を用いた高速流体特性評価
Evaluation of high-speed flow property by water flowing device for target study in IFMIF/EVEDA project
中庭浩一 1, 田中浩1，横峯健彦2，若井栄一1Koichi NAKANIWA1, Hiroshi TANAKA1，Takehiko YOKOMINE2 and Eiichi WAKAI1
1
日本原子力研究開発機構， 2京都大学大学院
1
Japan Atomic Energy Agency, 2 Kyoto University

2. The experimental water flowing device
2.1 Fabrications
The specification of fabricated water flowing device is shownin Table 1 and the over view of this device is shown in Fig. 1.
Fig. 2 (a) shows the simulated piping of ELTL, while Fig. 2 (b)shows the simulated piping of FMIT.
2.2 Valuation Tests
The visualized high-speed liquid flows at the flow rates of 4m/s ∼ 15 m/s under 10 kPa ∼ 100 kPa will be obtained withusing the two kinds of the ducts in order to compare theirperformances.
3. Experiments and Results
The valuation tests using this device for simulated cavitation
phenomena in the simulated piping of ELTL were performed
under a collaboration studies with Kyoto Univ. In this device, it
tested in the principal objective that reproduced vibration
supposed cavitation phenomena which occurred in ELTL. The
detection of cavitation in ELTL used AE sensor, but it used anaccelerometer as this device does not have the equipment.
Although because this device could not visualize jet
impingement point expected that cavitation would occur,
identify the outbreak of cavitation could not only with anaccelerometer, but by the technique [2] that was developed by
the nuclear reactor plumbing by the plumbing outside to detect
cavitation using an accelerometer, cavitation outbreakevaluated it using ratio of acceleration rms in the expected
point and in the upper reaches. Fig.3 shows Position ofacceleration measured. Positions are the jet impingement pointand its upstream 150 mm point. Fig.4 shows an example of theacceleration result of a measurement. Table 2 and Fig.5 show
in results of experiments. By 8 m/s, 30 kPa and 15 m/s, theatmospheric pressure that the number of cavitation isapproximately equal in, the ratio of rms becomes the about thesame value, and an inertial force is supposed when the state of
the high speed jet that a low speed jet and the jet width that
became small enlarged becomes similar.
4. Summary
The ratio of acceleration rms values which are measured at thejet impingement point and its upstream 150 mm point wasagreed with tendencies from cavitation bearing the incipient
stage to the transition area in comparison with a study of thepast. Thus, a visualized water flow test would be necessary
since it is difficult to identify the area where the cavitation
occurs merely by the experiment using the accelerometer.

Plasma Fusion Res. 88 (2012) pp. 691-705.
[2] S.Mizuyama, M.Murase,“Detection of Cavitation Behavior using
Accelerometer and Microphone outside of Piping at Orifice”, INSS
Journal,13,(2006) pp.115-127.
Table 1 Spec. of the experimental water flowing device
Testing fluid

Water

Temp.

0 ~ 25 °C

Flow rate

650 L/min (maximum)

Material

TA: Acrylic / Pipes: Stainless steel

Flow speed at outlet of nozzle

4 ~ 15 m/s

Operating pressure

10 kPa ~ 100 kPa (Atmosphere)

2.8 m

1. Introduction and BackgroundIn the IFMIF/EVEDA project, the various validation
experiments using the 1/2.6 scale down-sized duct of the Litarget in EVEDA Li Test Loop (ELTL) have been performed
until 2014 [1]. In this study, parallel to the ELTL experiments,
the experimental water flowing device was fabricated in order
to compare the flow properties obtained from two kinds of theducts which simulate the quench tank through the downstreamof Target assembly (TA). One duct simulates the duct which isinstalled in ELTL, while other duct simulates the duct which
has been installed in Fusion Materials Irradiation Test Facility(FMIT). The visualized high-speed liquid flows under variousflow rates and vacuum conditions were obtained from the twokinds of the ducts in order to compare their performances.

70 mm

Fig.1 Over view of the experimental water flowing device.
(a)

(b)

Fig.2 Detail of the simulated piping.

Fig.3 Position of acceleration measured and sensors.
Accelerometer (sampling time: 20 kHz)

Fig.4 Data of accelerometer at 30kPa, 15 m/s.
Table 2 Experimental parameter
Pressure

Velocity(m/s)

Cavitation No.

3.00E+04
3.00E+04
3.00E+04
3.00E+04
1.00E+05
1.00E+05
1.00E+05
1.00E+05

810
121581012150.91
0.58
0.40
0.26
3.10
2.00
1.38
0.88

References[1] E.Wakai et al., “Development of Lithium Target System inEngineering Validation and Engineering Design Activity of theInternational Fusion Materials Irradiation Facility (IFMIF/EVEDA)”, J.

Fig.5 Ratio of acceleration rms