Experimental studies of the effect of functional spacers to annular flow in subchannels of a BWR fuel element

Damsohn, Manuel; Prasser, Horst-Michael

doi:10.1016/j.nucengdes.2010.05.032

Cited by 43 publications

(11 citation statements)

References 7 publications

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“…Several studies [1,2] have demonstrated the method of liquid film thickness recovery to deposit liquid droplets in a gas core in two-phase annular flow to fuel rod by mixing vanes (MVs) attached on a spacer. Computational fluid dynamics (CFD) codes, which can analyze flows in detail based on CFD, have been developed to treat the droplet transfer, that is, the entrainment and deposition of the droplet for steam-water annular flow in the rod bundle.…”

Section: Introductionmentioning

confidence: 99%

Effects of grid spacer with mixing vane on entrainments and depositions in two-phase annular flows

Kawahara

Sadatomi

Imamura

et al. 2015

Nuclear Engineering and Technology

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a b s t r a c tThe effects of mixing vanes (MVs) attached to a grid spacer on the characteristics of air ewater annular flows were experimentally investigated. To know the effects, a grid spacer with or without MV was inserted in a vertical circular pipe of 16-mm internal diameter. For three cases (i.e., no spacer, spacer without MV, and spacer with MV), the liquid film thickness, liquid entrainment fraction, and deposition rate were measured by the constant current method, single liquid film extraction method, and double liquid film extraction method, respectively. The MVs significantly promote the re-deposition of liquid droplets in the gas core flow into the liquid film on the channel walls. The deposition mass transfer coefficient is three times higher for the spacer with MV than for the spacer without MV, even for cases 0.3-m downstream from the spacer. The liquid film thickness becomes thicker upstream and downstream for the spacer with MV, compared with the thickness for the spacer without MV and for the case with no spacer.

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Section: Introductionmentioning

confidence: 99%

Effects of grid spacer with mixing vane on entrainments and depositions in two-phase annular flows

Kawahara

Sadatomi

Imamura

et al. 2015

Nuclear Engineering and Technology

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“…• C was visualized as a movie with a high-speed liquid film sensor [2]. The dynamic film behavior around a half cylinder was captured.…”

Section: Introductionmentioning

confidence: 99%

Preliminary test of an ultrasonic liquid film sensor for high-temperature steam–water two-phase flow experiments

Aoyama

Nagayoshi

Baba

2014

Journal of Nuclear Science and Technology

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A prototype liquid film sensor for high-temperature steam-water experiments has been developed. The sensor shape simulates a boiling water reactor (BWR) fuel rod. The pulse-echo method can be utilized to measure the thickness of the liquid film covering the sensor surface. A piezoelectric element is soldered onto the inside of the sensor casing which consists of two curved casing pieces. After the piezoelectric element is attached, the two casing pieces are laser welded together. It is confirmed that the temperature rise at the time of the laser welding does not influence soldering of the piezoelectric element. The pressure proof test shows that the sensor can be used at a high-pressure condition of 7 MPa. Simple air-water experiments are done at atmospheric pressure to confirm the liquid film thickness can be measured with the sensor. The fluctuation of the liquid film thickness is satisfactorily captured with the sensor. The minimum and maximum thicknesses are 0.084 and 0.180 mm, respectively. The amplitude of the waveform at 286• C is predicted by the calculation based on the acoustic impedance. It is expected that the sensor is able to measure the liquid film thickness even at BWR operating conditions.

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“…In addition, this sensor was applied to the annular flow measurement in the double subchannels of a square-lattice bundle. The liquid film behavior in the rod bundle was well visualized (Damsohn & Prasser, 2010). Thus, the novel measurement method for two-phase flow in the narrow channel has been developed by combining the void fraction detection and liquid film sensor (Ito et al, 2011c).…”

Section: Introductionmentioning

confidence: 99%

Measurement of Two-Phase Flow Structure in a Narrow Rectangular Channel

Ito¹,

Prasser²

2012

Flow Measurement

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Experimental studies of the effect of functional spacers to annular flow in subchannels of a BWR fuel element

Cited by 43 publications

References 7 publications

Effects of grid spacer with mixing vane on entrainments and depositions in two-phase annular flows

Effects of grid spacer with mixing vane on entrainments and depositions in two-phase annular flows

Preliminary test of an ultrasonic liquid film sensor for high-temperature steam–water two-phase flow experiments

Measurement of Two-Phase Flow Structure in a Narrow Rectangular Channel

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