Miniature optical fiber sensor used to measure the local void fraction.

Hinata, Shigeru; Venart, J. E. S.; Sousa, António C.M.; Sakurai, Masayuki; Nakazawa, Masari; Ichimura, Ichio

doi:10.1299/kikaib.56.1433

Cited by 5 publications

(6 citation statements)

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“…Danel and Delhaye developed a Ushaped probe with a thickness of 0.1 mm ͑Galaup, 23 Danel 24 ͒. Abuaf et al, 17 Hinata et al 25 fused together two fibers at one end and polished it, thus forming an included angle of 90°at the probe tip. Measurement in corrosive or erosive environments led Vince et al 26 and Stutz and Reboud 27 to use optical fibers wrapped in metal tubes and equipped with glued diamond or sapphire tips at their end.…”

Section: Introductionmentioning

confidence: 99%

Two-phase flow structure of sheet cavitation

1997

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Section: Introductionmentioning

confidence: 99%

Two-phase flow structure of sheet cavitation

1997

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“…One class of sensors is labeled as intrusive as they are in direct contact with the fluid. An example is the optical fiber probe [5,6,7] which is submerged into the flow and measures the void fraction on its tip based upon the changes in normal reflections when IR light encounters liquid-gas and gas-liquid interfaces. Another intrusive sensor is the wire mesh probe [5,8,9,10] based upon the change of electrical conductivity of a wire inserted in the fluid due to the presence of gas in the liquid.…”

Section: State-of-the-artmentioning

confidence: 99%

Void fraction measurement in cryogenic flows. Part I: Design and validation of a void fraction capacitive sensor

et al. 2018

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This manuscript presents the design of a capacitive void fraction sensor for cryogenic LN2 two phase flows and its validation at room conditions. The capacitive void fraction sensor is first designed by means of Electric Field Analysis (EFA) simulations taking into account specific technical constraints coming from the test section in which it should be accommodated. Then it is manufactured and validated using a proper combination of fluids (Polydimethylsiloxane (PDMS) and air) having a dielectric constant ratio similar to the one encountered in LN2/GN2 two phase flows. The validation is performed through comparison with void fraction measured by means of optical visualizations and shows how the capacitive measurement technique robustness allows obtaining reasonable accurate values of void fraction also for the substitute fluid case. The sensor presented in this manuscript was used to evaluate the void fraction during LN2 chilldown of a rectangular cooling channel and the results are presented in the second part of this work.

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“…In this simulation, only the section between and is taken into consideration. The total differential capacitance, , consists of that of the tube, , and that of the fluid within the slice , by (2) Integrating over from to , we have where is related to by (4) and is a function of the void fraction, , expressed by (5) Fig. 9.…”

Section: Temperature Drift Analysis 331 Shu's Theorymentioning

confidence: 99%

“…In this field, many researches have been performed focusing on methods for measuring the void fraction [4][5][6][7][8][9][10] . These methods are commonly used in chemical or atomic power plants; however, there is little application on the cryogenic two phase flow.…”

Section: Introductionmentioning

confidence: 99%

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Void Fraction Measurement of Cryogenic Two Phase Flow Using a Capacitance Sensor

Maeno

Okada

Kitakoga

et al. 2014

AEROSPACE TECHNOLOGY JAPAN

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A new capacitance type void fraction sensor was designed, produced, and tested. This sensor applies the difference between the relative permittivity of gaseous hydrogen ( = 1.0) and that of liquid hydrogen ( = 1.2). Following the sensor verification test using light diesel oil and air, a cryogenic experiment using liquid nitrogen was conducted. As a result, the void fraction measured by the sensor showed good agreement with the result obtained by an optical analysis using a high speed camera. One of the key problems on the sensor is an existence of the temperature drift caused by the change of the relative permittivity of the glass tube. In order to reduce the temperature drift, the length of electrodes and material of tubes were changed. Combination of short arc length electrodes and iupilon tube is ideal for reducing the unwanted temperature drift. The sensor which has shorter electrodes reduces the quantity of the temperature drift by 63% compared to the original sensor.

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Miniature optical fiber sensor used to measure the local void fraction.

Cited by 5 publications

References 0 publications

Two-phase flow structure of sheet cavitation

Two-phase flow structure of sheet cavitation

Void fraction measurement in cryogenic flows. Part I: Design and validation of a void fraction capacitive sensor

Void Fraction Measurement of Cryogenic Two Phase Flow Using a Capacitance Sensor

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