Thermal characteristics of double tube two-phase thermosyphon.

Fukuda, Kenji; Hasegawa, Shuichi; Kondoh, Tetsuya; Nakagawa, Kiyoshi; Tamura, Shun; Okabe, Kazuya

doi:10.1299/kikaib.57.687

Cited by 3 publications

(2 citation statements)

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“…Various experimental investigations of energy transport properties using water, R113, ethanol, and nitrogen for the refrigerant, and formulation of prediction relations are progressing for establishing the design of the concentric-tube twophase thermosyphon (Fukuda et al, 1991;Imura et al, 1990;Inoue et al, 2013;Monde et al, 1998). However, it is necessary to use sodium at 960 K for application to heat transportation of a reactor (Kimura et al, , 2019Yoshida et al, 2016;Wada et al, 2016), and further elucidation of the flow phenomenon is necessary to establish its performance prediction model.…”

Section: Introductionmentioning

confidence: 99%

Study on the flow and heat transport characteristics of concentric-tube two-phase thermosyphon

Hongo

Miyachi

Kimura

et al. 2020

Mechanical Engineering Journal

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Two-phase thermosyphons, which use sodium at 960 K as a refrigerant for heat transportation in small nuclear reactors, are promising for manned exploration to Mars. This is because the concentric-tube type thermosyphon may not have a flooding limit, and so the heat transfer performance per unit volume is comparatively large. Moreover, since its external form is a single tube by inserting a pipe through which the liquid flows into a pipe through which the gas flows, the reactor core can be made smaller. Experimental investigations of heat transport characteristics using water, R113, ethanol, and nitrogen as refrigerants and development of prediction formulas are progressing for establishing the design of the concentric-tube two-phase thermosyphon. However, it is necessary to use sodium at 960 K for application to heat transportation of a reactor, and further elucidation of the flow phenomenon is necessary to establish its performance prediction model. We have proposed a model based on bubble pump theory in order to take into consideration the rise of liquid level of the heating section. We conducted an experimental study on the flow inside a thermosyphon made of transparent material, and evaluated the maximum heat transfer rate using a low boiling point refrigerant, HFE-7100. As a result, even when the heat transfer rate was close to the maximum, it was shown that the flow regime in the outer tube of the adiabatic section of the concentric tube is two-phase flow. However, the experimental value of the maximum heat transfer rate was found to be about 17 % smaller than the calculated value. We therefore investigated the cause of this difference by making pressure measurements and flow observations, and found that bubble entrainment in the inner tube of the concentric tube of the adiabatic section greatly influences the pressure distribution. It is thought that taking mixing into consideration would help improve the model.

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Section: Introductionmentioning

confidence: 99%

Study on the flow and heat transport characteristics of concentric-tube two-phase thermosyphon

Hongo

Miyachi

Kimura

et al. 2020

Mechanical Engineering Journal

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“…It has been reported that, in a two-phase thermosyphon, the critical heat flux is increased markedly by insertion of an inner tube with an appropriate top-end shape into the heated tube (Fukuda et al, 1988, andFukuda et al,1989). The authors also performed an experimental study on two-phase double-tube thermosyphons with inner tubes of various top-end shapes using three kinds of working fluids (water, ethanol, and Freon 113), and showed that for Freon 113 the critical heat flux increased more than four times that without the inner tube, when the inner tube had a Tshape top-end or a plate disk at the top (Imura and Yoshida, 1990).…”

Section: Introductionmentioning

confidence: 99%

Flow and Heat Transfer in a Two-Phase Double-Tube Thermosyphon

Imura

Yoshida

1992

Transport Phenomena in Heat and Mass Transfer

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Thermophysical relationships for waste heat recovery using looped heat pipes

Lamfon

Akyurt

Najjar

et al. 1994

Int. J. Energy Res.

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A scheme is described for the recovery of waste heat from stacks of gas turbine engines by means of heat‐pipe loops. The recovered energy is supplied to an absorption chiller that cools the intake air of the gas turbine engine to enhance its performance. Mathematical expressions are introduced which accurately portray existing tabulated thermophysical properties data for those variables needed during the modelling of the said system.

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Thermal characteristics of double tube two-phase thermosyphon.

Cited by 3 publications

References 0 publications

Study on the flow and heat transport characteristics of concentric-tube two-phase thermosyphon

Study on the flow and heat transport characteristics of concentric-tube two-phase thermosyphon

Flow and Heat Transfer in a Two-Phase Double-Tube Thermosyphon

Thermophysical relationships for waste heat recovery using looped heat pipes

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