Nucleate boiling of low-concentration alcohol aqueous solutions for the development of thermal management systems in space

Ohta, Hiroyuki; Yamaguchi, Shunpei; Ito, Yoshihiko; Shinmoto, Yasuhisa; Abe, Yoshiyuki

doi:10.1007/bf02915779

Cited by 10 publications

(6 citation statements)

References 10 publications

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“…Although the expected increase in CHF due to the inflow of cold liquid toward the boiling surface was confirmed for confined spaces and restricted boiling surfaces (wires, microchannels, etc.) [55,56], the results for flat surfaces are ambiguous and unpredictable [55,57,58]. Research on the pool boiling of SRFs on modified surfaces is scarce.…”

Section: Self-rewetting Fluidsmentioning

confidence: 99%

Hydrophilic and Hydrophobic Nanostructured Copper Surfaces for Efficient Pool Boiling Heat Transfer with Water, Water/Butanol Mixtures and Novec 649

et al. 2021

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Increasing heat dissipation requirements of small and miniature devices demands advanced cooling methods, such as application of immersion cooling via boiling heat transfer. In this study, functionalized copper surfaces for enhanced heat transfer are developed and evaluated. Samples are functionalized using a chemical oxidation treatment with subsequent hydrophobization of selected surfaces with a fluorinated silane. Pool boiling tests with water, water/1-butanol mixture with self-rewetting properties and a novel dielectric fluid with low GWP (Novec™ 649) are conducted to evaluate the boiling performance of individual surfaces. The results show that hydrophobized functionalized surfaces covered by microcavities with diameters between 40 nm and 2 µm exhibit increased heat transfer coefficient (HTC; enhancements up to 120%) and critical heat flux (CHF; enhancements up to 64%) values in comparison with the untreated reference surface, complemented by favorable fabrication repeatability. Positive surface stability is observed in contact with water, while both the self-rewetting fluids and Novec™ 649 gradually degrade the boiling performance and in some cases also the surface itself. The use of water/1-butanol mixtures in particular results in surface chemistry and morphology changes, as observed using SEM imaging and Raman spectroscopy. This seems to be neglected in the available literature and should be focused on in further studies.

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Section: Self-rewetting Fluidsmentioning

confidence: 99%

Hydrophilic and Hydrophobic Nanostructured Copper Surfaces for Efficient Pool Boiling Heat Transfer with Water, Water/Butanol Mixtures and Novec 649

et al. 2021

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“…McGillis and Carey [23] realized that the variation of CHF was closely connected with the component concentration in the mixtures which was predominantly affected by the surface tension gradient such as Marangoni effect. Ohta et al [32] argued that the self-wetting characteristics of binary mixtures could lead to boiling heat transfer enhancement, though most other relevant studies showed otherwise. In their study, Binary mixtures with superior self-wetting characteristics were selected as the working fluid.…”

Section: Marangoni Effectmentioning

confidence: 99%

A review of boiling heat transfer characteristics in binary mixtures

Wang

Yang

et al. 2021

International Journal of Heat and Mass Transfer

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This paper reviews the state-of-the-art knowledge of boiling heat transfer in binary mixtures, special emphasis is placed on refrigeration industry. The advantage of using refrigerant mixtures over pure refrigerants include the enhancement of coefficient of performance (COP), better match with the desired thermal load and safer, more environmental-friendly refrigerants. In other words, the concept of using mixtures enables more flexibility for the selection of suitable working fluids in particular applications. The purpose of this review article aims to summarize the important published articles on boiling heat transfer in binary mixtures and innovative technologies, as well as to identify limitations to existing studies and directions for future research of this promising thermal management technique. The present article reviews straightforward on both pool boiling and flow boiling in a systematic and comprehensive way. This article maily focus on the review of the effects of mass diffusion, heating surface characteristics, heats from dilution and dissolution on pool boiling heat transfer of binary mixtures, as well as the effects of flow orientation, flow regime and flow instability on flow boiling heat transfer of binary mixtures. Many papers reviewed herein relate to the heat transfer correlations during boiling of binary mixtures. The review reveals that numerical simulations of boiling in binary mixtures, the benefits of surface modification on boiling of binary mixtures and the flow boiling of highly viscous pseudo-plastic mixtures have been scarcely investigated and require further investigation.

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“…[25,27]) and space systems, as per Refs. [28,29]. Generally speaking, self-rewetting liquids could be beneficial to multiple thermal management systems relying on pool boiling.…”

Section: Introductionmentioning

confidence: 99%

Pool boiling in deep and shallow vessels and the effect of surface nano-texture and self-rewetting

Sankaran

Zhang

Yarin

2018

International Journal of Heat and Mass Transfer

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Pool boiling of ethanol and self-rewetting fluids on bare copper surface and copper surface with polymer nanofibers were studied experimentally. No significant effect of the depths of ethanol layer on the heat removal rate was found. That indicates that only the heat transfer in the liquid microlayer near the heater surface is a dominant factor. As a result, one can expect that selfrewetting fluids can significantly affect boiling performance. Accordingly, several alcohol solutions including the self-rewetting ones were investigated as working fluids in the boiling chamber. It was found that at the 0.1% (v/v) concentration, only the high carbon-alcohol, nheptanol in aqueous solution, improved boiling heat transfer considerably. Furthermore, the experimental study of the effect of surface nano-texture on boiling characteristics was undertaken. For that aim, polyacrylonitrile (PAN) nanofibers were deposited onto the copper heater surface. Measurements of the boiling curve revealed a detrimental effect of such nano-texture in the case of such working fluids as ethanol and self-rewetting n-heptanol solutions. On the other hand, when polystyrene (PS) nanofibers were deposited onto the copper heater surface instead of PAN nanofibers, a significant improvement in boiling heat transfer was observed. The more hydrophobic nature of PS compared to copper is responsible for this effect, i.e. is the reason of the heat transfer enhancement on such a nano-textured surface compared to the pure copper one. In addition, the critical heat flux in the case of n-heptanol solution was found to be reduced considerably on the PS nano-textured surface compared to the pure copper one. This stems from the increased propensity of the heater surface to be covered by vapor, while the rewetting is insufficiently effective at high heat fluxes in presence of PS nanofibers.

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Nucleate boiling of low-concentration alcohol aqueous solutions for the development of thermal management systems in space

Cited by 10 publications

References 10 publications

Hydrophilic and Hydrophobic Nanostructured Copper Surfaces for Efficient Pool Boiling Heat Transfer with Water, Water/Butanol Mixtures and Novec 649

Hydrophilic and Hydrophobic Nanostructured Copper Surfaces for Efficient Pool Boiling Heat Transfer with Water, Water/Butanol Mixtures and Novec 649

A review of boiling heat transfer characteristics in binary mixtures

Pool boiling in deep and shallow vessels and the effect of surface nano-texture and self-rewetting

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