{"title":"Flow boiling instability of R134a in the large-area heat sink with interconnected parallel multi-minichannels","authors":"Liaofei Yin, Youjun Wang, Li Jia","doi":"10.1016/j.ijthermalsci.2024.109193","DOIUrl":null,"url":null,"abstract":"<div><p>Flow boiling instability stands as one of the key factors hindering the engineering application of large-area heat sinks with parallel multi-minichannels. In this study, a novel large-area heat sink with one inlet and two outlets was fabricated with aluminum alloy. It included 50 parallel minichannels, which were interconnected by the micro-slots arrays to balance the fluid pressure and redistribute the two-phase flow during flow boiling. The working fluid selected for the study was R134a, upon which flow boiling experiments were subsequently carried out. The effects of the thermal-hydraulic parameters, such as pressure drop across the test section, inlet and outlet pressures, and wall temperatures, on the two-phase flow state during flow boiling were analyzed. The flow boiling instability criterion for large-area parallel multi-minichannels heat sink was proposed, and the flow instability map was created to predict the two-phase flow state. It was found that the ratio of heat flux to mass flux (<em>q</em><sub>w</sub>/<em>G</em>) was an important parameter for stable and unstable two-phase flow. The flow boiling instability first locally appeared in the region near the outlet and then expanded to the entirety of the heat sink's flow passage with the escalation of the <em>q</em><sub>w</sub>/<em>G</em> ratio. In addition, the characteristics of heat transfer and the transitions in flow patterns during flow boiling instability were also discussed.</p></div>","PeriodicalId":341,"journal":{"name":"International Journal of Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":4.9000,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Thermal Sciences","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1290072924003156","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Flow boiling instability stands as one of the key factors hindering the engineering application of large-area heat sinks with parallel multi-minichannels. In this study, a novel large-area heat sink with one inlet and two outlets was fabricated with aluminum alloy. It included 50 parallel minichannels, which were interconnected by the micro-slots arrays to balance the fluid pressure and redistribute the two-phase flow during flow boiling. The working fluid selected for the study was R134a, upon which flow boiling experiments were subsequently carried out. The effects of the thermal-hydraulic parameters, such as pressure drop across the test section, inlet and outlet pressures, and wall temperatures, on the two-phase flow state during flow boiling were analyzed. The flow boiling instability criterion for large-area parallel multi-minichannels heat sink was proposed, and the flow instability map was created to predict the two-phase flow state. It was found that the ratio of heat flux to mass flux (qw/G) was an important parameter for stable and unstable two-phase flow. The flow boiling instability first locally appeared in the region near the outlet and then expanded to the entirety of the heat sink's flow passage with the escalation of the qw/G ratio. In addition, the characteristics of heat transfer and the transitions in flow patterns during flow boiling instability were also discussed.
期刊介绍：
The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review.
The fundamental subjects considered within the scope of the journal are:
* Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow
* Forced, natural or mixed convection in reactive or non-reactive media
* Single or multi–phase fluid flow with or without phase change
* Near–and far–field radiative heat transfer
* Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...)
* Multiscale modelling
The applied research topics include:
* Heat exchangers, heat pipes, cooling processes
* Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries)
* Nano–and micro–technology for energy, space, biosystems and devices
* Heat transport analysis in advanced systems
* Impact of energy–related processes on environment, and emerging energy systems
The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.
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