Numerical study on the local aggregation of helium bubbles in liquid lithium and its thermal analysis

IF 17.7 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Accounts of Chemical Research Pub Date : 2024-05-03 DOI:10.1115/1.4065467

Yongfu Liu, Yi He, Peng Tan

{"title":"Numerical study on the local aggregation of helium bubbles in liquid lithium and its thermal analysis","authors":"Yongfu Liu, Yi He, Peng Tan","doi":"10.1115/1.4065467","DOIUrl":null,"url":null,"abstract":"\n Liquid lithium is widely regarded as an optimal cooling medium for space nuclear reactors due to its exceptional heat transfer properties and low density. However, the helium bubbles generated by liquid lithium under space irradiation pose significant hazards to the safe and stable operation of nuclear reactions. In this study, the localized accumulation of helium bubbles in liquid lithium is investigated using a two-phase flow turbulence model. The effects of helium bubble distribution and inlet velocities on various parameters in the pipeline are focused on. A non-isothermal model for bubble flow is developed to examine the influence of gas-liquid mixture concentrations on overall heat transfer performance under low concentration conditions. Agglomerated bubbles with radii between 5 μm and 150 μm are classified into three categories based on local concentrations: circular (≤20.37%), irregular elongated (up to 30.44%), and banded (up to 36.31%). Interconnected banded bubbles can be up to 8 times larger than irregularly elongated ones, impacting physical properties and wall temperature disturbance in the pipeline. Elevated inlet velocity initiates the occurrence of bubble impact and fragmentation. However, high flow rates near the wall do not diminish wall temperature disturbance. Mixed flows with bubbles scales <15 μm show no significant impact on overall heat transfer up to 1% concentration. This study reveals the effects of bubble number and distribution, providing insights for manipulating bubble structure and guiding localized and comprehensive thermal analyses.","PeriodicalId":1,"journal":{"name":"Accounts of Chemical Research","volume":"66 2","pages":""},"PeriodicalIF":17.7000,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Accounts of Chemical Research","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1115/1.4065467","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

Liquid lithium is widely regarded as an optimal cooling medium for space nuclear reactors due to its exceptional heat transfer properties and low density. However, the helium bubbles generated by liquid lithium under space irradiation pose significant hazards to the safe and stable operation of nuclear reactions. In this study, the localized accumulation of helium bubbles in liquid lithium is investigated using a two-phase flow turbulence model. The effects of helium bubble distribution and inlet velocities on various parameters in the pipeline are focused on. A non-isothermal model for bubble flow is developed to examine the influence of gas-liquid mixture concentrations on overall heat transfer performance under low concentration conditions. Agglomerated bubbles with radii between 5 μm and 150 μm are classified into three categories based on local concentrations: circular (≤20.37%), irregular elongated (up to 30.44%), and banded (up to 36.31%). Interconnected banded bubbles can be up to 8 times larger than irregularly elongated ones, impacting physical properties and wall temperature disturbance in the pipeline. Elevated inlet velocity initiates the occurrence of bubble impact and fragmentation. However, high flow rates near the wall do not diminish wall temperature disturbance. Mixed flows with bubbles scales <15 μm show no significant impact on overall heat transfer up to 1% concentration. This study reveals the effects of bubble number and distribution, providing insights for manipulating bubble structure and guiding localized and comprehensive thermal analyses.

查看原文

微信好友朋友圈 QQ好友复制链接

本刊更多论文

液态锂中氦气泡局部聚集的数值研究及其热分析

液态锂因其优异的传热性能和低密度而被广泛认为是空间核反应堆的最佳冷却介质。然而，液态锂在太空辐照下产生的氦气泡会对核反应的安全稳定运行造成严重危害。本研究利用两相流湍流模型研究了液态锂中氦气泡的局部聚集。重点研究了氦气泡分布和入口速度对管道中各种参数的影响。建立了气泡流动的非等温模型，以研究低浓度条件下气液混合物浓度对整体传热性能的影响。根据局部浓度，半径在 5 μm 至 150 μm 之间的团聚气泡分为三类：圆形（≤20.37%）、不规则细长形（高达 30.44%）和带状（高达 36.31%）。相互连接的带状气泡可比不规则拉长的气泡大 8 倍，从而影响管道的物理性质和管壁温度。入口流速升高会导致气泡撞击和破碎。然而，管壁附近的高流速并不会减少管壁温度扰动。气泡尺度小于 15 μm 的混合流在浓度达到 1%时对整体传热没有明显影响。这项研究揭示了气泡数量和分布的影响，为控制气泡结构以及指导局部和全面的热分析提供了启示。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文去求助

来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.