Comparison between modelled and measured heat transfer rates during the departure of a steam bubble from a solid surface
Comparison between modelled and measured heat transfer rates during the departure of a steam bubble from a solid surface
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蒸汽泡离开固体表面期间模拟传热率与测量传热率的比较
DOI：
10.1016/j.ijheatmasstransfer.2019.119092
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发表时间：
2020
影响因子：
5.2
通讯作者：
Giustini G
中科院分区：
文献类型：
--
作者：
Giustini G
本文分析了常压水池沸腾过程中单个汽泡脱离时的传热过程。从固体表面到液态水的流动的热量在气泡剥离期间和之后立即已提取从微尺度测量的空间和时间变化的温度在固体表面下的气泡。用于提取的固体表面的温度变化的热通量的数值程序已被评估和验证，并施加到调查的气泡离开阶段的传热过程中，并在最终的气泡升空。结果证实，由离去的气泡激活的流体运动是传热增强的原因。这种现象的特征在于，通过前进的液体前沿，在气泡底部的壁区域的干燥部分的再润湿过程。已经发现，受所观察到的传热增强机制影响的壁面积的部分是直径大致等于气泡离开直径的一半的圆的部分。当前的测量使得能够验证单个气泡形成和离开表面的流体动力学和传热的界面捕获数值模拟，包括固体基质中的共轭传热。从模拟结果中，空间和时间变化的热通量在气泡下方的固体表面已被计算和监测在气泡离开和最终气泡升空后。从模拟中提取的气泡离开时的传热速率已被发现与测量结果吻合良好。模拟正确地捕捉到实验趋势，并被发现给一个准确的估计的大小的流动的热量的液体，由于在附近的壁所造成的气泡离开过程中的冷流体。
This paper presents analysis of the heat transfer attendant upon the departure of a single steam bubble during pool boiling of water at atmospheric pressure. The flow of heat from a solid surface to liquid water during and immediately after bubble lift-off has been extracted from micro-scale measurements of the spatial and temporal variation of the temperature at the solid surface beneath the bubble. The numerical procedure used to extract the heat flux from the temperature variations at the solid surface has been assessed and verified, and applied to investigate the heat transfer during the bubble departure phase, and after the eventual bubble lift-off. Results confirm that fluid motion activated by a departing bubble is the cause of heat transfer enhancement. The phenomenon can be characterised as the process of rewetting, by an advancing liquid front, of a dry portion of wall area at the base of the bubble. The portion of wall area that is affected by the observed heat transfer augmentation mechanism has been found to be that of a circle of diameter roughly equal to half the bubble departure diameter. The current measurements enabled validation of interface-capturing numerical simulation of the hydrodynamics and heat transfer of single bubble formation and departure from a surface, including conjugate heat transfer in the solid substrate. From simulation results, the spatial and temporal variation of the heat flux at the solid surface beneath the bubble has been computed and monitored during bubble departure and after the eventual bubble lift-off. Heat transfer rates at bubble departure extracted from simulation have been found in good agreement with measurements. The simulation correctly captured experimental trends and was found to give an accurate estimate of the magnitude of the flows of heat to the liquid due to the bringing of cold fluid in the vicinity of the wall caused by the bubble departure process.
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使用平衡热力学模拟流动沸腾中的气泡离开
DOI：
10.1016/j.ijheatmasstransfer.2018.02.057
发表时间：
2018
影响因子：
5.2
作者：
Giustini G
通讯作者：
Giustini G
DOI：
--
发表时间：
2006
期刊：
--
影响因子：
--
作者：
Werner Hässelbarth;M. Golze;Siegfried Noack;A. Subaric-Leitis
通讯作者：
Werner Hässelbarth;M. Golze;Siegfried Noack;A. Subaric-Leitis
影响因子：
4.1
作者：
BRACKBILL, JU;KOTHE, DB;ZEMACH, C
通讯作者：
ZEMACH, C
影响因子：
4.1
作者：
Fabian Denner;B. Wachem
通讯作者：
B. Wachem
影响因子：
15.6
作者：
Malgarinos, Ilias;Nikolopoulos, Nikolaos;Gavaises, Manolis
通讯作者：
Gavaises, Manolis