Mixed Thermocapillary and Forced Convection Heat Transfer Around a Hemispherical Bubble in a Miniature Channel—A 3D Numerical Study
Mixed Thermocapillary and Forced Convection Heat Transfer Around a Hemispherical Bubble in a Miniature Channel—A 3D Numerical Study
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微型通道中半球形气泡周围的混合热毛细管和强制对流换热 - 3D 数值研究
DOI：
10.1080/01457632.2012.630250
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
C. Rădulescu
中科院分区：
文献类型：
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作者：
C. Rădulescu
已经确定，在某些条件下，如微重力沸腾，热毛细马兰戈尼流与它相关的传热显著增强。通常，研究这种现象的理想情况是，一个孤立的、静止的气泡位于被加热的固体之上，浸入半无限静态流体或二维腔内。本文采用三维数值研究方法，研究了水在小通道层流过程中，热马兰戈尼对流对气泡周围流体动力学和换热的影响。研究了微重力条件下通道液体进口速度为0.01 m/s ~ 0.03 m/s， Marangoni数为10 ~ 300的混合热毛细和强制对流问题。三维效果在气泡的侧面和后部变得尤为重要。热毛细力几乎沿着整个气泡界面加速流动。来自加热底壁区域的热芯流体被强迫向内并向上推进到气泡上方的热毛细射流中。可以量化，热毛细流动对传热强化的影响在气泡下游平均增加40%，在气泡前后区域平均增加60%。这种传热增强主要取决于温差作为热毛细管流动和体液速度的驱动势。
It has been established that for certain conditions, such as microgravity boiling, thermocapillary Marangoni flow has associated with it a significant enhancement of heat transfer. Typically, this phenomenon was investigated for the idealized case of an isolated and stationary bubble resting atop a heated solid that is immersed in a semi-infinite quiescent fluid or within a two-dimensional cavity. This article presents a three-dimensional numerical study that investigates the influence of thermal Marangoni convection on the fluid dynamics and heat transfer around a bubble during laminar flow of water in a minichannel. This mixed thermocapillary and forced convection problem is investigated for channel liquid inlet velocity of 0.01 m/s to 0.03 m/s and Marangoni numbers in the range of 10 to 300 under microgravity conditions. Three-dimensional effects become particularly important on the side and rear regions of the bubble. The thermocapillary forces accelerate the flow along almost the entire bubble interface. The hot core fluid from the heated bottom wall region is forced inward and propelled upward into the thermocapillary jet above the bubble. It can be quantified that the influence of thermocapillary flow on heat transfer enhancement shows an average increase by 40% at the downstream of the bubble and by 60% at the front and rear regions. This heat transfer enhancement depends mainly on the temperature differential as the driving potential for thermocapillary flow and bulk liquid velocity.