Vertical coalescence during nucleate boiling from a single artificial cavity
Vertical coalescence during nucleate boiling from a single artificial cavity
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DOI：
10.1016/j.expthermflusci.2013.07.005
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发表时间：
2013-11
影响因子：
3.2
通讯作者：
C. Hutter;A. Sanna;T. Karayiannis;D. Kenning;R. A. Nelson;K. Sefiane;A. Walton
中科院分区：
文献类型：
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作者：
C. Hutter;A. Sanna;T. Karayiannis;D. Kenning;R. A. Nelson;K. Sefiane;A. Walton
在这项实验研究中，我们研究了在380μm厚的硅片上微加工的孤立人工腔中气泡的生长。水平方向的沸腾表面由集成在硅测试部分背面的薄电阻加热器加热。利用位于沸腾表面的集成微型传感器测量温度，人造空腔位于其几何中心。为了进行饱和水池沸腾实验，测试部分被浸泡在脱气的氟惰性FC-72中。利用高速成像和温度传感器分析了不同压力下气泡的成核、长大、剥离和蒸发热流密度。在孤立气泡和干扰区域之间的边界处最初观察到垂直合并。对于孤立气泡区域以外的壁面过热，垂直聚结的发生随着压力的增加而减少。尽管随着壁面过热度的增加，垂直聚结最初似乎更加频繁，但数据的散布性质掩盖了对温度的明显依赖。将施加的热通量与蒸发热通量进行比较，名义上基于对沸腾基材的任意选择的影响区域。
In this experimental study bubble growth from an isolated artificial cavity micro-fabricated on a 380 μm thick silicon wafer was investigated. The horizontally oriented boiling surface was heated by a thin resistance heater integrated on the rear of the silicon test section. The temperature was measured using an integrated micro-sensor situated on the boiling surface with the artificial cavity located in its geometrical centre. To conduct saturated pool boiling experiments the test section was immersed in degassed fluorinert FC-72. Bubble nucleation, growth, detachment and the evaporative heat flux at different pressures were analysed using high-speed imaging and temperature micro-sensors. Vertical coalescence was initially observed at the boundary between the isolated bubble and interference regimes. For wall superheats outside the isolated bubble regime, the occurrence of vertical coalescence is decreasing with increasing pressure. Although vertical coalescence seems initially more frequent with increasing wall superheat, the explicit dependency on temperature is covered by the scattering nature of the data. The applied heat flux was compared to the evaporative heat flux, nominally based on an arbitrary chosen area of influence on the boiling substrate.