Xiaoyuan Yang , Bingyao Huang , Yi Zhang , Tianyou Lian , Lang Luo , Yuyang Li
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Both boiling behaviors are featured with the violent breakup of parent droplet into about 10 or more fragment droplets (secondary droplets with <em>D</em> ≥ 0.3 mm) and the short residence times on the wall, while exhibiting different splash angle distributions of satellite droplets (secondary droplets with <em>D</em> < 0.3 mm). Characteristic parameter analysis of the two boiling behaviors is conducted to provide qualitative mechanistic explanations. Corona boiling occurs at <em>Φ</em><sub>e</sub> = 25% & 50% with a lower temperature range (<em>T</em><sub>s</sub> ≤ 200 ℃), the liftoff of the liquid layer is attributed to the combined effect of decelerated wetting speed caused by evaporation and the vapor-induced lift. Prompt boiling occurs at <em>Φ</em><sub>e</sub> = 25% & 50% with <em>T</em><sub>s</sub> ≥ 220 °C and <em>Φ</em><sub>e</sub> = 75% with <em>T</em><sub>s</sub> < 200 °C, the intensity of the bubble cloud determines whether the central part of the droplet forms a jet or a liquid bulk filled with microbubbles. 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引用次数: 0
摘要
本研究利用高速成像系统对水/乙醇二元液滴撞击加热的光滑铝合金板的过渡沸腾行为进行了实验研究,形成了更精细的撞击行为体系图。动态莱顿弗罗斯特点温度与乙醇分数呈非单调变化趋势。二元液滴在特定温度(Ts)和液滴成分(Φe)下表现出两种特征性沸腾行为,包括电晕沸腾和迅速沸腾,分别表现为冠状厚液层的升高和从接触线迅速产生大量次级液滴。这两种沸腾行为的特点都是母液滴剧烈破裂成约 10 个或更多的碎片液滴(D ≥ 0.3 mm 的次级液滴),在液滴壁上的停留时间很短,而卫星液滴(D < 0.3 mm 的次级液滴)则表现出不同的飞溅角分布。我们对这两种沸腾行为进行了特征参数分析,以提供定性的机理解释。电晕沸腾发生在 Φe = 25% & 50% 的较低温度范围内(Ts ≤ 200 ℃),液层的升力归因于蒸发引起的湿润速度减慢和蒸汽引起的升力的共同作用。气泡云的强度决定了液滴的中心部分是形成射流还是形成充满微气泡的液块。这项工作将为二元溶液液滴的沸腾行为和二次雾化调节影响研究提供一些新的见解。
Characterizing boiling behaviors in water/ethanol binary droplet impact on a heated plate
This work experimentally investigates the transition boiling behaviors of water/ethanol binary droplets impact on a heated smooth aluminum alloy plate with a high-speed imaging system, forming a more finely defined impact behavior regime map. The dynamic Leidenfrost point temperature exhibits a non-monotonic variation trend with ethanol fraction. Binary droplets exhibit two characteristic boiling behaviors at specific temperatures (Ts) and droplet compositions (Φe), including corona boiling and prompt boiling, distinguished by the elevation of a crown-shaped thick liquid lamella and the prompt generation of numerous secondary droplets from the contact line, respectively. Both boiling behaviors are featured with the violent breakup of parent droplet into about 10 or more fragment droplets (secondary droplets with D ≥ 0.3 mm) and the short residence times on the wall, while exhibiting different splash angle distributions of satellite droplets (secondary droplets with D < 0.3 mm). Characteristic parameter analysis of the two boiling behaviors is conducted to provide qualitative mechanistic explanations. Corona boiling occurs at Φe = 25% & 50% with a lower temperature range (Ts ≤ 200 ℃), the liftoff of the liquid layer is attributed to the combined effect of decelerated wetting speed caused by evaporation and the vapor-induced lift. Prompt boiling occurs at Φe = 25% & 50% with Ts ≥ 220 °C and Φe = 75% with Ts < 200 °C, the intensity of the bubble cloud determines whether the central part of the droplet forms a jet or a liquid bulk filled with microbubbles. This work will provide some new insights into the boiling behaviors and the regulation of secondary atomization of binary solution droplets impact studies.
期刊介绍:
Experimental Thermal and Fluid Science provides a forum for research emphasizing experimental work that enhances fundamental understanding of heat transfer, thermodynamics, and fluid mechanics. In addition to the principal areas of research, the journal covers research results in related fields, including combined heat and mass transfer, flows with phase transition, micro- and nano-scale systems, multiphase flow, combustion, radiative transfer, porous media, cryogenics, turbulence, and novel experimental techniques.