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气泡从基板上脱离的运动规律，对于研究核态沸腾的机理及相变传热有着重要意义。利用Level Set方法建立二维轴对称非稳态模型对该问题进行数值模拟，获得气泡在浮力、黏性力、惯性力与表面张力共同作用下的运动规律，分析不同Re数、Bo数和表面润湿性对气泡脱离基板规律的影响，并获得气泡从基板脱离时的临界参数。结果发现，当Re数增大，气泡上升的惯性力就增大，气泡越容易脱离；当Bo数增加，气泡会从完全脱离转变为部分脱离；随着表面润湿性的降低，气泡与基板的接触面积增大，气泡与基板及附近液体的作用力就增大，越难以脱离。 相似文献
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为研究特殊润湿性网膜材料的油水分离特性，通过原位置换和氧化修饰方法，以铜网为基底分别制备Ag和Cu（OH）2微纳米结构的超亲水/水下超疏油网膜。实验对比分析两种网膜油水分离效率、膜通量和稳定性等指标，着重研究微观结构、表面润湿性、入侵压力及介质酸碱性等因素对网膜分离性能的影响。结果表明：两种网膜对柴油、汽油等单油相和多组分混合油相的油水混合物的分离效率均达到99%以上。由于两种网膜的微观结构不同，Ag微纳米结构网膜分离效率略优于Cu（OH）2结构网膜，但Cu（OH）2微纳米结构网膜能够承受的入侵压力更大，且其膜通量更优。两种网膜都具有较优异的耐强碱和非氧化性酸性能。此外，两种网膜在清洗后能重复使用10次以上而效率没有明显降低，并且长期放置后两种网膜分离效率没有明显的降低。总之，这两种网膜无论是在分离效率、介质适应性，还是在重复性、耐久性等方面都具有各自明显优势，应用前景广阔。 相似文献
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受自然界荷叶等表面超疏水现象的启发,结合科研成果,基于固-液界面润湿性相关的理论知识,将超疏水铜网表面的结构设计、制备及其在油水分离中应用研究引入到实验教学中。利用电化学沉积和化学还原两步法在铜网表面构建粗糙的微纳米结构,再将表面以正十二硫醇修饰,制备具有超疏水特性的铜网,将其应用于油水分离。另外,在实验课程中设置结果的分析讨论环节,巩固和验证理论知识点的同时加强学生对实验细节的观察能力。将科研成果回馈教学,这对于丰富教学实验项目、培养学生创新思维、提高学生学习效率、培养复合型人才具有重要的意义。 相似文献
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Knowledge of intrinsic wettability at solid/liquid interfaces at the molecular level perspective is significant in understanding crucial progress in some fields, such as electrochemistry, molecular biology and earth science. It is generally believed that surface wettability is determined by the surface chemical component and surface topography. However, when taking molecular structures and interactions into consideration, many intriguing phenomena would enrich or even redress our understanding of surface wettability. From the perspective of interfacial water molecule structures, here, we discovered that the intrinsic wettability of crystal metal oxide is not only dependent on the chemical components but also critically dependent on the crystal faces. For example, the crystal face of α-Al2O3 is intrinsically hydrophobic with a water contact angle near 90°, while another three crystal faces are intrinsically hydrophilic with water contact angles <65°. Based on surface energy analysis, it is found that the total surface energy, polar component and Lewis base portion of the hydrophobic crystal face are all smaller than the other three hydrophilic crystal faces indicating that they have different surface states. DFT simulation further revealed that the adsorbed interfacial water molecules on each crystal face hold various orientations. Herein, the third crucial factor for surface wettability from the perspective of the molecular level is presented, that is the orientations of adsorbed interfacial water molecules apart from the macro-level chemical component and surface topography. This study may serve as a source of inspiration for improving wetting theoretical models and designing controllable wettability at the molecular/atomic level. 相似文献
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