A General Model for the Longevity of Super-Hydrophobic Surfaces in Under-Saturated, Stationary Liquid
A General Model for the Longevity of Super-Hydrophobic Surfaces in Under-Saturated, Stationary Liquid
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DOI：
10.1115/1.4053678
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发表时间：
2022-01
期刊：
影响因子：
--
通讯作者：
Aleksey Bourgoun;Hangjian Ling
中科院分区：
文献类型：
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作者：
Aleksey Bourgoun;Hangjian Ling
我们在不饱和的静止液体中对超疏水表面（SHS）的寿命进行了数值研究。数值求解了液体中气体浓度的时空演化、出板体气体质量通量的时间变化以及板体中气体完全溶解所需的时间（即板体寿命）。我们发现不同时刻的气体浓度分布是自相似的，质量通量随时间(t)以1/t0.5的速率减小。此外，我们研究了织构参数，包括沥青、气体分数、织构高度和高级接触角，对扩散过程的影响。结果表明：随着气相含量和织构高度的增加，膜层寿命和扩散长度均增加，与超前接触角和节距无关；我们提出了简单的板寿命和扩散长度的分析模型。结果表明，该模型与文献中报道的实验数据吻合较好，可以预测不同纹理几何形状、纹理尺寸和不同欠饱和程度下SHS的寿命。我们的模型可以指导水下应用的长寿命SHS的设计，例如减少皮肤摩擦阻力和防止生物污染。
We perform a numerical study of the longevity of a super-hydrophobic surface (SHS) in under-saturated, stationary liquid. We numerically solve the spatial-temporal evolution of the gas concentration in the liquid, the time-variation of mass flux of gas out of the plastron, as well as the time required for the gas in the plastron to be fully dissolved (i.e., the plastron lifetime). We find that the profiles of gas concentration at different times are self-similar, and the mass flux reduces with time (t) at a rate of 1/t0.5. In addition, we examine the impact of texture parameters, including pitch, gas fraction, texture height, and advanced contact angle, on the diffusion process. Our results show that both plastron lifetime and diffusion length increase with increasing the gas fraction or increasing the texture height, and are independent of the advanced contact angle and pitch. We propose simple analytical models for plastron lifetime and diffusion length. We show that the model has a fair agreement with the experimental data reported in the literature, and can predict the longevity for SHS with various texture geometries, texture sizes, and under different degrees of under-saturations. Our models could guide the design of long-life SHS for underwater applications such as reducing skin-friction drag and preventing biofouling.