太阳能加热液滴在亲疏水表面“黏-滑”蒸发

doi:10.16085/j.issn.1000-6613.2018-1797

摘要/Abstract

摘要：

实验研究了亲水和疏水表面上太阳能加热去离子水及金纳米流体液滴三相接触线动力学。在亲水和疏水表面滴加2μL去离子水和纳米流体液滴，用一定功率太阳能模拟器照射液滴使其蒸发，期间采用高速摄像机实时记录液滴在不同表面上的蒸发过程。由MATLAB程序处理图像得到液滴在不同表面上蒸发过程中接触角和接触圆直径的动态变化过程。发现液滴接触线在不同亲疏水表面上存在不同运动特性。去离子水液滴在亲水表面上常接触面积模式和常接触角模式依次控制蒸发过程。去离子水液滴在疏水表面上都呈现出“黏-滑”蒸发特性，即液滴先以常接触面积模式蒸发，之后接触线快速滑动，接触线固定后再以常接触面积模式蒸发，依次往复。纳米流体液滴在亲水表面上主要以常接触面积蒸发模式为主，在疏水表面上同样呈现“黏-滑”蒸发特性。从液滴表面能角度出发，对液滴接触线“钉扎”和“去钉扎”过程进行详尽分析，得出基底润湿性和纳米颗粒沉积是影响液滴接触线在表面上运动的重要因素。

关键词: 太阳能, 液滴, 蒸发, 纳米流体, 传质, 润湿性

Abstract:

The dynamics of the three-phase contact line for deionized water and gold nanofluid droplets with solar heating were experimentally investigated using substrates of various wettability. 2μL deionized water and nanofluid droplets, irradiated by a certain power solar simulator, were added to the hydrophilic or hydrophobic surfaces. A high-speed camera was used to record the evaporation process of the droplets on different surfaces in real time. The images were processed by the MATLAB program to obtain the dynamic characteristics of the droplets on different surfaces during evaporation, including the contact angle and contact area diameter. It has been found that droplets have different dynamics of the three-phase contact line on the hydrophilic and hydrophobic surfaces. Deionized water droplets evaporation on the hydrophilic surface was controlled by the constant contact area mode and the constant contact angle mode sequentially. Deionized water droplets exhibit “stick-slip” evaporation characteristic on hydrophobic surface. Initially, the droplet evaporates retaining a constant contact area. After the evaporation proceeds and minimum contact angle reached, then the three-phase contact line “slips” to a more energetically favorable position suddenly leading to a new, smaller contact radius and a larger contact angle. This cycle was repeated until the droplet dry-out. The evaporation process of nanofluid droplets on the hydrophilic surface was mainly controlled by the constant contact area evaporation mode. The “stick-slip” evaporation process was also observed on the hydrophobic surface. From the perspective of the surface energy, the “pinning” and “de-pinning” of droplet contact line was analyzed in detail. It was concluded that the wettability of the substrate and the deposition of nanoparticles affect the dynamics of the three-phase contact line on different surfaces. It is important for people to understand the droplet evaporation process in nature, industry and life.

Key words: solar energy, droplet, evaporation, nanofluid, mass transfer, wettability

中图分类号:

闫鑫, 徐进良. 太阳能加热液滴在亲疏水表面“黏-滑”蒸发[J]. 化工进展, 2019, 38(06): 2618-2625.

Xin YAN, Jinliang XU. The “stick-slip” evaporation behavior of sessile droplet with solar heating on hydrophilic and hydrophobic surfaces[J]. Chemical Industry and Engineering Progress, 2019, 38(06): 2618-2625.

图/表 9

图1 实验系统图

图2 纳米流体液滴在亲疏水表面蒸发过程

表1 实验参数不确定度

变量	不确定度
θ/(°)	±0.5
D/μm	±4.7
q _r/%	±5.0

图3 不同表面去离子水液滴接触角随时间变化

图4 不同表面纳米流体液滴接触角随时间变化

图5 不同表面液滴蒸干基底残留图案

图6 不同表面去离子水液滴接触圆直径随时间变化

图7 不同表面金纳米流体液滴接触圆直径随时间变化

图8 液滴“黏-滑”蒸发过程

参考文献 31

1	BONN D , EGGERS J , INDEKEU J , et al . Wetting and spreading[J]. Reviews of Modern Physics, 2009, 81(2): 739-805.
2	余杨, 陈秀红, 张天顺, 等 . 农药雾滴在烟叶叶面上蒸发时间的影响因素[J]. 农业工程学报, 2011, 27(11): 263-267.
	YU Y , CHEN X H , ZHANG T S , et al . Influence factors of evaporation time of pesticide droplets on different tobacco leaves[J]. Transactions of the CSAE, 2011, 27(11): 263-267.
3	TAYLOR R , COULOMBE S , OTANICAR T , et al . Small particles, big impacts: a review of the diverse applications of nanofluids[J]. Journal of Applied Physics, 2013, 113(1): 011301.
4	HU H , LARSON R G . Evaporation of a sessile droplet on a substrate[J]. J.Phys.Chem.B, 2002, 106(6): 1334-1344.
5	BIGIONI T P , LIN X M , NGUYEN T T , et al . Kinetically driven self assembly of highly ordered nanoparticle monolayers[J]. Nature Materials, 2006, 5(4): 265.
6	CHOKKALINGAM V , WEIDENHOF B , KRäMER M , et al . Optimized droplet-based microfluidics scheme for sol-gel reactions[J]. Lab on a Chip, 2010, 10(13): 1700-1705.
7	COELHO B J , VEIGAS B , ÁGUAS H , et al . A digital microfluidics platform for loop-mediated isothermal amplification detection[J]. Sensors, 2017, 17(11): 2616.
8	GORKIN R , PARK J , SIEGRIST J , et al . Centrifugal microfluidics for biomedical applications[J]. Lab on a Chip, 2010, 10(14): 1758-1773.
9	YOUNG T . An essay on the cohesion of fluids[J]. Philosophical Transactions of the Royal Society of London, 1805, 95:65-87.
10	SHANAHAN M E R . Effects of surface flaws on the wettability of solids[J]. Journal of Adhesion Science & Technology, 1992, 6(4): 489-501.
11	PICKNETT R G , BEXON R . Evaporation of sessile or pendant drops in still air[J]. Journal of Colloid & Interface Science, 1977, 61(2): 336-350.
12	BIRDI K S , VU D T . Wettability and the evaporation rates of fluids from solid surfaces[J]. Journal of Adhesion Science & Technology, 1993, 7(6): 485-493.
13	BOURGES-MONNIER C , SHANAHAN M E R . Influence of evaporation on contact angle[J]. Langmuir, 1995, 11(7): 2820-2829.
14	SHANAHAN M E R . Simple theory of “stick-slip” wetting hysteresis[J]. Langmuir, 1995, 11(3): 1041-1043.
15	段慧玲, 宣益民 . 等离激元纳米流体的光热特性研究[J]. 中国科学:技术科学, 2014, 44(8): 833-838.
	DUAN H L , XUAN Y M . Research on photo-thermal properties of plasmonic nanofluid[J]. Sci. Sin. Tech., 2014, 44(8): 833-838.
16	林璟, 方利国 . 纳米流体强化传热技术及其应用新进展[J]. 化工进展, 2008, 27(4): 488-494.
	LIN J ， FANG L G . Recent progress of technology and application of heat transfer enhancement of nanofuilds[J]. Chemical Industry and Engineering Progress, 2008, 27(4): 488-494.
17	王彩霞, 黄云, 姚华, 等 . 纳米流体研究进展[J]. 储能科学与技术, 2017, 6(1): 24-34.
	WANG C X , HUANG Y , YAO H , et al . Review of recent advances in research of nanofluids[J]. Energy Storage Science and Technology, 2017, 6(1): 24-34.
18	DEEGAN R D . Pattern formation in drying drops[J].Phys.Rev.E: Stat. Phys. Plasmas Fluids Relat Interdiscip Topics, 2000, 61(1): 475-485.
19	DEEGAN R D , BAKAJIN O , DUPONT T F , et al . Capillary flow as the cause of ring stains from dried liquid drops[J]. Nature, 1997, 389(6653): 827-829.
20	DEEGAN R D , BAKAJIN O , DUPONT T F , et al . Contact line deposits in an evaporating drop[J]. Phys. Rev. E, 2000, 62(1 Pt B): 756-765.
21	MOFFAT J R , SEFIANE K , SHANAHAN M E . Effect of TiO₂ nanoparticles on contact line stick-slip behavior of volatile drops[J]. Journal of Physical Chemistry B, 2009, 113(26): 8860.
22	LI H , FOWLER N , STRUCK C , et al . Flow triggered by instabilities at the contact line of a drop containing nanoparticles[J]. Soft Matter, 2011, 7(11): 5116-5119.
23	SEFIANE K , TADRIST L . Experimental investigation of the de-pinning phenomenon on rough surfaces of volatile drops[J]. International Communications in Heat & Mass Transfer, 2006, 33(4): 482-490.
24	GENNES P G D . Wetting: statics and dynamics[J]. Review of Modern Physics, 1985, 57(3): 827-863.
25	SHANAHAN M E , SEFIANE K , MOFFAT J R . Dependence of volatile droplet lifetime on the hydrophobicity of the substrate[J]. Langmuir the ACS Journal of Surfaces & Colloids, 2011, 27(8): 4572.
26	JIN H , LIN G , BAI L , et al . Steam generation in a nanoparticle-based solar receiver[J]. Nano Energy, 2016, 28:397-406.
27	XIE J , XU J , CHENG Y , et al . Condensation heat transfer of R245fa in tubes with and without lyophilic porous-membrane-tube insert[J]. International Journal of Heat & Mass Transfer, 2015, 88:261-275.
28	STAUBER J M , WILSON S K , DUFFY B R , et al . Evaporation of droplets on strongly hydrophobic substrates[J]. Langmuir the ACS Journal of Surfaces & Colloids, 2015, 31(12): 3653-3660.
29	ASKOUNIS A , SEFIANE K , KOUTSOS V , et al . The effect of evaporation kinetics on nanoparticle structuring within contact line deposits of volatile drops[J]. Colloids & Surfaces A: Physicochemical & Engineering Aspects, 2014, 441(3): 855-866.
30	OREJON D , SEFIANE K , SHANAHAN M E . Stick-slip of evaporating droplets: substrate hydrophobicity and nanoparticle concentration[J]. Langmuir the ACS Journal of Surfaces & Colloids, 2011, 27(21): 12834-12843.
31	SHANAHAN M E R . Kinetics of triple line motion during evaporation[J]. Contact Angle Wettability & Adhesion, 2009, 12(4): 19-31.

[1]	盛维武, 程永攀, 陈强, 李小婷, 魏嘉, 李琳鸽, 陈险峰. 微气泡和微液滴双强化脱硫反应器操作分析[J]. 化工进展, 2023, 42(S1): 142-147.
[2]	黄益平, 李婷, 郑龙云, 戚傲, 陈政霖, 史天昊, 张新宇, 郭凯, 胡猛, 倪泽雨, 刘辉, 夏苗, 主凯, 刘春江. 三级环流反应器中气液流动与传质规律[J]. 化工进展, 2023, 42(S1): 175-188.
[3]	杨寒月, 孔令真, 陈家庆, 孙欢, 宋家恺, 王思诚, 孔标. 微气泡型下向流管式气液接触器脱碳性能[J]. 化工进展, 2023, 42(S1): 197-204.
[4]	陈匡胤, 李蕊兰, 童杨, 沈建华. 质子交换膜燃料电池气体扩散层结构与设计研究进展[J]. 化工进展, 2023, 42(S1): 246-259.
[5]	邵博识, 谭宏博. 锯齿波纹板对挥发性有机物低温脱除过程强化模拟分析[J]. 化工进展, 2023, 42(S1): 84-93.
[6]	张岱凌, 丁玉梅, 左夏华, 黎昊为, 杨卫民, 阎华, 安瑛. 废弃墨粉纳米流体的光热特性[J]. 化工进展, 2023, 42(9): 4791-4798.
[7]	李洞, 王倩倩, 张亮, 李俊, 付乾, 朱恂, 廖强. 非水系纳米流体热再生液流电池串联堆性能特性[J]. 化工进展, 2023, 42(8): 4238-4246.
[8]	叶振东, 刘涵, 吕静, 张亚宁, 刘洪芝. 基于钙镁二元盐的热化学储能反应器的性能优化[J]. 化工进展, 2023, 42(8): 4307-4314.
[9]	尹新宇, 皮丕辉, 文秀芳, 钱宇. 特殊浸润性材料在防治油气管道中水合物成核与聚集的应用[J]. 化工进展, 2023, 42(8): 4076-4092.
[10]	李吉焱, 景艳菊, 邢郭宇, 刘美辰, 龙永, 朱照琪. 耐盐型太阳能驱动界面光热材料及蒸发器的研究进展[J]. 化工进展, 2023, 42(7): 3611-3622.
[11]	娄宝辉, 吴贤豪, 张驰, 陈臻, 冯向东. 纳米流体用于二氧化碳吸收分离研究进展[J]. 化工进展, 2023, 42(7): 3802-3815.
[12]	杨家添, 唐金铭, 梁恣荣, 黎胤宏, 胡华宇, 陈渊. 新型淀粉基高吸水树脂抑尘剂的制备及其应用[J]. 化工进展, 2023, 42(6): 3187-3196.
[13]	李瑞东, 黄辉, 同国虎, 王跃社. 原油精馏塔中铵盐吸湿特性及其腐蚀行为[J]. 化工进展, 2023, 42(6): 2809-2818.
[14]	章凯, 金捍宇, 刘思宇, 王帅. 鼓泡流态化气泡间相互作用下相间传质过程的模拟[J]. 化工进展, 2023, 42(6): 2828-2835.
[15]	马哲杰, 张文励, 赵炫凯, 李平. PEMFC阴极催化层氧传质阻力影响的研究进展[J]. 化工进展, 2023, 42(6): 2860-2873.