Study on heat transfer and dynamics character of condensation on different hydrophobic surface

doi:10.11949/0438-1157.20250124

Abstract

Abstract:

Condensation is a common phase transition process existing in nature, which is widely used in petrochemical, nuclear power generation, refrigeration and other industrial fields, and has broad application prospects. Among them, surface droplet distribution and rapid detachment of condensate are important factors affecting the droplet condensation heat transfer efficiency. An experimental system of condensation on vertical surface was designed and the influence of contact angle and surface subcooling on condensation heat transfer performance was conducted. In addition, Cellpose algorithm was utilized which based on deep learning to analyze and quantify the size and distribution laws of droplets on the condensation surface. We found that the hydrophobic surface had the best heat transfer efficiency when the contact angle was about 120°. We summarized with a focus on analyzing the effects of droplets distribution density, droplets departure radius, and growth cycle in response to this phenomenon. The difference of cleaning area per unit time and the effect on heat transfer efficiency of droplets at different contact angles was quantitatively described.

Key words: heat transfer, condensate, surface, contact angle, droplet distribution

摘要：

凝结现象是自然界中常见的相变过程，广泛应用于石油化工、核能发电、制冷等工业领域，具有广泛的应用前景。其中，表面液滴分布与冷凝液快速脱离是影响滴状冷凝传热效率的重要因素。本研究搭建了竖直壁面蒸汽凝结传热实验平台，在不同接触角表面、不同过冷度条件下进行蒸汽凝结传热实验，重点考察了蒸汽在不同接触角疏水表面的滴状凝结特性，并利用基于深度学习的Cellpose算法统计冷凝表面上液滴的尺寸与分布规律。实验发现表面接触角在120°左右时具有最优异的传热性能。针对该现象，重点分析了表面液滴分布密度、液滴脱离半径与生命周期对冷凝传热效率的影响，定量描述了不同接触角表面液滴在单位时间内清扫面积的差异及对传热效率的影响。

关键词: 传热, 凝结, 表面, 接触角, 液滴尺寸分布

CLC Number:

TK 124

Luyuan GONG, Zhenglong GUO, Denghui ZHAO, Yali GUO, Jian ZHOU, Qianqian HAN, Shengqiang SHEN. Study on heat transfer and dynamics character of condensation on different hydrophobic surface[J]. CIESC Journal, 2025, 76(8): 3932-3943.

龚路远, 果正龙, 赵登辉, 郭亚丽, 周健, 韩倩倩, 沈胜强. 不同疏水性表面冷凝传热性能及动力学特征研究[J]. 化工学报, 2025, 76(8): 3932-3943.

Figures/Tables 15

Fig.1 Preparation process of hydrophobic surface

Table 1 Processing parameters for hydrophobic surface preparation

目标接触角/(°)	激光线间距/mm	激光功率/%	激光频率/kHz	十八烷基硫醇浓度/(mol·L^-1)	最大接触角/(°)	最小接触角/(°)	实际接触角/(°)	误差/%
110	—	—	—	0.0025	113.690	110.645	112.349	2.135
120	—	—	—	0.0025	121.224	118.340	120.480	0.400
130	0.04	30	300	0.0025	133.617	130.759	131.902	1.463
140	0.04	40	250	0.0025	142.424	139.881	141.172	0.837
150	0.04	70	150	0.0025	150.384	148.008	149.214	-0.524
160	0.005	60	90	0.05	159.307	156.913	158.452	-0.968

Fig.2 Experimental set-up of steam condensation and the structure of the condensing chamber

Fig.3 Steam condensation process on hydrophobic surface and processed image (θ=149°, ΔT=8 K)

Fig.4 Comparison of experimental results and calculated of steam condensation in filmwise condensation on vertical surface

Table 2 Result of the error analysis for the experiment

接触角/(°)	误差/%
接触角/(°)	热通量	传热系数
112	5.042	11.072
120	4.725	11.954
132	5.236	10.910
141	5.877	10.718
149	6.501	10.772
158	7.329	11.093

Fig.5 Effect of surface subcooling on heat transfer and coefficient in condensation

Fig.6 Droplet condensation images on hydrophobic surface at different contact angles (ΔT=8 K)

Fig. 7 Distribution density of droplets on surface with different contact angles

Fig.8 Heat transfer of different droplet radius on hydrophobic surfaces with different contact angle

Fig.9 Effect of surface contact angle and subcooling on droplet departure size

Fig.10 Different modes of droplet combination (θ =158°，ΔT =8 K)

Fig.11 Effect of surface contact angle and subcooling on droplet growth cycle

Fig.12 Image and binarized boundary after droplet cleaning

Fig.13 Effect of surface contact angle and subcooling on droplet cleaning area rate

References 36

[1]	Yang H, Xu C, Yang B, et al. Performance analysis of an organic Rankine cycle system using evaporative condenser for sewage heat recovery in the petrochemical industry[J]. Energy Conversion and Management, 2020, 205: 112402.
[2]	周莉, 高利民, 祝晓亮, 等. 石化高温凝结水除盐技术实验研究[J]. 水处理技术, 2015, 41(3): 96-98, 102.
	Zhou L, Gao L M, Zhu X L . et al. Desalination of petrochemical high-temperature condensate[J]. Technology of Water Treatment, 2015, 41(3): 96-98, 102.
[3]	郝毅. 核电机组中蒸汽凝结引发的水锤事件分析与处理[J]. 电工技术, 2024(9): 191-194.
	Hao Y. Analysis and treatment of water hammer events caused by steam condensation in nuclear power units[J]. Electric Engineering, 2024(9): 191-194.
[4]	王中新, 王建国. 核电汽轮机组凝汽器传热性能劣化影响分析[J]. 内蒙古科技与经济, 2024(19): 119-122, 127.
	Wang Z X, Wang J G. Analysis on the influence of heat transfer performance deterioration of condenser of nuclear power turbine unit[J]. Inner Mongolia Science Technology & Economy, 2024(19): 119-122, 127.
[5]	Mohammed I M, Kumar R. Experimental evaluation of condensation of R32 and R134a over a plain tube[J]. Heat Transfer Engineering, 2025, 46(3): 252-267.
[6]	孙晨, 欧阳新萍, 夏荣鑫. R1234ze(E)与R134a在水平双侧强化管外的凝结换热对比实验[J]. 热能动力工程, 2021, 36(8): 72-77.
	Sun C, Ouyang X P, Xia R X. Experimental comparison on condensation heat transfer of R1234ze(E) and R134a on horizontal double-sided strengthened tube[J]. Journal of Engineering for Thermal Energy and Power, 2021, 36(8): 72-77.
[7]	唐桂华, 胡浩威, 牛东, 等. 蒸汽珠状冷凝传热的研究进展[J]. 科学通报, 2020, 65(17): 1653-1676.
	Tang G H, Hu H W, Niu D, et al. Advances in vapor dropwise condensation heat transfer[J]. Chinese Science Bulletin, 2020, 65(17): 1653-1676.
[8]	El Fil B, Kini G, Garimella S. A review of dropwise condensation: theory, modeling, experiments, and applications[J]. International Journal of Heat and Mass Transfer, 2020, 160: 120172.
[9]	彭本利. 液滴动态特性调控强化冷凝传热的研究和LB模拟[D]. 大连: 大连理工大学, 2014.
	Peng B L. Study and LB simulation of condensation heat transfer enhancement by adjusting dynamic characteristics of droplets[D]. Dalian: Dalian University of Technology, 2014.
[10]	Gose E E, Mucciardi A N, Baer E. Model for dropwise condensation on randomly distributed sites[J]. International Journal of Heat and Mass Transfer, 1967, 10(1): 15-22.
[11]	Rose J W, Glicksman L R. Dropwise condensation: the distribution of drop sizes[J]. International Journal of Heat and Mass Transfer, 1973, 16(2): 411-425.
[12]	Lan Z, Ma X H, Zhou X D, et al. Theoretical study of dropwise condensation heat transfer: effect of the liquid-solid surface free energy difference[J]. Journal of Enhanced Heat Transfer, 2009, 16(1): 61-71.
[13]	兰忠, 马学虎, 张宇, 等. 引入液固界面效应的滴状冷凝传热模型[J]. 化工学报, 2005, 56(9): 1626-1632.
	Lan Z, Ma X H, Zhang Y, et al. Dropwise condensation heat transfer model with liquid-solid surface free energy difference effect[J]. Journal of Chemical Industry and Engineering(China), 2005, 56(9): 1626-1632.
[14]	Kim S, Kim K J. Dropwise condensation modeling suitable for superhydrophobic surfaces[J]. Journal of Heat Transfer, 2011, 133(8): 081502.
[15]	Lee S, Yoon H K, Kim K J, et al. A dropwise condensation model using a nano-scale, pin structured surface[J]. International Journal of Heat and Mass Transfer, 2013, 60: 664-671.
[16]	Miljkovic N, Enright R, Wang E N. Modeling and optimization of superhydrophobic condensation[J]. Journal of Heat Transfer, 2013, 135(11): 111004.
[17]	Maeda Y, Lv F Y, Zhang P, et al. Condensate droplet size distribution and heat transfer on hierarchical slippery lubricant infused porous surfaces[J]. Applied Thermal Engineering, 2020, 176: 115386.
[18]	赵崇岩, 陈凤, 闫贺, 等. 超疏水表面弹跳凝结液滴尺寸分布模拟[J]. 工程热物理学报, 2020, 41(11): 2782-2787.
	Zhao C Y, Chen F, Yan H, et al. Numerical simulation of droplet size distribution for jumping condensation on the superhydrophobic surface[J]. Journal of Engineering Thermophysics, 2020, 41(11): 2782-2787.
[19]	赵崇岩, 颜笑, 黄志勇, 等. 滴状凝结全过程液滴尺寸分布数值模拟[J]. 工程热物理学报, 2020, 41(6): 1485-1490.
	Zhao C Y, Yan X, Huang Z Y, et al. Numerical simulation of droplet size distribution in the whole process of dropwise condensation[J]. Journal of Engineering Thermophysics, 2020, 41(6): 1485-1490.
[20]	Suh Y, Lee J, Simadiris P, et al. A deep learning perspective on dropwise condensation[J]. Advanced Science, 2021, 8(22): 2101794.
[21]	Huang T E, Lu Y S, Wei Z Z, et al. Ultrahigh subcooling dropwise condensation heat transfer on slippery liquid-like monolayer grafted surfaces[J]. ACS Applied Materials & Interfaces, 2024, 16(39): 53285-53298.
[22]	温荣福. 低压蒸汽滴状冷凝传热微观机理及强化[D]. 大连: 大连理工大学, 2015.
	Wen R F. Micro-mechanism and strengthening of heat transfer in low pressure steam dropwise condensation[D]. Dalian: Dalian University of Technology, 2015.
[23]	马学虎, 汪明哲, 兰忠, 等. 表面纳米结构及其自由能对滴状冷凝传热的影响[J]. 工程热物理学报, 2009, 30(10): 1752-1754.
	Ma X H, Wang M Z, Lan Z, et al. Effect of surface nanostructure and surface free energy on dropwise condensation heat transfer[J]. Journal of Engineering Thermophysics, 2009, 30(10): 1752-1754.
[24]	梅茂飞, 胡峰, 韩崇, 等. 滴状冷凝过程中液滴接触角对热流密度的影响[J]. 徐州工程学院学报(自然科学版), 2017, 32(4): 50-54.
	Mei M F, Hu F, Han C, et al. Influence of contact angle on heat flux in dropwise condensation[J]. Journal of Xuzhou Institute of Technology (Natural Sciences Edition), 2017, 32(4): 50-54.
[25]	Pachitariu M, Stringer C. Cellpose 2.0: how to train your own model[J]. Nature Methods, 2022, 19(12): 1634-1641.
[26]	Stringer C, Wang T, Michaelos M, et al. Cellpose: a generalist algorithm for cellular segmentation[J]. Nature Methods, 2021, 18(1): 100-106.
[27]	陈逢军, 郝姗媚, 黄帅, 等. 基于静电喷雾法制备油水分离的超疏水表面研究[J]. 表面技术, 2020, 49(10): 152-160.
	Chen F J, Hao S M, Huang S, et al. Preparation of superhydrophobic surface for oil-water separation based on electrostatic spray method[J]. Surface Technology, 2020, 49(10): 152-160.
[28]	温荣福, 兰忠, 彭本利, 等. 蒸汽滴状冷凝液滴表面温度分布及演化[J]. 工程热物理学报, 2014, 35(8): 1624-1628.
	Wen R F, Lan Z, Peng B L, et al. Distribution and evolution of droplet surface temperature field during dropwise condensation[J]. Journal of Engineering Thermophysics, 2014, 35(8): 1624-1628.
[29]	潘瑞, 钟敏霖. 超快激光制备超疏水超亲水表面及超疏水表面机械耐久性[J]. 科学通报, 2019, 64(12): 1268-1289.
	Pan R, Zhong M L. Fabrication of superwetting surfaces by ultrafast lasers and mechanical durability of superhydrophobic surfaces[J]. Chinese Science Bulletin, 2019, 64(12): 1268-1289.
[30]	Zhao D H, Guo Y L, Guo Z L, et al. Mechanistic analysis of droplets blocked at junctions of serial wedge pattern[J]. Physics of Fluids, 2024, 36(9): 092103.
[31]	Tran N G, Chun D M. Green manufacturing of extreme wettability contrast surfaces with superhydrophilic and superhydrophobic patterns on aluminum[J]. Journal of Materials Processing Technology, 2021, 297: 117245.
[32]	王梅玲, 王海, 任丹华, 等. JJF 2099—2024《光学接触角测量仪校准规范》解读[J]. 中国计量, 2024(11): 32-34.
	Wang M L, Wang H, Ren D H, et al. Interpretation of JJF 2099—2024 Calibration Specification for Optical Contact Angle Measuring Instrument [J]. China Metrology, 2024(11): 32-34.
[33]	刘维龙, 刘文芳, 高心悦, 等. 基于螺线拟合的高精度接触角测量方法[J]. 科学技术与工程, 2023, 23(2): 699-706.
	Liu W L, Liu W F, Gao X Y, et al. High precision contact angle measurement method based on spiral sitting[J]. Science Technology and Engineering, 2023, 23(2): 699-706.
[34]	李雯, 兰忠, 强伟丽, 等. 蒸汽冷凝近壁过渡区团簇演化特性[J]. 化工学报, 2022, 73(7): 2865-2873.
	Li W, Lan Z, Qiang W L, et al. Evolution characteristics of clusters in transitional region near subcooled wall during condensation process of steam[J]. CIESC Journal, 2022, 73(7): 2865-2873.
[35]	贺征宇, 彭本利, 苏风民, 等. 微纳结构超疏水表面参数影响含不凝气蒸汽冷凝传热的理论分析[J]. 化工学报, 2021, 72(5): 2570-2577.
	He Z Y, Peng B L, Su F M, et al. Theoretical analysis on the effect of micro-nano structured superhydrophobic surface parameters on dropwise condensation with non-condensable gas[J]. CIESC Journal, 2021, 72(5): 2570-2577.
[36]	O'Neill G A, Westwater J W. Dropwise condensation of steam on electroplated silver surfaces[J]. International Journal of Heat and Mass Transfer, 1984, 27(9): 1539-1549.