接触角滞后对组合表面液滴运动的影响  

Effect of Contact Angle Hysteresis on Droplet Dynamic Behaviors for Hybrid Surface

作　　者：马学虎[1] 杜宾港 胡少波[1] 陈彦松 兰忠[1] 郝婷婷[1] 

机构地区：[1]大连理工大学化学工程研究所辽宁省化工资源清洁利用重点实验室,大连116024

出　　处：《工程热物理学报》2017年第4期855-861,共7页Journal of Engineering Thermophysics

基　　金：国家自然科学基金重点项目(No.51236002);国家自然科学基金项目(No.51476018)

摘　　要：本文通过控制NaOH和(NH_4)_2S_2O_8溶液的刻蚀时间,制备了具有不同接触角滞后超疏水区的0.5 mm-0.5mm超疏水疏水组合表面,可视化研究了常压纯蒸汽下液滴脱落半径,冲刷周期,尺寸分布.电镜表征结果表明,刻蚀时间越长,所制备超疏水表面的微纳结构越细,导致液滴接触角滞后增加。在0.5 mm-0.5 mm超疏水-疏水组合表面冷凝过程中,存在两种排液行为:液滴横向抽吸和液滴跨区脱落。随着超疏水区接触角滞后的增加,对液滴的抽吸作用越强。液滴跨区脱落直径随着超疏水区接触角滞后的增加有减小趋势,表面冲刷周期随超疏水区接触角滞后的增加而减小;与完全疏水表面相比,组合表面疏水区域液滴尺寸较小,主要集中在50μm以内。Superhydrophobic-hydrophobic hybrid surface with different Contact Angle Hysteresis（CAH） in superhydrophobic region are prepared by controlling the etching time of NaOH and（NH4）2S2O8 mixed solution.Departure droplet diameters,sweeping period and drop size distribution of different surfaces are researched through experiments in this paper.Environmental Scanning electron microscopy（ESEM）results show that micro-nano structures of superhydrophobic surface become finer with the increase of etching time,which lead to the increase of CAH of the superhydrophobic surface.Two kinds of droplets drainage behaviors are observed in the condensation experiment：droplets suction horizontally and trans-regional droplets shedding.Superhydrophobic surface with larger CAH is more capable to aggregate the droplets on hydrophobic region thus enhance the renewal of condensation surface and heat transfer performance.Departure droplet diameters of trans-regional droplets decrease with the increase of CAH of the superhydrophobic region and the sweeping period has the same tendency.Compared with completely hydrophobic surface,droplets radius on hydrophobic region of hybrid surface are smaller,which are mainly distributed in 0-50 urn range.

关 键 词：接触角滞后 滴状冷凝 组合表面 抽吸作用 

分 类 号：TK124[动力工程及工程热物理—工程热物理]