Evaporation of sessile water droplet on polydimethylsiloxane （PDMS） surfaces with three different curing ratios （5：1, 10：1, and 20：1） was experimentally investigated in this paper. We show that the constant con...Evaporation of sessile water droplet on polydimethylsiloxane （PDMS） surfaces with three different curing ratios （5：1, 10：1, and 20：1） was experimentally investigated in this paper. We show that the constant contact radius （CCR） evaporation on surface with high curing ratio lasts longer than that with low curing ratio. We also measured Young＇s moduli of PDMS films by using atomic force microscopy （AFM） and simulated surface deformation of PDMS films induced by sessile water droplet. With increasing curing ratio of PDMS film, Young＇s modulus of PDMS film is getting lower, and then there will be larger surface deformation and more elastic stored energy. Since such energy acts as a barrier to keep the three-phase contact line pinned, thus it will result in longer CCR evaporation on PDMS surface with higher curing ratio.展开更多
采用VOF(Volume of Fluid)方法捕捉两相流体的界面,利用漏电介质模型模拟静电场,数值计算并获得了静电场中单个分散液滴在另外一种不相溶黏性液体中的变形与内部流动形态。研究表明:液滴变形的方向及液滴内部循环的方向与液滴的物性参...采用VOF(Volume of Fluid)方法捕捉两相流体的界面,利用漏电介质模型模拟静电场,数值计算并获得了静电场中单个分散液滴在另外一种不相溶黏性液体中的变形与内部流动形态。研究表明:液滴变形的方向及液滴内部循环的方向与液滴的物性参数有关。液滴的变形方向与判断参数fd有关,当fd<0时,液滴沿水平横向被拉伸;当fd>0时,液滴沿垂直方向被拉伸。液滴内部流动方向与判别参数β有关,当β<1时,流动方向为从两极到赤道;当β>1时,流动方向为从赤道到两极。研究结果与前人的理论、试验及数值计算结果进行了对比分析,在变形率较小时,与试验数据、理论以及数值计算均有很好的吻合性;在较大变形率时,与试验数据与数值分析依旧有较好的吻合,与理论分析具有较大差异。展开更多
基金supported by the National Natural Science Foundation of China(11002051,11072244,and 11372313)the Key Research Program of the Chinese Academy of Sciences(KJZDEW-M01)the Instrument Developing Project of the Chinese Academy of Sciences(Y2010031)
文摘Evaporation of sessile water droplet on polydimethylsiloxane （PDMS） surfaces with three different curing ratios （5：1, 10：1, and 20：1） was experimentally investigated in this paper. We show that the constant contact radius （CCR） evaporation on surface with high curing ratio lasts longer than that with low curing ratio. We also measured Young＇s moduli of PDMS films by using atomic force microscopy （AFM） and simulated surface deformation of PDMS films induced by sessile water droplet. With increasing curing ratio of PDMS film, Young＇s modulus of PDMS film is getting lower, and then there will be larger surface deformation and more elastic stored energy. Since such energy acts as a barrier to keep the three-phase contact line pinned, thus it will result in longer CCR evaporation on PDMS surface with higher curing ratio.
文摘采用VOF(Volume of Fluid)方法捕捉两相流体的界面,利用漏电介质模型模拟静电场,数值计算并获得了静电场中单个分散液滴在另外一种不相溶黏性液体中的变形与内部流动形态。研究表明:液滴变形的方向及液滴内部循环的方向与液滴的物性参数有关。液滴的变形方向与判断参数fd有关,当fd<0时,液滴沿水平横向被拉伸;当fd>0时,液滴沿垂直方向被拉伸。液滴内部流动方向与判别参数β有关,当β<1时,流动方向为从两极到赤道;当β>1时,流动方向为从赤道到两极。研究结果与前人的理论、试验及数值计算结果进行了对比分析,在变形率较小时,与试验数据、理论以及数值计算均有很好的吻合性;在较大变形率时,与试验数据与数值分析依旧有较好的吻合,与理论分析具有较大差异。
