Article
Chemistry, Multidisciplinary
Jie Tan, Yufeng Guo, Wanlin Guo
Summary: The spreading of water nanodroplets on solid surfaces after impinging has been systematically studied using large-scale molecular dynamics simulations. It was found that the spreading rates of nanodroplets initially increase and then decrease with increasing diameter, with the highest spreading rates observed at diameters of 17-19 nm. This is due to the combined effect of the strongest interfacial and surface interactions within water molecules. The results also revealed the nonmonotonic characteristics of spreading velocity, interface work of adhesion, and surface tension with nanodroplet diameter.
Article
Thermodynamics
Fengchao Li, Ying Hu, Yu Fu, Guangtao Li, Ronggang Wei, Chao Li, Chunbo Hu
Summary: An experimental system was designed to investigate the impact process of molten Al droplets on the walls of a combustion chamber. Empirical correlations for the residence time and spreading diameter of the droplets were established, and a theoretical model was developed to analyze the energy distribution during the collision. The results provide a theoretical basis for the design of thermal protection systems for solid rocket motors.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Bin Li, Abbasali Abouei Mehrizi, Shiji Lin, Sangwoo Joo, Longquan Chen
Summary: The impact dynamics of viscoelastic droplets on a superhydrophobic surface beyond the boiling temperature was studied, with findings suggesting that surface temperature and polymer concentration have varying effects on droplet behavior. Additionally, temperature increase or polymer concentration decrease can accelerate droplet retraction speed.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Chemistry, Multidisciplinary
Zhanglei Zhu, Youhua Jiang, Donghui Wang, Wanzhong Yin, Jaroslaw W. Drelich
Summary: The study examined the maximum adhesion characteristics of liquid droplets on curved surfaces, revealing that the contact angle is consistent along the droplet perimeter and the droplet base is nonaxisymmetric.
Article
Multidisciplinary Sciences
Yukihiro Yonemoto, Kanta Tashiro, Kazuki Shimizu, Tomoaki Kunugi
Summary: The impingement behaviors and splashing phenomena of droplets on solid substrates are investigated in this study. The prediction of droplet splashing is based on the pressure balance and energy balance equations. The driving forces for droplet spreading are hydrodynamic and hydrostatic pressures, while the opposing forces are capillary pressure and viscous stress. The occurrence of splashing depends on whether the driving forces overcome the opposing forces, and is affected by surface factors such as wettability and roughness.
SCIENTIFIC REPORTS
(2022)
Article
Engineering, Mechanical
Lei Xia, Faze Chen, Teng Liu, Du Zhang, Yanling Tian, Dawei Zhang
Summary: This study reveals the critical role of air in the impingement of droplets on superhydrophobic surfaces through simulations and experiments. The results show a non-monotonic variation of the non-dimensional maximum wetting diameter with increasing Ohnesorge number, and a non-monotonic variation of the dimensionless viscous extension with increasing impact number. Additionally, the non-dimensional contact time of bouncing droplets decreases rapidly with increasing Weber number.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Chemistry, Physical
Jinming Zhang, Wei Ding, Uwe Hampel
Summary: This study deconstructs a complex surface defect into three primary surface defects and uses large-scale Molecular Dynamics simulations to investigate the mechanisms of droplet-solid static friction forces induced by these defects. Three element-wise static friction forces related to the primary surface defects are revealed, and it is found that the static friction force induced by chemical heterogeneity is contact line length dependent while the static friction force induced by atomic structure and topographical defect is contact area dependent. The latter causes energy dissipation and leads to a wiggle movement of the droplet during the static-kinetic friction transition.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Physics, Applied
Kaixuan Zhang, Jie Li, Yulei Wang, Chensen Lin, Jiayi Zhao, Yang Liu, Shuo Chen
Summary: Anti-icing is a critical issue for solid surfaces in various industries and has gained significant attention in recent years. Traditional methods for anti-icing on solid surfaces often require a significant amount of energy. This study provides an overview of the potential applications and recent advancements in anti-icing, as well as introduces a novel method of designing superhydrophobic anti-icing surfaces based on droplet dynamics. Furthermore, it explores several related topics that could contribute to future research, such as the design of solid surfaces with bio-inspired properties.
MODERN PHYSICS LETTERS B
(2023)
Article
Chemistry, Multidisciplinary
Ling Pan, Yunhui Chen, Zhi Li, Xuqing Xie
Summary: This work investigates the dynamical behavior and wetting condition of droplets captured by different surfaces in electric fields through molecular dynamics simulations. The results show that droplets exhibit electric stretching effect when striking solid surfaces in electric fields, and the stretch length of droplets increases with the enhancement of electric field intensity. The direction of electric fields has an effect on the stretch length in the low field strength regime but makes no difference in the high field strength regime.
Article
Chemistry, Physical
Zhifeng Hu, Xuan Zhang, Sihang Gao, Zhiping Yuan, Yukai Lin, Fuqiang Chu, Xiaomin Wu
Summary: This study reveals the spreading dynamics of droplets on ridged superhydrophobic surfaces through experiments, numerical simulations, and theoretical analysis. It shows significant asymmetry in the spreading and retraction dynamics in the axial and spanwise directions, as well as the existence of a critical size ratio affecting the maximum axial spreading coefficient. The maximum axial spreading coefficient can be reduced by 25-40% at the critical size ratio compared with that on flat surfaces.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Jiayu Du, Xiong Wang, Yanzhi Li, Qi Min, Xinxin Wu
Summary: Based on the energy conservation approach, a universal model has been developed to predict the maximum spreading factor of liquid droplet impact on a smooth solid surface. Through simulations and experiments, the model effectively reduces computing errors and overcomes limitations of previous models in the viscous regime. It is shown that previous models underestimated the maximum spreading factor due to an overestimation of viscous dissipation. By improving the formulation to compute viscous dissipation, the model has shown good performance in the capillary regime as well.
Article
Nanoscience & Nanotechnology
Jack Dawson, Samual Coaster, Rui Han, Johannes Gausden, Hongzhong Liu, Glen McHale, Jinju Chen
Summary: This study investigates the dynamics of droplets impacting three hydrophobic slippery surfaces and finds that the impact regime strongly depends on the surface properties. The findings provide insights for selecting surface properties to achieve desirable droplet impact characteristics.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Mechanics
Zhicheng Yuan, Mitsuhiro Matsumoto, Ryoichi Kurose
Summary: This study numerically investigated the directional rebound behavior of water droplets on surfaces with wettability gradients. The results show that the rebound behavior of droplets is influenced by a combination of wettability gradient, Weber number, groove width, and groove depth. This research provides important insights for designing wettability gradient surfaces to control droplet transport.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2021)
Article
Thermodynamics
Yifu Shu, Zhifeng Hu, Yanhui Feng, Xiaomin Wu, Zhichao Dong, Fuqiang Chu
Summary: Superhydrophobic surfaces have great potential in practical applications. This study investigates the hydrodynamics of droplet impacting on high-speed moving superhydrophobic surfaces through experiments and analysis. The findings provide important insights for engineering applications.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Physics, Multidisciplinary
Jianqiang Hou, Jianying Gong, Xin Wu
Summary: We numerically study the freezing process of impinging water droplets on inclined cold superhydrophobic surfaces, focusing on the dynamic and heat transfer properties. We find that increasing the surface inclination angle and decreasing the contact angle hysteresis can promote the rebound of impinging water droplets at higher cold temperatures. The influence of the cold surface temperature is stronger on the receding side of the droplets, and the frozen region appears first on this side.
Article
Chemistry, Multidisciplinary
Tushar Srivastava, Santosh Kumar Jena, Sasidhar Kondaraju
Summary: This research investigates the dynamics of droplet spreading on inclined surfaces, identifying three phases: inertia-dominated phase 1, asymmetry in radial evolution in phase 2, and lateral retraction while longitudinal expansion in phase 3.Results show that inertia controls longitudinal spread in phases 1 and 2, while gravity forces dominate in phase 3, with the experimental and model results showing good agreement.
