冷凝结霜是能源动力、航空航海、制冷低温等领域的共性基础难题，加深对固体表面复杂冷凝和结霜/融霜现象的科学认知，具有长远的科学和工程意义。本书介绍了超疏水表面特殊的冷凝液滴行为特征，报道了冷凝液滴的自推进扫掠行为，阐明了液滴扫掠和液滴弹跳对液滴群生长的影响规律。通过对超疏水表面融化液滴的自发运动进行细致探索，明确了超疏水表面融霜液膜的演化规律，定义了表征固体表面接触角滞后相对于静态接触角重要程度的无量纲数，为相关工程应用提供了指导。 本书可供动力工程及工程热物理、化学工程与技术、力学等专业的高年级本科生、研究生，以及工程技术和科研人员参考。

1 Introduction 1 1.1 Research Background and Proposal of Topics 1 1.1.1 Condensation 1 1.1.2 Frosting and Icing 2 1.1.3 Proposal of Topics 3 1.2 Research Status 4 1.2.1 Fabrication of Superhydrophobic Surfaces 5 1.2.2 Condensation and Droplet Behaviors on Superhydrophobic Surfaces 8 1.2.3 Frost/Ice Melting and Droplet Behaviors on Superhydrophobic Surfaces 15 1.2.4 Summary of Research Status 17 1.3 Research Contents of Present Work 18 References 19 2 Experimental System and Superhydrophobic Surfaces 27 2.1 Experimental System and Data Processing 27 2.1.1 Overview of Experimental System 27 2.1.2 Data Processing Methods 30 2.2 Fabrication and Characterization of Superhydrophobic Surfaces . 31 2.2.1 Fabrication Methods of Superhydrophobic Surfaces 31 2.2.2 Al-Based Superhydrophobic Surfaces 32 2.2.3 Cu-Based Superhydrophobic Surfaces 36 2.3 Selection of Superhydrophobic Surfaces for Experiments 39 2.4 Summary 40 References . 41 3 Behaviors of Condensed Droplets on Superhydrophobic Surfaces . 43 3.1 Experimental Surfaces and Conditions . 43 3.2 Condensed Droplet Behaviors on Superhydrophobic Surfaces 44 3.2.1 Immobile Droplet Coalescence . 44 XVI Contents 3.2.2 Self-propelled Droplet Jumping 45 3.2.3 Self-propelled Droplet Sweeping 46 3.3 Statistics of Condensed Droplet Behaviors on Superhydrophobic Surfaces 49 3.4 Critical Conditions for Self-propelled Droplet Behaviors 51 3.4.1 Theoretical Model 52 3.4.2 Minimum Critical Droplet Radius 54 3.4.3 Critical Ratio of Droplet Radius 56 3.4.4 Critical Static Contact Angle 57 3.5 Effect of Self-propelled Droplet Behaviors on Droplet Growth . 58 3.5.1 Droplet Diameter Distribution 58 3.5.2 Average Droplet Diameter 61 3.5.3 Surface Coverage Fractions 62 3.5.4 Effects of Working Conditions 63 3.6 Summary 64 References 65 4 Numerical Simulations of Multi-droplet Coalescence-Induced Jumping 67 4.1 Simulation Objects and Conditions 68 4.2 Mathematical Model 69 4.2.1 Control Equation 69 4.2.2 Computational Domain, Boundary Conditions, and Grids 71 4.2.3 Energy Analysis 72 4.3 Model Validation—Two-Droplet Coalescence-Induced Jumping . 73 4.4 Multi-droplet Coalescence-Induced Droplet Jumping 76 4.4.1 Effect of Coalesced Droplet Number 76 4.4.2 Effect of Droplet Position Distribution 81 4.5 Summary 87 References 87 5 Dynamic Melting of Freezing Droplets on Superhydrophobic Surfaces 89 5.1 Experimental Surfaces and Conditions 89 5.2 Freezing of Condensed Droplets on Superhydrophobic Surfaces . 91 5.3 Self-propelled Behaviors During Melting Process of Freezing Droplets 94 5.3.1 Melting Droplet Rotating 94 5.3.2 Melting Droplet Jumping 96 5.3.3 Melting Droplet Sliding 97 5.4 Effects of Self-propelled Melting Droplet Behaviors on Surface Coverage Fraction 99 5.5 Summary of This Chapter 101 References 102 Contents XVII 6 Meltwater Evolution During Defrosting on Superhydrophobic Surfaces 105 6.1 Experimental Surfaces and Conditions 105 6.2 Meltwater Evolution on Superhydrophobic Surfaces 107 6.3 Edge Curling Phenomenon of Meltwater Films 109 6.4 Non-breaking Phenomenon of Chained Droplets 110 6.5 Summary 113 References 114 7 Relation Between Surface Wettability and Droplet Behaviors, and Hysteresis Number 117 7.1 Morphologies and Behaviors of Condensed Droplets and Melted Droplets 117 7.1.1 Morphologies and Behaviors of Condensed Droplets 117 7.1.2 Morphologies and Behaviors of Melted Droplets 120 7.2 Relation Between Surface Wettability and Droplet Behaviors 122 7.3 Hysteresis Number 126 7.4 Summary 129 References 130 8 Conclusions and Outlooks 133 8.1 Main Conclusions in the Present Work 133 8.2 Innovations in the Present Work 136 8.3 Outlooks for Future Research 137