液滴碰撞倾斜壁面的动力学特性
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摘要
为了探究液滴碰撞在固体表面的动力学特性,该文进行了不同初速度的液滴以不同角度撞击光滑不锈钢表面的实验,通过实验研究了液滴的碰撞角度和Weber数对碰撞过程中液滴的动力学特性,如液滴前后沿点位移、最大铺展直径、滑移距离等的影响。结果表明:液滴的最大无量纲铺展直径随Weber数的增大而增大,随斜面倾斜角度的增大而减小;但是,液滴最终静止在表面时与表面的接触直径几乎不受Weber数和碰撞角度的影响,而是取决于液滴在表面上的前进接触角和后退接触角;另外,液滴的前后沿点位移和滑移距离随碰撞角度和Weber数的增大都呈现上升趋势。
The impact of water droplets on a smooth stainless-steel surface was studied experimentally for various velocities and angles.The experiments studied the effects of impact angle and Weber number on the dynamic characteristics of the impact process,such as the displacement of leading and trailing edges,the maximum spread diameter and gliding length.The results showed that the maximum spread diameter increased with increasing Weber number,but decreased with increasing surface slope.However,once the water droplet reached equilibrium,the droplet contact diameter was found to be independent of the impact angle and the Weber number but mainly depended on the advancing and receding contact angles of the droplet on the surface.In addition,increasing both the impact angle and the Weber number increased the gliding length.
The impact of water droplets on a smooth stainless-steel surface was studied experimentally for various velocities and angles.The experiments studied the effects of impact angle and Weber number on the dynamic characteristics of the impact process,such as the displacement of leading and trailing edges,the maximum spread diameter and gliding length.The results showed that the maximum spread diameter increased with increasing Weber number,but decreased with increasing surface slope.However,once the water droplet reached equilibrium,the droplet contact diameter was found to be independent of the impact angle and the Weber number but mainly depended on the advancing and receding contact angles of the droplet on the surface.In addition,increasing both the impact angle and the Weber number increased the gliding length.
引文
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[2]张迪,罗琦,黄伟,等.汽-水分离器内双液滴碰撞的数值模拟研究[J].核动力工程,2015,36(1):18-22.ZHANG D, LUO Q, HUANG W,et al. Numerical investigation of binary droplet collision in steam separator[J].Nuclear Power Engineering,2015,36(1):18-22.(in Chinese)
[3]杨宝海,王宏,朱恂,等.速度对液滴撞击超疏水壁面行为特性的影响[J].化工学报,2012,63(10):3027-3033.YANG B H,WANG H,ZHU X,et al.Effect of velocity on behavior of droplet impacting superhydrophobic surface[J].CIESC Journal,2012,63(10):3027-3033.(in Chinese)
[4]王磊,淮秀兰,陶毓伽,等.喷雾冷却中微液滴碰撞薄液膜的流动与换热[J].工程热物理学报, 2010,31(6):987-990.WANG L,HUAI X L,TAO Y J,et al.Flow and heat transfer of micro-droplet impact on thin liquid film during spray cooling[J].Journal of Engineering Thermophysics,2010,31(6):987-990.(in Chinese)
[5] FUKAI J,SHIIBA Y,YAMAMOTO T,et al.Wetting effects on the spreading of a liquid droplet colliding with a flat surface:Experiment and modeling[J].Physics of Fluids,1995,7(2):236-247.
[6] PASANDIDEH-FARD M,QIAO Y M,CHANDRA S,et al.Capillary effects during droplet impact on a solid surface[J].Physics of Fluids,1996,8(3):650-659.
[7]SIKALOS,MARENGO M,TROPEA C,et al.Analysis of impact of droplets on horizontal surfaces[J].Experimental Thermal and Fluid Science,2002,25(7):503-510.
[8]SIKALOS,TROPEA C,GANIC'E N.Impact of droplets onto inclined surfaces[J].Journal of Colloid and Interface Science,2005,286(2):661-669.
[9]SIKALOS,TROPEA C,GANIC'E N.Dynamic wetting angle of a spreading droplet[J].Experimental Thermal and Fluid Science,2005,29(7):795-802.
[10]HUANG Y L,WANG M J,LIAO Y C,et al.Initial wetting velocity of droplet impact and spreading:Water on glass and parafilm[J].Colloids and Surfaces A:Physicochemical and Engineering Aspects,2011,384(1-3):172-179.
[11]YEONG Y H,BURTON J,LOTH E,et al.Drop impact and rebound dynamics on an inclined superhydrophobic surface[J].Langmuir,2014,30(40):12027-12038.
[12]JIN Z Y,SUI D Y,YANG Z G.The impact,freezing,and melting processes of a water droplet on an inclined cold surface[J]. International Journal of Heat and Mass Transfer,2015,90:439-453.
[13]JIN Z Y,ZHANG H H,YANG Z G.The impact and freezing processes of a water droplet on a cold surface with different inclined angles[J].International Journal of Heat and Mass Transfer,2016,103:886-893.
[14]ANDSAGER K,BEARD K V,LAIRD N F.Laboratory measurements of axis ratios for large raindrops[J].Journal of Atmospheric Sciences,1999,56(15):2673-2683.
[15]ROUX D C D,COOPER-WHITE J J.Dynamics of water spreading on a glass surface[J].Journal of Colloid and Interface Science,2004,277(2):424-436.
[16]LIM T,HAN S,CHUNG J,et al.Experimental study on spreading and evaporation of inkjet printed pico-liter droplet on a heated substrate[J].International Journal of Heat and Mass Transfer,2009,52(1-2):431-441.
[17]CLANET C,BEGUIN C,RICHARD D,et al.Maximal deformation of an impacting drop[J].Journal of Fluid Mechanics,2004,517:199-208.
[18]YAO Y N,LI C,ZHANG H,et al.Modelling the impact,spreading and freezing of a water droplet on horizontal and inclined superhydrophobic cooled surfaces[J]. Applied Surface Science,2017,419:52-62.