摘要
针对纳米流体液滴撞击固体壁面的动力学行为,建立基于相场方法描述液滴动态过程的二维数值模型,引入Kistler动态接触角模型以模拟铺展过程中液滴动态接触角变化以及三相接触线的迁移.通过模拟分析液滴铺展因子、无量纲高度的变化研究不同纳米颗粒体积分数、惯性力和液滴直径等因素对水基Al_(2)O_(3)纳米流体液滴撞击壁面的铺展回缩过程的影响机制.结果表明:超过一定体积分数的纳米颗粒使流体表现出明显的剪切稀化特性,增加液滴的黏性耗散,抑制液滴的铺展回缩过程;液滴撞击速度的增加会增大其撞击壁面时最大铺展直径和达到稳定状态的耗时,直径的增加使液滴振荡周期加长;体积分数为4%的纳米颗粒可以抑制上述两者带来的影响,使液滴更快到达稳定状态.
The dynamical behavior of nanofluid droplet impacting on the solid wall was numerically studied.A twodimensional numerical model based on the phase-field method was established,and the Kistler dynamic contact angle model was introduced to describe the evolution of droplet contact angle and three-phase contact line during spreading.The influences of nanoparticle volume fraction,inertia force and droplet diameter on the spreading and retraction behaviors of water-based Al_(2)O_(3) nanofluid droplets were studied in terms of spreading factor and dimensionless height.Results indicated that the nanoparticles with volume fraction over a certain value made the fluid exhibit obvious shear-thinning characteristics,which can increase the viscous dissipation of droplets and suppress the spreading and retraction process of droplets.The increase of droplet initial velocity would increase the maximum spreading diameter and the time to reach the stable state when it impacts on the solid surface,while the increase of droplet diameter would lengthen the oscillation period of the droplet.It is also found that the nanoparticles of 4%volume fraction can suppress the influence of increase of droplet initial velocity and diameter,and help the droplet faster to reach stable state.
作者
胡定华
刘诗雨
HU Ding-hua;LIU Shi-yu(School of Energy and Power Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2021年第5期991-998,共8页
Journal of Zhejiang University：Engineering Science
基金
国家自然科学基金青年基金资助项目(51706102)
中央高校基本科研业务费专项资金资助项目(30917011325).
关键词
纳米流体
液滴
撞击壁面
体积分数
相场方法
nanofluid
droplet
surface impingement
volume fraction
phase-field method
