摘要
纳米流体的导热系数相对于基础流体而言有了显著提高,然而这种现象却无法用现有理论进行解释。应用平衡分子动力学方法对纳米流体的导热系数进行了模拟,并研究了纳米颗粒表面类似于固体的液体吸附层的存在和特性以及其对纳米流体导热能力的影响,在此基础上进一步对纳米流体导热性能显著提高的微观机理进行了探讨。模拟结果表明由于固体分子较强的吸引力,一部分液体分子被吸附在固体颗粒表面形成一个薄层,薄层内分子的排列结构不同于纯液体的分子排列结构,导热性能也优于基础流体,从而使得纳米流体的导热系数有了显著提高。最后对纳米颗粒表面液体薄层的厚度进行了定量计算。
The thermal conductivity of nanofiuid is enhanced to a very large degree compared to the base fluid.However this thermal phenomenon can not be explained by existing theories.In this paper the thermal conductivity of the nanofluid is studied by an equilibrium molecular dynamics simulation. The property of molecular layering at liquid-solid interface and its effect on the thermal conductivity of the nanofiuid arc also investigated.By tracking the position of the nanoparticle and the liquid atoms around the spherical nanoparticle,it was found that a thin layer of liquid is formed at the interface between the nanoparticle and liquid.In the liquid layer the atoms are more crowded than in base fluid and then they will collide more frequently and transfer more energy.Consequently the thermal conductivity of the nanofiuid is enhanced.Through the analysis of the density distribution of the liquid near the nanoparticle the thickness of the layering is calculated under the parameters used in this paper.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2010年第11期1933-1936,共4页
Journal of Engineering Thermophysics
基金
国家自然基金资助项目(No.51006071)
上海市自然科学基金资助项目(No.09ZR1422400)
上海市教委科研创新资助项目(No.10ZZ91)
关键词
纳米流体
导热系数
分子动力学模拟
nanofluids
thermal conductivity
molecular dynamics simulation
