摘要
建立以水分子为基础液、中空SiO_(2)纳米颗粒为悬浮粒子的纳米流体模型,采用分子动力学模拟方法研究中空SiO_(2)纳米颗粒在水中的运动特性.结果表明,纳米颗粒在水中首先进行无规则运动,随后相互靠近、黏结,最后达到相对平衡.水分子的加入可以延缓纳米颗粒的团聚,但不足以形成稳定的纳米流体.纳米流体中纳米颗粒间相互作用能为-632kJ/mol,表现为相互吸引,纯纳米颗粒和纳米流体中的纳米颗粒一旦发生聚集,将无法自行分散.纳米流体中距离纳米颗粒表面较近的水分子扩散系数接近于零;距离纳米颗粒表面越远,水分子扩散系数越大,直至2.43×10^(-9)m^(2)/s.这意味着纳米颗粒在运动初期靠近速度较快,随纳米颗粒间距离的缩短其靠近速度变慢.
A model of nanofluids with water molecules as the base fluid and hollow silica nanoparticles as suspended particles was established,and the motion characteristics of the hollow silica nanoparticles in water were studied by molecular dynamics(MD)simulation.Results show that the nanoparticles first move irregularly in water,then approach and adhere to each other,and finally reach a relative balance.The addition of water molecules can delay the aggregation of nanoparticles,but not enough to form stable nanofluids.The interaction energy between nanoparticles in the nanofluid is-632 kJ/mol,showing mutual attraction.Once the aggregation of the pure nanoparticles or the nanoparticles in nanofluid occurs,they cannot disperse spontaneously.The diffusion coefficient of the water molecules near the surface of nanoparticles in nanofluids is close to zero.The further the distance from the surface of nanoparticles,the greater the diffusion coefficient of the water molecules,up to 2.43×10^(-9)m^(2)/s.It means that the approaching speed of nanoparticles is faster at the beginning of motion,and the approaching speed becomes slower with the decrease of the distance between nanoparticles.
作者
生丽莎
陈振乾
Sheng Lisha;Chen Zhenqian(School of Energy and Environment,Southeast University,Nanjing 210096,China;Jiangsu Province Key Laboratory of Solar Energy Science and Technology,Southeast University,Nanjing 210096,China)
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2021年第4期700-706,共7页
Journal of Southeast University：Natural Science Edition
基金
国家自然科学基金资助项目(51676037).
