物理化学学报 >> 2012, Vol. 28 >> Issue (05): 1077-1084.doi: 10.3866/PKU.WHXB201202273

理论与计算化学 上一篇    下一篇

氮化硼纳米管热输运性能的分子动力学模拟

高宇飞1, 孟庆元1, 张璐2, 刘甲秋3, 荆宇航1   

  1. 1. 哈尔滨工业大学航天学院, 哈尔滨 150001;
    2. 中国医科大学, 沈阳 110001;
    3. 哈尔滨玻璃钢研究院, 哈尔滨 150001
  • 收稿日期:2011-11-30 修回日期:2012-01-28 发布日期:2012-04-26
  • 通讯作者: 荆宇航 E-mail:jingyuhang@gmail.com
  • 基金资助:

    国家自然科学基金(10772062)资助项目

Molecular Dynamics Simulation of Thermal Transport Properties for Boron Nitride Nanotubes

GAO Yu-Fei1, MENG Qing-Yuan1, ZHANG Lu2, LIU Jia-Qiu3, JING Yu-Hang1   

  1. 1. School of Astronautics, Harbin Institute of Technology, Harbin 150001, P. R. China;
    2. China Medical University, Shenyang 110001, Liaoning Province, P. R. China;
    3. Harbin FRP Research Institute, Harbin 150001, P. R. China
  • Received:2011-11-30 Revised:2012-01-28 Published:2012-04-26
  • Contact: JING Yu-Hang E-mail:jingyuhang@gmail.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (10772062).

摘要: 采用基于声子散射理论的Boltzmann-Peierls 声子传输方程(BTE)和非平衡态分子动力学模拟(NEMD)方法研究了氮化硼纳米管(BNNT)的热输运性能. 分析了BNNT的热力耦合效应, 通过BTE与NEMD两种方法相结合, 分析了温度和长度对BNNT热输运性能的影响, 并应用量子修正扩大了NEMD的研究范围. 结果表明: 随着拉伸或压缩应变的增加, BNNT热输运性能均呈降低的趋势. 通过计算声子态密度(PDOS)在理论上分析了以上结果, 发现在拉伸状态下, 声子模式的变化是决定BNNT热输运性能变化的主要因素; 在压缩状态下,热导率变化是由于模型发生明显的屈曲变形引起的. 在低温段, BNNT的热输运性能受量子效应影响最初有一个线性增加的过程, 当温度超过一定值时, 其开始显著地降低; 当BNNT长度小于120 nm时, 随着长度的增加, 其弹道性能逐渐减弱, 但仍主要体现为弹道特征, 其热导率(κ)与长度(L)基本满足κLα这一关系.

关键词: 氮化硼纳米管, 热输运性能, Boltzmann-Peierls 声子传输方程, 非平衡态分子动力学模拟, 声子态密度, 量子修正

Abstract: The Boltzmann-Peierls phonon transport equation (BTE) and non-equilibrium molecular dynamics simulation (NEMD) are used to investigate the thermal transport properties of boron nitride nanotubes (BNNTs). First, the thermal-mechanical coupling is explored using NEMD. Then, by combining BTE and NEMD, the influence of temperature and length is investigated. Quantum correction is used to extend the range over which NEMD can be used. The results demonstrate that under low-strain conditions, the thermal conductivity decreases with increasing tensile or compressive strain. Then the phonon density of state (PDOS) is used to analyze the trends in thermal transport properties theoretically; it is found that the variations in thermal transport properties under tension are caused by changes in the phonon modes, and that under compression changes are induced by the flection of the BNNT structure. The BNNT thermal conductivity increases linearly with increasing temperature because of the quantum effect at low temperatures, and it decreases significantly as the temperature reaches a certain value. When the BNNT length is less than 120 nm, the BNNT's ballistic characteristics weaken with increasing length, but it also performs ballistic characteristic mainly, and thermal conductivity (κ) and length (L) obey the relationship κLα.

Key words: Boron nitride nanotubes, Thermal transport property, Phonon Boltzmann-Peierls transport equation, Non-equilibrium molecular dynamics simulation, Phonon density of state, Quantum correction

MSC2000: 

  • O641