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采用基于线性响应理论的非平衡分子动力学模拟方法,通过3体Tersoff势函数描述原子间的相互作用,模拟了C,BN和SiC纳米管的热传导过程.研究了轴向长度、温度和外加拉伸应变等因素对3种纳米管的轴向热导率的影响,并对3种纳米管的导热性能进行了比较.结果表明:纳米管的热导率k随着轴向长度L的增加而增加,两者大致呈k∝L~α关系,与求解声子传输方程得到的理论解一致;纳米管的热导率随温度升高而降低;随着轴向拉伸应变的增大,纳米管的热导率有先增加后降低的转变趋势,但3种纳米管的热导率发生转变时对应的拉伸应变不同;相同条件下3种纳米管的热导率从大到小依次为:C,BN和SiC.
Using the non-equilibrium molecular dynamics simulation method based on the linear response theory, the thermal conduction process of C, BN and SiC nanotubes was simulated by the Tersoff potential function of the three-body model. The effects of axial length, temperature, Tensile strain and other factors on the axial thermal conductivity of the three kinds of nanotubes and the thermal conductivity of the three kinds of nanotubes were compared.The results show that the thermal conductivity k of the nanotubes increases with the increase of the axial length L Increase, the two are roughly the relationship kαL ~ α, which is consistent with the theoretical solution of solving the phonon transport equation; the thermal conductivity of the nanotube decreases with increasing temperature; as the axial tensile strain increases, The thermal conductivity of the tube first increases and then decreases, but the corresponding tensile strain varies with the thermal conductivity of the three kinds of nanotubes. The thermal conductivity of the three kinds of nanotubes under the same conditions is : C, BN and SiC.