纳米变截面结构的导热性质

采用分子动力学方法模拟了固态氩的纳米变截面结构的导热性质,研究发现纳米变截面材料的热阻和热流的大小与方向都相关:当纳米结构沿热流的方向为渐缩时,纳米结构的热阻随热流的增加而增大,而当纳米结构沿热流的方向为渐扩时,纳米结构的热阻随热流的增加呈减小的趋势;当热流较大时,热流沿渐缩方向时的热阻明显大于热流沿渐扩方向时的热阻,但当热流较小时纳米变截面结构的热阻和热流方向的关系不大.最后依据热质的运动和传递理论的动能效应对该现象进行了分析解释.

HEAT CONDUCTION IN NANOSTRUCTURES WITH VARIABLE CROSS-SECTION

The heat conduction in the solid argon nanostructures with variable cross-section was investigated by the method of molecular dynamics simulation.We find that the thermal resistance of the nanostructures greatly depends on the magnitude and direction of heat current.With the tapered cross-section for the nanostructures along the heat flow direction,the thermal resistance increases with the increasing heat current.For the incremental section,however,the resistances of the nanostructures decrease when the heat current increases.For a higher heat current,the resistance with the heat current along the tapering direction is obviously larger than that along the incremental direction.While,for a smaller heat current,the resistance seems not depend on the direction of the heat current.The kinetic energy effect based on the thermal mass theory of heat motion and transfer is theoretically responsible for the resistance dependence on the heat current.