CAJ | 학술논문

采用分子动力学方法模拟融化-淬火工艺制备非晶态 SiO2材料和 SiO2气凝胶初级粒子单元。基于非平衡分子动力学(Non-equilibrium molecular dynamics，NEMD)理论计算体态材料和初级粒子单元的导热系数，计算过程考虑了冷热源引起的尺度效应。结果表明，计算得到的体态材料导热系数与文献计算结果吻合良好。对于初级粒子单元，在粒径2～6 nm范围内，粒子直径使得粒子单元导热系数出现了尺度效应，但是影响相对较小。粒子间界面直径对粒子单元导热系数影响很大，当粒子直径为3 nm时，界面直径从0.89 nm增加到2.49 nm，粒子单元导热系数增大了171.61%，粒子界面处的温度阶跃，表明存在明显的界面热阻效应；且界面直径越小，界面热阻越大。
채용분자동역학방법모의융화-쉬화공예제비비정태 SiO2재료화 SiO2기응효초급입자단원。기우비평형분자동역학(Non-equilibrium molecular dynamics，NEMD)이론계산체태재료화초급입자단원적도열계수，계산과정고필료랭열원인기적척도효응。결과표명，계산득도적체태재료도열계수여문헌계산결과문합량호。대우초급입자단원，재립경2～6 nm범위내，입자직경사득입자단원도열계수출현료척도효응，단시영향상대교소。입자간계면직경대입자단원도열계수영향흔대，당입자직경위3 nm시，계면직경종0.89 nm증가도2.49 nm，입자단원도열계수증대료171.61%，입자계면처적온도계약，표명존재명현적계면열조효응；차계면직경월소，계면열조월대。
The amorphous SiO2 and primary particle unit(PPU) of SiO2 aerogel are generated using the melting-quenching process based on the molecular dynamics method. Their thermal conductivities(TC) are also calculated by the non-equilibrium molecular dynamics(NEMD). The size effect on the TC caused by the heat source and heat sink has been taken into account. The predicted TC of the bulk amorphous SiO2 material is in good agreement with the available results in literature. Calculated results also show that the particle diameter has made the TC of the PPU show scale effect in the range of 2-6 nm though the effect is relative small. The diameter of the interface between particles has significant effect on the TC of the PPU which increase 171.61% as the interface diameter increases from 0.89 nm to 2.49 nm when the particle diameter is 3 nm. A temperature drop at the interface showed that there is interfacial thermal resistance between the neighboring particles. It is also shown that, the smaller the interface size, the bigger the interface thermal resistance.