Abstract:

Heat transfer is one of the basic issues in chemical production, and thermal conductivity is an important thermodynamic data in the design of chemical product production processes. In this paper, nonequilibrium molecular dynamics methods are used to simulate the heat transfer of liquid alcohols at four different temperatures, and the thermal conductivity of the corresponding conditions is obtained. The average relative deviation between the calculated value and the experimental value was 3.77%. Through the decomposition of heat flux, it was found that molecular kinetic energy, Coulomb interaction and intramolecular dihedral angle contribute the most to the heat conduction of alcohols. At the same time, as the molecular volume increases, the thermal conduction pathway of the intramolecular interaction term gradually dominates, indicating that the thermal conduction mechanism of alcohols has a significant relationship with the molecular structure. In addition, as the temperature elevates, the heat flux transmitted through the molecular kinetic energy, intermolecular Coulomb interaction, and the intramolecular angle bending and bond stretching term increases, while the heat flux transmitted through the molecular potential energy decreases significantly. This work provides a microscopic explanation for the effects of the structure and temperature of liquid alcohols on thermal conductivity, and provides a micro foundation for the study of heat conduction of liquid alcohols.

Key words: heat transfer, thermal conductivity, thermal conduction mechanism, molecular dynamics simulation, alcohol

摘要：

传热是化工生产的基本问题之一，热导率是化工产品生产工艺设计中一类重要的热力学数据。通过非平衡分子动力学方法模拟了8种液态醇类有机物在不同温度下的导热过程。热导率计算值与实验值的平均相对偏差为3.77%。通过对热流的分解发现，分子动能、分子间库仑相互作用和分子内的二面角对醇类有机物的热传导影响较大。同时随着分子链增长，通过分子内相互作用进行的热传导逐渐占主导作用，表明醇类有机物的热能传输机理与分子结构有显著关系。此外，随着温度的升高，通过分子的动能、分子间库仑作用和分子内键角、键伸缩作用项传输的热流增大，表明温度对液态醇类有机物的热传导也有一定影响。本工作从微观分子间和分子内作用分析了液态醇类有机物结构和温度对热导率的影响，为液态有机物的热传导研究提供了微观依据。

关键词: 传热, 热导率, 导热机理, 分子动力学模拟, 醇