Thermal conductivity of molten alkali halides: Temperature and density dependence.
Thermal conductivity of molten alkali halides: Temperature and density dependence.
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DOI：
10.1063/1.3064588
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发表时间：
2009-01
期刊：
影响因子：
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通讯作者：
N. Ohtori;Taku Oono;K. Takase
中科院分区：
文献类型：
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作者：
N. Ohtori;Taku Oono;K. Takase
通过在 Fumi-Tosi 势模型框架内使用分子动力学模拟，评估了一系列熔融碱金属卤化物的热导率。尽管计算结果显示比实验结果大 0%-50%（具体取决于系统），但它们在显示负温度和离子质量依赖性方面彼此一致。为了更详细地阐明负温度依赖性的原因，对所有碱金属氯化物和所有卤化钠在恒温或恒定密度下的导热率进行了评估。计算表明，热导率很大程度上取决于密度，但与温度的关系不大。虽然能流的自相关函数的积分值随着温度的增加而增加，但这被与热导率相关的温度倒数因子抵消了。随着密度的增加，积分值增加，这主导了热导率的行为。通过对不同离子质量的重复计算，我们得出导热系数是m(-1/2)(N/V)(2/3)的函数，其中m是阴离子和阳离子之间离子质量的几何平均值，N/V是数密度。
The thermal conductivities of a series of molten alkali halides have been evaluated by using molecular dynamics simulation within the framework of Fumi-Tosi potential models. Although the calculated results showed 0%-50% larger values than experimental results depending on system, they are in agreement with each other in showing both negative temperature and ionic mass dependence. In order to clarify the cause of the negative temperature dependence in more detail, the thermal conductivity under constant temperature or constant density was evaluated for all alkali chlorides and all sodium halides. The calculations reveal that the thermal conductivity depends strongly on density but only weakly on temperature. While the integrated value of the autocorrelation function for energy current increases with temperature, this is canceled out by the reciprocal temperature factor in relation to the thermal conductivity. With increasing density the integrated value increases, and this dominates the behavior of the thermal conductivity. By repeating the calculations with different ionic masses, we have concluded that the thermal conductivity is a function of m(-1/2)(N/V)(2/3), where m is the geometric mean of ionic mass between anion and cation and N/V is the number density.