Heat transport in liquid water at extreme pressures: A non equilibrium molecular dynamics study
Heat transport in liquid water at extreme pressures: A non equilibrium molecular dynamics study
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DOI：
10.1016/j.molliq.2012.09.013
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发表时间：
2013-09
影响因子：
6
通讯作者：
F. Bresme;F. Römer
中科院分区：
文献类型：
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作者：
F. Bresme;F. Römer
我们调查的结构和热传输的液态水在高压和高温下，1-50千巴和300-600 K，即，在一个区域的相图是具有挑战性的实验研究。采用平衡态和非平衡态分子动力学模拟方法，结合TIP 4P/2005水模型，计算了液态水的结构和热导率。在20-50 kbar的极端压力下，氢键网络的四面体有序特性被严重破坏，液体径向分布函数变得与简单液体非常相似。在这些极端条件下，热导率并不具有异常行为，并且随着温度的降低而降低，如在广泛的简单液体中所观察到的。的热导率与温度和压力的依赖关系如下实验观察，我们发现，它可以准确地预测在液体的等温压缩性方面，通过使用修改后的Leibfried-Schlömann方程。我们还分析了热导率是否遵循硬球流体的T标度行为特征，这是在分析高压和高温实验数据后提出的行为。经过仔细检查，我们发现这种缩放行为在模拟和实验数据的明显偏差。
We investigate the structure and heat transport of liquid water at high pressures and temperatures, 1–50 kbar and 300–600 K, ie, in a region of the phase diagram that is challenging for experimental investigations. Using equilibrium and non equilibrium molecular dynamics simulations and the TIP4P/2005 water model, we compute the structure and thermal conductivity of liquid water. At extreme pressures, 20–50 kbar the tetrahedral order characteristic of the hydrogen bonded network is severely disrupted, and the liquid radial distribution function becomes very similar to that of simple liquids. At these extreme conditions the thermal conductivity does not feature an anomalous behavior, and decreases with temperature as observed in a wide range of simple liquids. The dependence of the thermal conductivity with temperature and pressure follows experimental observations, and we find that it can be accurately predicted in terms of the liquid isothermal compressibility, by using a modified Leibfried–Schlömann equation. We also analyze whether the thermal conductivity follows the T scaling behavior characteristic of hard sphere fluids, a behavior that has been suggested following the analysis of high pressure and high temperature experimental data. Upon close inspection we find clear deviations from this scaling behavior both in simulation and experimental data.