论文标题
剪切下的冰核播种方法
Seeding Method for Ice Nucleation under Shear
论文作者
论文摘要
流体动力流对同质成核的速率产生复杂且深远的后果。我们提出了一种一般形式主义，用于计算简单剪切系统的成核速率。 我们已得出了传统的经典成核理论的扩展，明确体现了剪切速率。种子分子动力学模拟构成了我们方法的骨干。 该框架可用于适度的超冷，在这种温度下，蛮力方法实际上是不可行的。剪切的竞争能量和动力学作用自然来自方程式。 我们展示了如何使用该理论来识别MW水模型的冰核行为的剪切状态，从而统一了文献中报道的不同趋势。在每个温度下，我们在$ 1000-10,000 \ s^{ - 1} $的极限下定义一个交叉剪切速率，以最佳的剪切速率以最大的态度稳定地提高到最大值。 对于$ 235 $，$ 240 $，$ 255 $和$ 260 \ k $，最佳剪切率在$ \ of \ \ 10^6-10^7 \ s^{ - 1} $的范围内。对于非常高的剪切速率，超过$ 10^8 \ s^{ - 1} $，核的构成受到了强烈抑制。我们的结果表明，剪切依赖性成核曲线对温度具有非单调的依赖性。
Hydrodynamic flow can have complex and far-reaching consequences on the rate of homogenous nucleation. We present a general formalism for calculating the nucleation rates of simply sheared systems. We have derived an extension to the conventional Classical Nucleation Theory, explicitly embodying the shear rate. Seeded Molecular Dynamics simulations form the backbone of our approach. The framework can be used for moderate supercoolings, at which temperatures brute-force methods are practically infeasible. The competing energetic and kinetic effects of shear arise naturally from the equations. We show how the theory can be used to identify shear regimes of ice nucleation behaviour for the mW water model, unifying disparate trends reported in the literature. At each temperature, we define a crossover shear rate in the limit of $1000-10,000 \ s^{-1}$, beyond which the nucleation rate increases steadily upto a maximum, at the optimal shear rate. For $235$, $240$, $255$ and $260 \ K$, the optimal shear rates are in the range of $\approx 10^6-10^7 \ s^{-1}$. For very high shear rates beyond $10^8 \ s^{-1}$, nucleation is strongly inhibited. Our results indicate that the shear-dependent nucleation rate curves have a non-monotonic dependence on temperature.
