过冷液体的冻结过程中的温度分布与相界面的位置可以通过求解Stefan问题来预测。经典Stefan问题中认为相界面的温度为凝固点，但在快速冻结发生时由于非平衡条件的影响，相界面的温度会低于凝固点，此时如何确定相界面的温度是一个难点。通过分子动力学模拟方法研究了过冷水快速冻结过程，得到了相界面在不同移动速度下相界面温度的变化规律。相界面过冷度为0~5K范围内，界面动力学系数可以近似为0.55m·s-1·K-1，即相界面移动速度每增加0.55m/s，相界面的温度降低1K。对于更高的相界面过冷度，相界面移动速度和相界面过冷度的关系可用一个二次函数来描述。该相界面温度确定方法可应用于过冷水快速冻结的数值模拟。
The interface position in the freezing of supercooled water could be predicted by solving the Stefan problem. In classical Stefan problem, the interface temperature is set as a constant equal to the melting temperature of the liquid phase. In problems involving rapid solidification, the interface temperature could be lower than the melting temperature due to the non-equilibrium condition. De-termining the interface temperature becomes a challenge. Molecular dynamics method is applied to simulate rapid freezing of super-cooled water. A method to determine the interface temperature is developed. If the interface supercooling temperature is in the range of 0 K to 5 K, the interface kinetic coefficient could be 0.55m·s-1·K-1, Which indicates that interface temperature would decrease 1K if the interface velocity increases 0.55 m/s. For larger supercooling temperature, relationship of the interface velocity and the interface temperature is a quadratic function. The relationship could be applied to the numerical simulation of rapid freezing of supercooled water.
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