均相核化率数学模型的改进研究

针对均相核化率求解中存在对表面自由能数值估计过高和对核化临界功估算过大使核化率数值过低等问题，本文通过理论推导对表面自由能数值进行了定量修正，并提出了核化立方体微团的方法。在提出的核化立方体微团方法中，本文认为能量达到临界功的单个分子并不会立即引发核化，而是只有当形成一个立方体微团的所有分子总能量达到临界功时相变才会发生。本文根据改进的表面自由能模型和核化立方体微团的假设对均相核化率数学模型进行了改进，并利用改进的核化率数学模型对水在42℃至300℃下的核化率进行了求解。研究结果表明，与传统的均相核化率数学模型相比，改进的核化率数学模型能较好的用于求解均质相变条件下的核化率。

A revised mathematical model of the homogeneous nucleation rate

Since the surface tension value under a plane surface is too high and the calculated critical work to trigger nucleation is too low, the surface tension value under a concave surface has been quantitatively revised based on theoretical deductions and an assumption of a cubic molecular group. On the basis of this assumption, it is shown that nucleation will occur only if energy of all the molecules in the cubic group is larger than the nucleation barrier. The new model has been used to solve the nucleation rate in the temperature range 42 to 300℃ and has been validated; thus the model can be used to solve for the homogeneous nucleation rate. 