分子動力学法を用いた気液相変化シミュレーション

这项研究的主要目的是了解在不同的种子配置、大小和过饱和度比下发生的异质成核现象。本财年的计划是将研究从单原子过饱和蒸气扩大到水蒸气，并对碳和硫酸颗粒作为前体进行模拟。此外，最终目标是建立一个包含尺寸、形状和过饱和度比如何改变成核的数值模型。修改了研究方向，并对纳米管种子的成核和凝聚进行了深入的研究。选择纳米管来验证带有孔洞的种子将如何改变均匀成核特性。此外，管子的两端都放了一个盖子，以消除使种子成为圆柱体的气孔。在中空圆柱体中填充了分子，并比较了中空圆柱体和填充版本种子上的生长情况，以证实质量效应的存在。计划中的这一修改被确定为更重要的是理解基本几何结构如何改变成核特性，而不是对碳或硫酸等特定分子进行研究。目前正在对水蒸气进行计算，研究结果将于明年公布。数值模型也在构建中。该模型考虑了种子大小效应、开尔文效应、长宽比效应、孔道效应、质量效应和过饱和度比效应。研究结果已发表在各种期刊和会议上。

The primary objective of this research was to understand the heterogeneous nucleation phenomena occurring on various seed configurations, sizes, and supersaturation ratios. The plan for this fiscal year was to expand the research from a monatomic supersaturated vapor to water vapor, and carry out simulations for carbon and sulfuric acid particles acting as precursors. Additionally, developing a numerical model that incorporates how the size, shape, and supersaturation ratio alters nucleation was the final goal.The direction of the study was modified and a thorough study on nucleation and condensation with nanotube seeds was conducted. A nanotube was selected to verify how a seed with a pore would alter the homogeneous nucleation characteristics. Furthermore, a lid was placed on each end of the tube to eliminate the pore making the seed a cylinder. The hollow cylinder was filled with molecules, and the growth on the seeds for the hollow cylinder and filled version were compared to confirm the existence of a mass effect. This modification in the plan was decided to be more essential in understanding how fundamental geometry alters nucleation characteristics rather than performing studies on specific molecules such as carbon or sulfuric acid.Calculations for the water vapor are being conducted, and the results of the study will come out next year. The numerical model is also being constructed. The model incorporates a seed size effect, Kelvin effect, aspect ratio effect, pore effect, mass effect, and supersaturation ratio effect.The results from the research have been published and presented in various journals and conferences.