Abstract:

The physical mechanism of crystal growth was analyzed using heat and mass transfer equations, Navier-Stokes equations and growth dynamics in this paper. Cellular automata (CA) method was used to form a phase change model. The desublimation process of water vapor and CO₂ in liquid methane is observed by computer simulation. Not only the two-dimensional simulation results of ice crystal growth, but also the two-dimensional and three-dimensional simulation results of CO₂ crystal growth in liquid methane were obtained. Results show that this model could simulate water and CO₂ crystallization under sub-cooled and supersaturated environment. The two-dimensional ice crystal result is very similar to the real ice crystal with topological structure. CO₂ crystal has simpler structure and the simulation results confirm to the characters of authentic CO₂ crystal. This model can be improved to analyze the water and CO₂ crystallization in liquid natural gas (LNG) and may be used to improve the technology processes of storage, transportation and utilization of LNG.

摘要：

利用热质传输方程、流体动力学方程、连续性方程和生长动力学规律分析了晶体生长的物理机制，同时利用元胞自动机法建立了凝华相变的模型，通过计算机模拟了水蒸气以及CO₂在低温液态甲烷中凝华形成晶体的过程，得到了冰晶的二维模拟结果以及CO₂晶体的二维和三维模拟结果。结果显示该模型能够模拟出指定温度和过饱和度下的冰晶以及CO₂晶体生长过程。冰晶以及CO₂晶体生长过程中具有一定的各向异性。该模型可以用于分析LNG中冰晶以及CO₂晶体的形成，有利于改善LNG储存运输使用等过程中的技术流程。