Development of practical simulator to design crystallization and surface reaction process in supercritical fluids

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K05132
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 27010:Transport phenomena and unit operations-related
• Research Institution: Hachinohe National College of Technology
• Principal Investigator: Honma Tetsuo 八戸工業高等専門学校, その他部局等, 准教授 (10369910)
• Co-Investigator(Kenkyū-buntansha): 百瀬 健 東京大学, 大学院工学系研究科(工学部), 講師 (10611163) ; 秋月 信 東京大学, 大学院新領域創成科学研究科, 講師 (30707188) ; 佐藤 剛史 宇都宮大学, 工学部, 教授 (60375524)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 核生成 / 晶析 / 超臨界流体 / 分子シミュレーション / 離散要素法

Outline of Final Research Achievements

Density functional theory calculations and molecular dynamics simulation have been performed to understand nucleation process in molecular level. Since model nucleus of ZnO for DFT calculation was ideal structure, the free energy change on nucleation process was negative. Therefore, the activation energy of nucleation was evaluated by means of MD simulation. According to MD simulation study, ZnO forms small-size chain-like structure as a precursor of nucleus, followed by large-size cluster consisting of hexagonal ring-like structure were formed. The large-size cluster may be transformed into zinc oxide crystal by stacking. Temperature and ZnO concentration influence on nucleation rate is significant, but they have no influence on the mechanism of nucleation. Computational fluid dynamics and discrete element method has been performed particle motion in a T-shaped tubular reactor. It has a good prospect to develop a simulator for particle motion in fluid.

Free Research Field

化学工学・超臨界流体工学

Academic Significance and Societal Importance of the Research Achievements

流体中における晶析・表面反応過程は新規材料創成に不可欠な技術であるが、その応用に際しては核生成モデルの構築が必須である。本研究の結果は、核生成過程においてミクロスケールからその解明に取り組み、得られた知見を実機に適用できる実用シミュレーターへ応用することを志向しており、その社会的意義は大きいと考える。