Lee B Y, Wei P S
Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan, ROC.
Heliyon. 2023 Jul 22;9(8):e18163. doi: 10.1016/j.heliyon.2023.e18163. eCollection 2023 Aug.
Mechanisms of the length and maximum radius of lotus-type or single pores in ice or nonmetals satisfied by Henry's law at gas-liquid interfaces dissolved by a gas during unidirectional solidification are rigorously investigated and supported by a Table from algebraic predictions involving different dimensionless working parameters. Lotus-type porous materials characterized by directional properties have been often used as functional materials in food, biomedical, and micro- and nano-technologies. Following previous work taking into account solute amount and transport within the pore, and concentration boundary layers on the advancing solid-liquid interface and bubble cap, and the Young-Laplace equation and Henry's law at liquid-gas interfaces, the algebraic study further provides a Table for a quantitative and extensive understanding of different mechanisms of length and maximum radius. Dimensionless parameters include solute transport parameters of Henry's law constant, mass transfer coefficient, partition coefficient, solute gas amount in imposed ambient, and solute transport parameter, and fluid and thermal parameters of solidification rate, imposed gas pressure, hydrostatic pressure, and geometrical parameter of inter-pore spacing. The controlling of the shapes of lotus-type pores is achieved by a good comparison between predicted maximum diameter and inter-pore spacing during freezing of water dissolved by oxygen gas.
对单向凝固过程中，气液界面处符合亨利定律的冰或非金属中莲花型或单孔的长度和最大半径机制进行了严格研究，并通过一个包含不同无量纲工作参数的代数预测表予以支持。具有定向特性的莲花型多孔材料常被用作食品、生物医学以及微纳技术中的功能材料。在之前考虑孔隙内溶质数量和传输、推进的固液界面和气泡帽上的浓度边界层以及液-气界面处的杨-拉普拉斯方程和亨利定律的工作基础上，该代数研究进一步提供了一个表格，以便对长度和最大半径的不同机制进行定量且广泛的理解。无量纲参数包括亨利定律常数的溶质传输参数、传质系数、分配系数、施加环境中的溶质气体量和溶质传输参数，以及凝固速率、施加气体压力、静水压力和孔间距几何参数的流体和热参数。通过比较预测的最大直径和氧气溶解水冻结过程中的孔间距，实现了对莲花型孔形状的控制。
