液态锂在α-Fe （100）表面滑移特性的分子动力学研究

doi:10.7523/j.ucas.2024.047

摘要/Abstract

摘要：

采用分子动力学方法模拟液态Li在α-铁（Fe）纳米通道中的Couette流动，分析三角形表面粗糙单元对液态Li在α-Fe （100）表面滑移特性的影响。结果表明三角形两侧角度对滑移长度的影响并不显著，但是存在一个临界角度，当三角形两侧角度超过该临界值时，液态Li会在三角形前侧形成微尺度旋涡，显著增加流动阻力，进而引起滑移长度的突然大幅下降；三角形高度对滑移长度具有更加显著的影响，且同样存在一个临界高度，只有当三角形高度超过临界值时才会形成旋涡，否则无论如何改变三角形的角度都不会在三角形附近形成旋涡；温度对于临界角度和临界高度都有一定的影响，随着温度的升高，临界角度和高度都呈下降趋势。

关键词: 分子动力学, 液态锂, Couette流动, 滑移长度

Abstract:

Liquid lithium （Li） has a wide range of applications in nuclear fusion test devices， but the slip characteristics of liquid Li on the surface of solid materials have not been fully studied. In this paper， the Couette flow of liquid Li in α-iron （Fe） nanochannels was simulated by the molecular dynamics method， and the effect of triangular roughness units on the slip characteristics of liquid Li on the α-Fe （100） surface was analyzed. The results show that the influence of the angle on both sides of the triangle on the slip length is not significant， but there is a critical angle， when the angle on both sides of the triangle exceeds the critical value， the liquid Li will form a microscale vortex on the front side of the triangle， which significantly increases the flow resistance， and then causes a sudden and large decrease in the slip length， the critical angle and the height show a downward trend. The height of the triangles has a more pronounced impact on slip length， and a similar critical height exists. Vortices only form when the height exceeds this critical value， regardless of changes to the angles. Temperature has a certain influence on these parameters. As temperature rises， both the critical angle and critical height decrease.

Key words: molecular dynamics, liquid lithium, Couette flow, slip length

中图分类号:

O551.3

屈怀远, 余新刚. 液态锂在α-Fe （100）表面滑移特性的分子动力学研究[J]. 中国科学院大学学报, 2026, 43(4): 471-477.

Huaiyuan QU, Xingang YU. Molecular dynamics study of slip properties of liquid lithium on α-Fe （100） surface[J]. Journal of University of Chinese Academy of Sciences, 2026, 43(4): 471-477.

图/表 11

图1 液态Li在α-Fe粗糙微通道内的Couette流

Fig.1 Atomistic model of liquid Li flow in α-Fe channel with triangle roughness element

图2 Couette流中滑移长度Ls的定义

Fig.2 Definition of slip length Ls in Couette flow

图3 液态Li流速随高度变化的典型分布

Fig.3 Typical distribution of the velocity of Li flow along tunnel height

图4 滑移长度随三角形迎风面角度 α 的变化关系

Fig.4 Slip length as a function of the windward angle α of triangular roughness element

图5 不同迎风面角度 α 三角形粗糙单元附近的流线

Fig.5 Stream lines of liquid Li flow around triangle roughness elements with different windward angles α

图6 滑移长度随三角形背风面角度 β 的变化关系

Fig.6 Slip length as a function of the leeward angle β of triangular roughness element

图7 不同背风面角度 β 三角形粗糙单元附近的流线

Fig.7 Stream lines of liquid Li flow around triangle roughness elements with different leeward angles β

图8 滑移长度随三角形高度k的变化关系

Fig.8 Slip length as a function of height k of triangular roughness element

图9 不同温度条件下滑移长度随三角形迎风面角度 α 的变化关系

Fig.9 Relationship between slip length and windward angle α of triangular roughness element at different temperatures

图10 临界角度 α 和 β 随温度的变化关系

Fig.10 Relationship between critical values of α and β with T

图11 临界高度k随温度的变化关系

Fig.11 Relationship between critical height k and temperature

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