Molecular dynamics study of slip properties of liquid lithium on α-Fe （100） surface

doi:10.7523/j.ucas.2024.047

Abstract

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

CLC Number:

O551.3

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.

Figures/Tables 11

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

Fig.2 Definition of slip length Ls in Couette flow

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

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

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

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

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

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

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

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

Fig.11 Relationship between critical height k and temperature

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