铁团簇对液态锂黏度影响的分子模拟研究

doi:10.7523/j.ucas.2021.0062

摘要/Abstract

摘要： 在磁约束核聚变装置中，液态锂有着广泛用途，例如包层、偏滤器等。由于液态锂具有活跃的物理化学特性，其与结构材料的相容性问题一直是核聚变领域的重要研究方向之一。目前工程上通常采用不锈钢作为液态锂回路的结构材料，锂与铁之间的相容性问题已经得到很多学者的关注。鉴于此，采用分子动力学方法对含有铁团簇的液态锂进行模拟研究，分析铁团簇对液态锂黏度的影响规律和微观机理，考察团簇尺寸、形状和体积浓度的影响。结果表明铁团簇的存在可以显著地改变液态锂的黏度，而且随着团簇尺寸的增加黏度逐渐增大。团簇形状对黏度也有一定的影响，在相同体积的条件下，表面积越大影响越大。此外，发展了纳米流体黏度计算模型，可以很好地拟合分子动力学的模拟结果。

关键词: 分子动力学, 黏度, 扩散系数, Fe-Li纳米流体, 液态锂

Abstract: Liquid lithium has a wide range of applications in magnetic confinement fusion devices, such as blanket, divertor, etc. Due to the active physical and chemical properties of liquid lithium, its compatibility with structural materials has always been one of the important issues in the field of nuclear fusion. Considering that stainless steel is usually used as the structural material of the liquid lithium circuit in engineering, the compatibility between lithium and iron has attracted the attention of many scholars. In view of this, the molecular dynamics method was used to simulate the liquid lithium containing iron clusters. The effects of iron clusters on the viscosity of liquid lithium and the micromechanism were analyzed. The effects of cluster size, shape, and concentration were investigated. The results show that the presence of iron clusters can significantly change the viscosity of liquid lithium, and the viscosity gradually increases with the increase of cluster size. The cluster shape also has a certain effect on the viscosity. Under the condition of the same volume, the larger the surface area, the greater the effect. In addition, we have also developed a computational model for the viscosity of nanofluid, which can well fit the simulation results of molecular dynamics.

Key words: molecular dynamics (MD), viscosity, diffusion coefficient, Fe-Li nanofluid, liquid lithium

中图分类号:

O551.3

徐博, 刘松畅, 余新刚. 铁团簇对液态锂黏度影响的分子模拟研究[J]. 中国科学院大学学报, 2023, 40(2): 165-172.

XU Bo, LIU Songchang, YU Xingang. Molecular simulation study of the effect of iron clusters on the viscosity of liquid lithium[J]. Journal of University of Chinese Academy of Sciences, 2023, 40(2): 165-172.

参考文献

[1] 胡建生,左桂忠,王亮,等. 磁约束核聚变装置等离子体与壁相互作用研究简述[J]. 中国科学技术大学学报, 2020, 50(9):1193-1217.DOI:10.3969/j.issn.0253-2778.2020.09.001.
[2] Mazzitelli G, Apicella M L, Frigione D, et al. FTU results with a liquid lithium limiter[J]. Nuclear Fusion, 2011, 51(7):073006.DOI:10.1088/0029-5515/51/7/073006.
[3] Chopra O K, Smith D L. Influence of temperature and lithium purity on corrosion of ferrous alloys in a flowing lithium environment[J]. Journal of Nuclear Materials, 1986, 141/142/143:584-591.DOI:10.1016/0022-3115(86)90058-9.
[4] Chopra O K, Smith D L. Compatibility of ferritic steels in forced circulation lithium and Pb-17Li systems[J]. Journal of Nuclear Materials, 1988, 155/156/157:715-721.DOI:10.1016/0022-3115(88)90402-3.
[5] Flament T, Tortorelli P, Coen V, et al. Compatibility of materials in fusion first wall and blanket structures cooled by liquid metals[J]. Journal of Nuclear Materials, 1992, 191/192/193/194:132-138.DOI:10.1016/s0022-3115(09)80020-2.
[6] Gan X L, Xiao S F, Deng H Q, et al. Clustering of Fe atoms in liquid Li and its effect on the viscosity of liquid Li[J]. Nuclear Fusion, 2016, 56(4):046004.DOI:10.1088/0029-5515/56/4/046004.
[7] Lou Z Y, Yang M L. Molecular dynamics simulations on the shear viscosity of Al₂O₃ nanofluids[J]. Computers & Fluids, 2015, 117:17-23.DOI:10.1016/j.compfluid.2015.05.006.
[8] Rudyak V Y, Krasnolutskii S L. Simulation of the nanofluid viscosity coefficient by the molecular dynamics method[J]. Technical Physics, 2015, 60(6):798-804.DOI:10.1134/s1063784215060237.
[9] Lu G, Duan Y Y, Wang X D. Surface tension, viscosity, and rheology of water-based nanofluids:a microscopic interpretation on the molecular level[J]. Journal of Nanoparticle Research, 2014, 16(9):1-11.DOI:10.1007/s11051-014-2564-2.
[10] Gan X L, Xiao S F, Deng H Q, et al. Atomistic simulations of the Fe(001)-Li solid-liquid interface[J]. Fusion Engineering and Design, 2014, 89(12):2894-2901.DOI:10.1016/j.fusengdes.2014.06.018.
[11] Hoover W G. Canonical dynamics:equilibrium phase-space distributions[J]. Physical Review A, General Physics, 1985, 31(3):1695-1697.DOI:10.1103/physreva.31.1695.
[12] Nosé S. A unified formulation of the constant temperature molecular dynamics methods[J]. The Journal of Chemical Physics, 1984, 81(1):511-519.DOI:10.1063/1.447334.
[13] Parrinello M, Rahman A. Crystal structure and pair potentials:a molecular-dynamics study[J]. Physical Review Letters, 1980, 45(14):1196.DOI:10.1103/physrevlett.45.
[14] Mouas M, Gasser J G, Hellal S, et al. Diffusion and viscosity of liquid tin:Green-Kubo relationship-based calculations from molecular dynamics simulations[J]. The Journal of Chemical Physics, 2012, 136(9):094501.DOI:10.1063/1.3687243.
[15] Müller-Plathe F. A simple nonequilibrium molecular dynamics method for calculating the thermal conductivity[J]. The Journal of Chemical Physics, 1997, 106(14):6082-6085.DOI:10.1063/1.473271.
[16] Plimpton S. Fast parallel algorithms for short-range molecular dynamics[J]. Journal of Computational Physics, 1995, 117(1):1-19.DOI:10.1006/jcph.1995.1039.
[17] Stukowski A. Visualization and analysis of atomistic simulation data with OVITO:the open visualization tool[J]. Modelling and Simulation in Materials Science and Engineering, 2010, 18(1):015012.DOI:10.1088/0965-0393/18/1/015012.
[18] Ohse R W. Handbook of thermodynamic and transport properties of alkali metals[M]. Oxford:Blackwell Scientific Publications, 1985.
[19] Shpilrain E E, Soldaten Y A, Yakimovi K A, et al. Experimental investigation of thermal and electrical properties of liquid alkali metals at high temperatures[J]. High Temperature, 1965, 3(6):870.
[20] Novikov I I, Soloviev A N, Khabakhnasheva E M, et al. The heat-transfer and high-temperature properties of liquid alkali metals[J]. Journal of Nuclear Energy (1954), 1957, 4(3):387-408.DOI:10.1016/0891-3919(57)90218-8.
[21] Blagoveshchenskii N M, Novikov A G, Savostin V V. Self-diffusion in liquid lithium from coherent quasielastic neutron scattering[J]. Physica B:Condensed Matter, 2012, 407(23):4567-4569.DOI:1016/j.physb.2012.07.027.
[22] Wang Z H, Ni M J. Self-diffusion coefficient study of liquid lithium[J]. Heat and Mass Transfer, 2012, 48(2):253-257.DOI:10.1007/s00231-011-0874-9.
[23] He Y R, Jin Y, Chen H S, et al. Heat transfer and flow behaviour of aqueous suspensions of TiO₂ nanoparticles (nanofluids) flowing upward through a vertical pipe[J]. International Journal of Heat and Mass Transfer, 2007, 50(11/12):2272-2281.DOI:10.1016/j.i.jheatmasstransfer.2006.10.024.
[24] Cui W Z, Shen Z J, Yang J G, et al. Effect of chaotic movements of nanoparticles for nanofluid heat transfer augmentation by molecular dynamics simulation[J]. Applied Thermal Engineering, 2015, 76:261-271.DOI:10.1016/j.applthermaleng.2014.11.030.
[25] Zwanzig R. On the relation between self-diffusion and viscosity of liquids[J]. The Journal of Chemical Physics, 1983, 79(9):4507-4508.DOI:10.1063/1.446338.
[26] Chandrasekar M, Suresh S, Chandra Bose A. Experimental investigations and theoretical determination of thermal conductivity and viscosity of Al₂O₃/water nanofluid[J]. Experimental Thermal and Fluid Science, 2010, 34(2):210-216.DOI:10.1016/j.expthenmflusci.2009.10.022.
[27] Mano J F, Pereira E. Data analysis with the vogel-fulcher-tammann-Hesse equation[J]. The Journal of Physical Chemistry A, 2004, 108(49):10824-10833.DOI:10.1021/jp0484433.
[28] Einstein A. A new determination of the molecular dimensions[J]. Annalen Der Physik, 1911, 339(3):591-592.
[29] Rudyak V Y, Minakov A V. Thermophysical properties of nanofluids[J]. The European Physical Journal E, 2018, 41(1):15.DOI:10.1140/epje/i2018-11616-9.
[30] Oliver D R, Ward S G. Relationship between relative viscosity and volume concentration of stable suspensions of spherical particles[J]. Nature, 1953, 171(4348):396-397.DOI:10.1038/17139660.
[31] Avsec J, Oblak M. The calculation of thermal conductivity, viscosity and thermodynamic properties for nanofluids on the basis of statistical nanomechanics[J]. International Journal of Heat and Mass Transfer, 2007, 50(21/22):4331-4341.DOI:10.1016/j.ijheatmasstransfer.2007.01.064.