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近年来, 纳米技术的发展使得非球形纳米颗粒的工业化应用成为可能, 形貌各向异性的非球形颗粒有利于改善纳米流体的传热性能. 有研究表明, 将Janus 纳米颗粒引入到基液中可进一步增强纳米流体的导热特性. 本文设计了一种具备亲水侧面和疏水底面的锥形Janus纳米颗粒, 并将其引入到基液中形成锥形Janus纳米流体, 采用分子动力学模拟计算了锥形和球形两种Janus纳米流体的热导率, 对其导热机理进行计算分析. 结果表明, 锥形颗粒表面的类固液体层效应更明显, 其在基液中的扩散能力更强, 因此锥形纳米流体具备比球形纳米流体更强的导热性能. 对于Janus纳米流体, Janus颗粒独特的不对称结构使得其在基液中的布朗运动更为强烈, 有效增强了纳米流体内部的传热效率. 因此, 非球形颗粒与Janus颗粒的结合可进一步提高纳米流体的导热性能, 为开发新型传热工质提供了新的思路.It has been reported that the thermal conductivity of the nanofluids can be enhanced by adding Janus nanoparticles into the base fluid. Additionally, the non-spherical nanoparticles also affect the thermal characteristics of nanofluids. In this work, conical nanoparticles are designed as Janus nanoparticles with hydrophilic side and hydrophobic bottom, which are suspended in the base fluid to form cone-shaped Janus nanofluids. By using molecular dynamics (MD) simulations, it is found that the thermal conductivity of conical Janus nanofluids can be enhanced by 43.4% compared with that of the base fluid, whereas the spherical Janus nanofluids indicate an increase of 33.7% under the same volume fraction. According to MD simulation results of the RDF and diffusion coefficients of solid particle and base fluid, the increased thermal conductivity observed in conical nanofluids can be attributed to the higher liquid layer density and the enhanced Brownian motion of the conical particles. For Janus nanofluids, the asymmetrical structure of Janus nanoparticles leads to higher diffusion coefficient than that of normal particles, which enhances the colliding possibility of Janus nanoparticles with surrounding liquid molecules, thus resulting in enhanced heat transfer in Janus nanofluids. In this paper, both fixed and unfixed particles are considered to explore the influence of particle diffusion on nanofluids. Under the fixed condition, the Brownian motion of the nanoparticles is artificially excluded, while under the unfixed condition, the particle can diffuse in the base liquid. It is found that for both spherical and conical Janus nanofluids, the thermal conductivity of Janus nanofluids gradually increases with the augment of asymmetry parameter δ under unfixed conditions. However, under fixed conditions, the thermal conductivity of Janus nanofluids is almost independent of the parameter δ. Therefore, the enhanced Brownian motion of the non-spherical particles is a likely reason of the increased thermal conductivity observed in conical Janus nanofluids. The combination of non-spherical particles and Janus particles provides a promising idea for designing nanofluids with high thermal conductivity.
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Keywords:
- nanofluids /
- non-spherical particles /
- Janus particles /
- thermal conductivity /
- molecular dynamics simulation
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图 2 球形Janus纳米流体和锥形Janus纳米流体模型的初始结构
Fig. 2. Initial structure model of spherical Janus nanofluids and conical Janus nanofluids.
图 3 锥形Janus纳米流体和球形Janus纳米流体在体积分数为1%和2%下的热导率
Fig. 3. Thermal conductivity of base liquid, conical and spherical Janus nanofluids at 1% and 2% volume fractions.
图 4 Janus纳米流体中氩-氩原子的径向分布函数 (a) 二维平面图; (b) 三维立体图
Fig. 4. RDF of argon-argon atoms for different types of Janus nanofluids: (a) Planar graph; (b) three-dimensional graph.
图 5 Janus纳米流体中铜-氩原子的径向分布函数
Fig. 5. Radial distribution function of copper-argon atoms for different types of Janus nanofluids.
图 6 球形纳米流体中氩原子数密度随距离变化图
Fig. 6. Distribution of the number density of argon atoms with distance in spherical nanofluids.
图 7 Janus纳米流体中基液原子的均方位移
Fig. 7. MSD of the base fluid for different types of Janus nanofluids.
图 8 纯氩和不同类型Janus纳米流体中基液的扩散系数
Fig. 8. Diffusion coefficient of base liquid under different conditions of Janus nanofluids and pure argon.
图 9 颗粒不固定和固定情况下(a)球形Janus纳米流体和(b)锥形Janus纳米流体的热导率
Fig. 9. Thermal conductivity of Janus nanofluids under unfixed and fixed conditions for (a) spherical Janus nanofluids and (b) conical Janus nanofluids.
图 10 球形和锥形Janus纳米颗粒MSD随模拟时间的变化图
Fig. 10. Mean square displacement (MSD) of spherical and conical Janus nanoparticles with simulation time.
图 11 球形和锥形Janus纳米颗粒的扩散系数
Fig. 11. Diffusion coefficient of spherical and conical Janus nanoparticles.
类型 Ⅰ Ⅱ Ⅲ Ⅳ Ⅴ c1 1 0.8 0.6 0.4 0.2 c2 1 1.2 1.4 1.6 1.8 δ 0 0.2 0.4 0.6 0.8 
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[1] Wang X F, Ren X X, Qiu C, Cao Y F, Taleb T, Leung V C M 2021 IEEE Netw. 35 280
Google Scholar
[2] Liu M S, Lin M C, Tsai C Y, Wang C C 2006 Int. J. Heat Mass Transf. 49 3028
Google Scholar
[3] Choi S U S, Zhang Z G, Yu W, Lockwood F E, Grulke E A 2001 Appl. Phys. Lett. 79 2252
Google Scholar
[4] Han X F, Lu L W, Yan S Y, Yang X H, Tian R, Zhao X Y 2021 J. Therm. Sci. 30 1581
Google Scholar
[5] Xuan Y M, Li Q 2000 Int. J. Heat Mass Transf. 21 58
[6] Liu B, Liang W H, Luo Z M, Sarvar S, Fereidooni L, Kasaeian A 2024 Mol. Liq. 414 126052
Google Scholar
[7] Xuan Y M, Duan H L, Li Q 2014 RSC Adv. 4 16206
Google Scholar
[8] Rapp B, Hussam A 2023 J. Appl. Phys. 133 134302
Google Scholar
[9] Dai J H, Zhai Y L, Li Z H, Wang H 2024 J. Mol. Liq. 400 124518
Google Scholar
[10] Yu W, Choi S U S 2004 J. Nanopart. Res. 6 355
Google Scholar
[11] 齐凯, 朱星光, 王军, 夏国栋 2024 73 156801
Google Scholar
Qi K, Zhu X G, Wang J, Xia G D 2024 Acta Phys. Sin. 73 156801
Google Scholar
[12] Liu W W, Cui J, Wang J 2023 Phys. Fluids. 35 032004
Google Scholar
[13] Xue L, Keblinski P, Phillpot S R, Choi S U S, Eastman J A 2004 Int. J. Heat Mass Transf. 47 4277
Google Scholar
[14] 张智奇, 钱胜, 王瑞金, 朱泽飞 2019 68 054401
Google Scholar
Zhang Z Q, Qian S, Wang R J, Zhu Z F 2019 Acta Phys. Sin. 68 054401
Google Scholar
[15] Karthik V, Sahoo S, Pabi S K, Ghosh S 2013 Int. J. Therm. Sci. 64 53
Google Scholar
[16] 刘旺旺, 张克学, 王军, 夏国栋 2024 73 075101
Google Scholar
Liu W W, Zhang K X, Wang J, Xia G D 2024 Acta Phys. Sin. 73 075101
Google Scholar
[17] Wang R J, Qian S, Zhang Z Q 2018 Int. J. Heat Mass Transf. 127 1138
[18] Dolatabadi N, Rahmani R, Rahnejat H, Garner C P 2019 RSC Adv. 9 2516
Google Scholar
[19] Roni M R H, Shahadat M R B, Morshed A M M 2021 Micro Nano Lett. 16 221
Google Scholar
[20] Li L, Zhang Y W, Ma H B, Yang M 2010 J. Nanopart. Res. 12 811
Google Scholar
[21] Sarkar S, Selvam R P 2007 J. Appl. Phys. 102 074302
Google Scholar
[22] Du J Y, Su Q M, Li L, Wang R J, Zhu Z F 2021 Int. Commun. Heat Mass Transf. 127 105501
Google Scholar
[23] Pang C W, Jung J, Kang Y T 2014 Int. J. Heat Mass Transf. 72 392
Google Scholar
[24] Zhou L, Zhu J W, Zhao Y F, Ma H H 2022 Int. J. Heat Mass Transf. 183 122124
Google Scholar
[25] Wang X W, Xu X F, Choi S U S 1999 J. Thermophys. Heat Transf. 13 474
Google Scholar
[26] Cui W Z, Shen Z J, Yang J G, Wu S H, Bai M L 2014 RSC Adv. 4 55580
Google Scholar
[27] 朱大海, 于伟, 朱桂华, 张迎春, 谢华清 2020 科学通报 65 222
Google Scholar
Zhu D H, Yu W, Zhu G H, Zhang Y C, Xie H Q 2020 Chin. Sci. Bull. 65 222
Google Scholar
[28] 王军, 崔鑫, 夏国栋 2023 北京工业大学学报 49 1116
Wang J, Cui X, Xia G D 2023 J. Beijing Univ. Technol. 49 1116
[29] Li D, Hong B Y, Fang W J, Guo Y S, Lin R S 2010 Ind. Eng. Chem. Res. 49 1697
Google Scholar
[30] Murshed S M S, Leong K C, Yang C 2005 Int. J. Therm. Sci. 44 367
Google Scholar
[31] 李康睿, 王军, 夏国栋 2025 74 064701
Google Scholar
Li K R, Wang J, Xia G D 2025 Acta Phys. Sin. 74 064701
Google Scholar
[32] Yu L Y, Liu D, Botz F 2012 Exp. Therm. Fluid Sci. 37 72
Google Scholar
[33] 侯泉文, 曹炳阳, 过增元 2009 58 7809
Google Scholar
Hou Q W, Cao B Y, Guo Z Y 2009 Acta Phys. Sin. 58 7809
Google Scholar
[34] Jabbari F, Rajabpour A, Saedodin S 2021 Microfluid. Nanofluid. 25 102
Google Scholar
[35] Zhang L Y, Yu Wei, Zhu D H, Xie H Q, Huang G W 2017 J. Nanomater. 2017 5802016
[36] Cui X, Wang J, Xia G D 2022 Nanoscale 14 99
Google Scholar
[37] Kobayashi Y, Arai N 2019 J. Electrochem. Soc. 166 B3223
Google Scholar
[38] Hong L, Jiang S, Granick S 2006 Langmuir. 22 9495
Google Scholar
[39] Zhao H, Liang F X, Qu X Z, Wang Q, Yang Z Z 2015 Macromolecules. 48 700
Google Scholar
[40] Rudyak V Y, Krasnolutskii S L 2017 Tech. Phys. 62 1456
Google Scholar
[41] Huang J, Sang L X, Yang Q F, Wu Y T 2024 Sol. Energy Mater. Sol. Cells. 277 113150
Google Scholar
[42] Koo J, Kleinstreuer C 2004 J. Nanopart. Res. 6 577
Google Scholar
[43] Naghizadeh J, Rice S A 1962 J. Chem. Phys. 36 2710
Google Scholar
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