-
采用分子动力学模拟方法研究纳米气泡逐渐凹陷并发展至溃灭的过程，本文主要研究冲击速度和气泡尺寸对纳米气泡溃灭的动力学特性影响机制。结果表明：纳米气泡溃灭大体上经历三个阶段。首先是气泡外侧水分子压缩阶段，然后是冲击波导致液膜稳定结构被破坏阶段，最终发展至气泡完全溃灭阶段；在冲击速度较大时，较小尺寸气泡在更强的冲击效果作用下，气泡溃灭时间更短；纳米气泡溃灭后高速射流后在速度等高线右端形成凸起，随着气泡尺寸和冲击速度增大，凸起程度就越大，水分子向气泡中心汇集，在气泡上方和下方形成涡旋结构，有效的增强了流体内部传质作用；随着气泡尺寸和冲击速度的增大，气泡周围密度也逐渐增大，气泡完全时溃灭时局部密度可达1.5 g/cm3附近；当气泡体系衰减至一半时，出现水锤冲击效应，随着气泡尺寸和冲击速度的增大，水锤冲击作用愈发明显，对于up=3.0 km/s，D=10 nm的纳米气泡结构塌陷后射流水锤冲击所形成的局部压强可达30 GPa。A molecular dynamics simulation method is used to study the process of nanobubbles under the action of shock waves, which gradually depresses and develops to collapse, and this paper focuses on the mechanism of the impact velocity and bubble size on the kinetic properties of nanobubble collapse. The results show that the collapse of nanobubbles goes through three stages. The preferred stage is the compression of water molecules on the outside of the bubble, followed by the destruction of the stable structure of the liquid film caused by the shock wave, and finally develops to the stage of complete bubble collapse; when the impact velocity is larger, the smaller size bubbles have shorter bubble collapse time under the action of the stronger impact effect; the nanobubbles form a bulge at the right end of the velocity contour after the collapse of the high-speed jet, and the degree of the bulge increases with the increase of the bubble size and the impact velocity, and water molecules move to the center of the bubbles. Large, water molecules to the center of the bubble convergence, the formation of vortex structure above and below the bubble, effectively enhancing the fluid internal mass transfer; with the increase in bubble size and impact velocity, the density around the bubble is also gradually increasing, the bubble completely collapsed when the local density up to 1.5 g/cm3 nearby; water hammer impact time in the bubble volume attenuation of 50% after the increase in bubble size and impact velocity, water hammer impact is more and more important, the water hammer impact is more and more important. With the increase of bubble size and impact velocity, the water hammer impact is more and more obvious, for up=3.0 km/s, D=10 nm nano-bubble structure after the collapse of the jet water hammer impact formed by the local pressure up to 30 GPa.
-
Keywords:
- nanobubbles /
- molecular dynamics simulations /
- bubble collapse /
- water hammer shock
-
[1] Ma Y, Wu J, Zhou W 2024 J. Environ. Eng. Technol. 14 1141 (in Chinese) [马艳, 吴俊, 周维 2024 环境工程技术学报 14 1141]
[2] Yang L, Liao C H, Zhu Y Z, Chen H J, Jin Q F 2012 Chem. Ind. Eng. Prog. 31 1333 (in Chinese) [杨丽, 廖传华, 朱跃钊, 陈海军, 金勤芳 2012 化工进展 31 1333]
[3] Zhang L J, Zheng J, Wen B, Hu J 2024 Sci. Sin. Chem. 54 85 (in Chinese) [张立娟, 郑晋, 文博, 胡钧 2024 中国科学:化学 54 85]
[4] Zhang M, Song Z Z, Sun S S, Zhang Z Y, Mu H Y, Zhao L P, Li Y F, Zhang Z Z 2016. J. Environ. Eng. 10 599 (in Chinese) [张敏, 宋昭峥, 孙珊珊, 张志勇, 穆红岩, 赵立平, 李永峰, 张忠智 2016 环境工程学报 10 599]
[5] Zhai W Z, Wang Y G, Wang X, Dong J, Wang H J 2018 J. Environ. Sci. Manage. 43 95 (in Chinese) [翟伟哲, 王永刚, 王旭, 董婧, 王恒嘉 2018 环境科学与管理 43 95]
[6] Li H Z, Hu L M, Xin H B 2015 J. Geotech. Eng. 37 115 (in Chinese) [李恒震, 胡黎明, 辛鸿博 2015 岩土工程学报 37 115]
[7] Cook S S 1928 Proc. R. Soc. Lond. A 119 481
[8] Obara T B, Bourne N K, Field J E 1995 Wear 186 388
[9] Zhan S P 2022 Ph.D Dissertation (Beijing: Academy of Machinery Science and Technology) (in Chinese) [詹胜鹏 2022 博士学位论文 (北京:机械科学研究总院)]
[10] Wang X F, Tao G, Xu N, Wang P, Li Z, Wen P. 2021 Acta Phys. Sin. 70 283 (in Chinese) [王小峰, 陶钢, 徐宁, 王鹏, 李召, 闻鹏 2021 物理学报 70 283]
[11] Rawat S 2023 Phys. Fluids 35 097114
[12] Vedadi M H, Haas S 2011 Appl. Phys. Lett. 99 154105
[13] Zhou Y, Cao D, Zhang X 2022 Nanomaterials 12 2654
[14] Nan N, Si D, Hu G 2018 J. Chem. Phys. 149 074902
[15] Wang X F, Tao G, Wen P, Ren B X, Pang C Q, Du C X 2020 J. Phys. Chem. B 124 9535
[16] Lu X, Yuan B, Zhang X, Yang K, Ma Y 2017 Appl. Phys. Lett. 110 023701
[17] Thompson A P, Aktulga H M, Berger R, Bolintineanu D S, Brown W M, Crozier P S, In ’T Veld P J, Kohlmeyer A, Moore S G, Nguyen T D, Shan R, Stevens M J, Tranchida J, Trott C, Plimpton S J 2022 Comput. Phys. Commun. 271 108171
[18] Stukowski A 2010 Modell. Simul. Mater. Sci. Eng. 18 015012
[19] Berendsen H J C, Grigera J R, Straatsma T P 1987 J. Phys. Chem. 91 6269
[20] Zhou Y, Huang M, Tian F, Shi X, Zhang X 2024 J. Phys. Chem. 160 054109
[21] Rybakov A P, Rybakov I A 1995 Eur. J. Mech. B Fluids 14 323
[22] Vedadi M, Choubey A, Nomura K, Kalia R K, Nakano A, Vashishta P, Van Duin A C T 2010 Phys. Rev. Lett. 105 014503
[23] Hołyst R, Litniewski M, Garstecki P 2010 Phys. Rev. E 82 066309
[24] Zhang A M, Cui P, Wang Y 2013 Exp. Fluids 54 1602
[25] Zhang H, Lu Z, Zhang P, Gu J, Luo C, Tong Y, Ren X 2021 Opt. Laser Technol. 138 106606
[26] Zhan S, Duan H, Pan L, Tu J, Jia D, Yang T, Li J 2021 Phys. Chem. Chem. Phys. 23 8446
计量
- 文章访问数: 129
- PDF下载量: 4
- 被引次数: 0
下载:
