On the flow characteristics of nanofluids by experimental approach and molecular dynamics simulation

Adding a small amount of nanoparticles to conventional fluids (nanofluids) has been proved to be an effective way for improving capability of heat transferring in base fluids. The change in micro structure of base fluids and micro motion of nanoparticles may be key factors for heat transfer enhancement of nanofluids. Therefore, it is essential to examine these mechanisms on microscopic level. The present work performed a Molecular Dynamics simulation on Couette flow of nanofluids and investigated the microscopic flow characteristics through visual observation and statistic analysis. It was found that the even-distributed liquid argon atoms near solid surfaces of nanoparticles could be seemed as a reform to base liquid and had contributed to heat transfer enhancement. In the process of Couette flow, nanoparticles moved quickly in the shear direction accompanying with motions of rotation and vibration in the other two directions. When the shearing velocity was increased, the motions of nanoparticles were strengthened significantly. The motions of nanoparticles could disturb the continuity of fluid and strengthen partial flowing around nanoparticles, and further enhanced heat transferring in nanofluids.

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Molecular dynamics simulation for flow characteristics in nanochannels and single walled carbon nanotubes

Journal of Physics Conference Series ◽

10.1088/1742-6596/530/1/012048 ◽

2014 ◽

Vol 530 ◽

pp. 012048 ◽

Cited By ~ 1

Author(s):

H Yasuoka ◽

T Imae ◽

M Kaneda ◽

K Suga

Keyword(s):

Carbon Nanotubes ◽

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Flow Characteristics ◽

Single Walled Carbon Nanotubes ◽

Dynamics Simulation ◽

Single Walled Carbon ◽

Walled Carbon Nanotubes

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Molecular Dynamics Simulation of Nanoscale Channel Flows with Rough Wall Using the Virtual-Wall Model

Journal of Nanotechnology ◽

10.1155/2018/4631253 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7

Author(s):

Xiaohui Lin ◽

Fu-bing Bao ◽

Xiaoyan Gao ◽

Jiemin Chen

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Gas Flow ◽

Roughness Element ◽

Fluid Velocity ◽

Flow Characteristics ◽

Rough Wall ◽

Dynamics Simulation ◽

Low Density ◽

Wall Model

Molecular dynamics simulation is adopted in the present study to investigate the nanoscale gas flow characteristics in rough channels. The virtual-wall model for the rough wall is proposed and validated. The computational efficiency can be improved greatly by using this model, especially for the low-density gas flow in nanoscale channels. The effect of roughness element geometry on flow behaviors is then studied in detail. The fluid velocity decreases with the increase of roughness element height, while it increases with the increases of element width and spacing.

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The effect of nanoparticle size and nanoparticle aggregation on the flow characteristics of nanofluids by molecular dynamics simulation

Advances in Mechanical Engineering ◽

10.1177/1687814019889486 ◽

2019 ◽

Vol 11 (11) ◽

pp. 168781401988948 ◽

Cited By ~ 4

Author(s):

Lingling Bao ◽

Chaoyang Zhong ◽

Pengfei Jie ◽

Yan Hou

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Velocity Profile ◽

Flow Characteristics ◽

Maximum Velocity ◽

Velocity Profiles ◽

Dynamics Simulation ◽

Nanoparticle Size ◽

Nanoparticle Aggregation ◽

Nanoparticle Sizes

Molecular dynamics simulation is used to investigate the flow characteristics of Cu–Ar nanofluids considering the influence of nanoparticle size and nanoparticle aggregation. Nanofluids viscosity is calculated by equilibrium molecular dynamics based on Green–Kubo equation. Results demonstrate that the viscosity of nanofluids decreases with the increase of nanoparticle size. In addition, nanoparticle aggregation results in the increase of the nanofluids viscosity. Compared with nanoparticle size, nanoparticle aggregation has a larger impact on viscosity. Nanofluids flowing in parallel-plate nanochannels are simulated. The velocity profiles are studied through three nanoparticle sizes (11.55, 14.55, and 18.33 Å) and four nanoparticle aggregate configurations. Results show that the velocity profile of 14.55 Å nanoparticle size is larger than that of other two nanoparticle sizes. As for four nanoparticles, the nanoparticles clustering as a line leads to the maximum velocity profile, while the nanoparticles clustering as a cube causes the minimum velocity profile. Compared with viscosity, nanoparticle aggregation has a greater effect on the velocity profile. When the nanoparticles are evenly distributed, the influence of viscosity on velocity profiles is dominant. Otherwise, the aggregation, aggregate configuration, and distribution of nanoparticles have a dominant impact on the flow characteristics of nanofluids.

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