scholarly journals Molecular Dynamics Simulation of the Shear Viscosity of Molten Alkali Halides

2004 ◽  
Vol 108 (11) ◽  
pp. 3658-3662 ◽  
Author(s):  
Nuno Galamba ◽  
Carlos A. Nieto de Castro ◽  
James F. Ely
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Shear Viscosity ◽  
Alkali Halides ◽  
Dynamics Simulation

Prediction of Thermal Conductivity and Shear Viscosity of Water-Cu Nanofluids Using Equilibrium Molecular Dynamics

2013 ◽  
Author(s):  
Tolga Akıner ◽  
Hakan Ertürk ◽  
Kunt Atalık
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Rheological Properties ◽  
Shear Viscosity ◽  
Effective Properties ◽  
Dynamics Simulation ◽  
Modeling Tools ◽  
Macroscopic Modeling

Nanofluids are new class of fluids which can be used for many engineering applications due to their enhanced thermal properties. The macroscopic modeling tools used for flow simulations usually rely on effective thermal and rheological properties of the nanofluids that can be predicted through various effective medium theories. As these theories significantly under-predict, using correlations based on experimental data is considered as the only reliable means for prediction of these effective properties. However, the behavior might change significantly once the particle material or base fluid change due to different particle fluid interactions in the molecular level. One of the most promising means of modeling effective properties of the nanofluids is the molecular dynamics simulations where all the intermolecular effects can be modeled. This study investigates equilibrium molecular dynamics simulation of the water-Cu nanofluids to predict the thermal and rheological properties. The molecular dynamics simulation is carried out to achieve a thermodynamic equilibrium, based on a state that is defined by targeted thermodynamic properties of the system. The Green-Kubo method is used to predict the thermal conductivity and viscosity of the system. The study considers the use of different combining rules such as Lorentz-Berthelot and sixth-power rules for defining the inter-atomic potentials for water modeled by SPC/E and nanoparticles modeled by Lennard-Jones potential. The predicted effective properties that are thermal conductivity and shear viscosity are then compared with experimental data from literature. The predicted transport properties at different temperatures and particle concentrations are compared to experimental data from literature for model validation.

Atomistic reverse nonequilibrium molecular dynamics simulation of the viscosity of ionic liquid 1-n-butyl 3-methylimidazolium bis(trifluoromethylsulfonyl)imide [bmim][Tf2N]

2018 ◽  
Vol 20 (33) ◽  
pp. 21544-21551 ◽  
Author(s):  
Rouhollah Safinejad ◽  
Nargess Mehdipour ◽  
Hossein Eslami
Keyword(s):  
Molecular Dynamics ◽  
Ionic Liquid ◽  
Molecular Dynamics Simulation ◽  
Shear Viscosity ◽  
Room Temperature ◽  
Room Temperature Ionic Liquid ◽  
Dynamics Simulation ◽  
Nonequilibrium Molecular Dynamics ◽  
Temperature Range ◽  
Nonequilibrium Molecular Dynamics Simulation

The shear viscosity of room-temperature ionic liquid (IL) 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [bmim][Tf2N] is calculated over a temperature range 298–353 K, using the reverse nonequilibrium molecular dynamics simulation technique.

scholarly journals Rheological Behavior of Polymer Nanocomposites Filled with Spherical Nanoparticles: Insights from Molecular Dynamics Simulation

2021 ◽  
Author(s):  
Haoxiang Li ◽  
Haoyu WU ◽  
Wenfeng Zhang ◽  
Xiuying Zhao ◽  
Yangyang Gao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Polymer Nanocomposites ◽  
Shear Viscosity ◽  
Rheological Behavior ◽  
Molecular Level ◽  
Dynamics Simulation ◽  
Mean Square ◽  
Shear Rates ◽  
The Mean

<div><div>It is very urgent to understand the rheological behavior of polymer nanocomposites (PNCs) on the molecular level, which is very important for their processing and application. Thus, here the reverse nonequilibrium molecular dynamics simulation isemployed to explore it by tuning the nanoparticle (NP) concentration, the polymer-NPinteraction and the NP size. The shear viscosity (η~-m) exhibits a power law with theshear rate where m varies from 0.42 to 0.53 at high shear rates. By adopting the Carreau-Yasuda model, the obtained zero-shear viscosity gradually rises with increasing the NPconcentration, polymer-NP interaction or reducing the NP size. This is attributed to thestrong adsorption of chains by NPs and the formed network, which leads to the retarded dynamics. In addition, both the first and second normal stress differences also show power laws on the shear rates. The chains are gradually extended as the increase of shear rates, which is characterized by the mean-square end-to-end distance and the mean square radius of gyration. Especially, the evolution process of the NP network and the polymer- NP network is analyzed to deeply understand the shear thinning behavior. The number ofthe direct contact structure of NPs increases while the number of polymer-NP bridgedstructure is reduced. This is further proved by the increase of the formation probability of the NP network and the decrease of the polymer-NP interaction energy. Finally, the chain dynamics is found to be enhanced due to the shear flow. In summary, this work provides a further understanding on the mechanism of the shear thinning of PNCs on the molecular level. <br></div></div>

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