scholarly journals Preference Parameters for the Calculation of Thermal Conductivity by Multiparticle Collision Dynamics

Entropy ◽  
2021 ◽  
Vol 23 (10) ◽  
pp. 1325
Author(s):  
Ruijin Wang ◽  
Zhen Zhang ◽  
Long Li ◽  
Zefei Zhu
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Liquid Argon ◽  
Coarse Grained ◽  
Collision Dynamics ◽  
Small Systems ◽  
Multiparticle Collision Dynamics ◽  
Calculation Results ◽  
Selection Of

Calculation of the thermal conductivity of nanofluids by molecular dynamics (MD) is very common. Regrettably, general MD can only be employed to simulate small systems due to the huge computation workload. Instead, the computation workload can be considerably reduced due to the coarse-grained fluid when multiparticle collision dynamics (MPCD) is employed. Hence, such a method can be utilized to simulate a larger system. However, the selection of relevant parameters of MPCD noticeably influences the calculation results. To this end, parameterization investigations for various bin sizes, number densities, time-steps, rotation angles and temperatures are carried out, and the influence of these parameters on the calculation of thermal conductivity are analyzed. Finally, the calculations of thermal conductivity for liquid argon, water and Cu-water nanofluid are performed, and the errors compared to the theoretical values are 3.4%, 1.5% and 1.2%, respectively. This proves that the method proposed in the present work for calculating the thermal conductivity of nanofluids is applicable.

Thermal Conductivity Computation of Nanofluids by Equilibrium Molecular Dynamics Simulation: Nanoparticle Loading and Temperature Effect

2007 ◽  
Vol 1022 ◽  
Author(s):  
Suranjan Sarkar ◽  
R. Panneer Selvam
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Effective Thermal Conductivity ◽  
Copper Nanoparticles ◽  
Base Fluid ◽  
Liquid Argon ◽  
Dynamics Simulation ◽  
System Temperature ◽  
Solid Copper

AbstractA model nanofluid system of copper nanoparticles in argon base fluid was successfully modeled by molecular dynamics simulation. The interatomic interactions between solid copper nanoparticles, base liquid argon atoms and between solid copper and liquid argon were modeled by Lennard Jones potential with appropriate parameters. The effective thermal conductivity of the nanofluids was calculated through Green Kubo method in equilibrium molecular dynamics simulation for varying nanoparticle concentrations and for varying system temperatures. Thermal conductivity of the basefluid was also calculated for comparison. This study showed that effective thermal conductivity of nanofluids is much higher than that of the base fluid and found to increase with increased nanoparticle concentration and system temperature. Through molecular dynamics calculation of mean square displacements for basefluid, nanofluid and its components, we suggested that the increased movement of liquid atoms in the presence of nanoparticle was probable mechanism for higher thermal conductivity of nanofluids.

Mesoscale methods

2017 ◽  
Author(s):  
Michael P. Allen ◽  
Dominic J. Tildesley
Keyword(s):  
Large Scale ◽  
Equations Of Motion ◽  
Dissipative Particle Dynamics ◽  
Coarse Graining ◽  
Coarse Grained ◽  
Collision Dynamics ◽  
Force Matching ◽  
Multiparticle Collision Dynamics ◽  
Long Time ◽  
Boltzmann Method

Coarse-graining is an increasingly commonplace approach to study, as economically as possible, large-scale, and long-time phenomena. This chapter covers the main methods. Brownian and Langevin dynamics are introduced, with practical details of the solution of the modified equations of motion. Several techniques which aim to bridge the gap to the hydrodynamic regime are described: these include dissipative particle dynamics, multiparticle collision dynamics, and the lattice Boltzmann method. Several examples of program code are provided. In the last part of the chapter, the derivation of a coarse-grained potential from an atomistic one is considered using force-matching and structure-matching, and the limitations of these approaches are discussed.

Molecular Dynamics Prediction of the Thermal Conductivity of Si/Ge Superlattices

2007 ◽  
Author(s):  
E. S. Landry ◽  
A. J. H. McGaughey ◽  
M. I. Hussein
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Direct Method ◽  
Proper Selection ◽  
Dynamics Simulations ◽  
Weber Potential ◽  
Selection Of ◽  
Non Equilibrium

Molecular dynamics simulations and the non-equilibrium direct method are used to predict the thermal conductivity of a Si/Ge superlattice modeled by the Stillinger-Weber potential at a temperature of 300 K. We focus on the methodology of making the thermal conductivity prediction (limited effort has been made to model Si/Ge nanocomposites in the literature) and find that proper selection of the size and composition of the thermal reservoirs is important.

Equilibrium Molecular Dynamics Simulation Study on the Effect of Nanoparticle Loading and Size on Thermal Conductivity of Nanofluids

2007 ◽  
Author(s):  
R. Panneer Selvam ◽  
Suranjan Sarkar
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Copper Nanoparticles ◽  
Thermal Conduction ◽  
Base Fluid ◽  
Liquid Argon ◽  
Dynamics Simulation ◽  
Solid Copper ◽  
Thermal Conductivities

Nanofluids have been proposed as a route for surpassing the performance of currently available heat transfer liquids for better thermal management needed in many diverse industries and research laboratories. Recent experiments on nanofluids have indicated a significant increase in thermal conductivity with 0.5 to 2% of nanoparticle loading in comparison to that of the base fluid. But the extent of thermal conductivity enhancement sometimes greatly exceeds the predictions of well established classical theories like Maxwell and Hamilton Crosser theory. In addition to that, these classical theories can not explain the temperature and nanoparticle size dependency of nanofluid thermal conductivity. Atomistic simulation like molecular dynamics simulation can be a very helpful tool to model the enhanced nanoscale thermal conduction and predict thermal conductivities in different situations. In this study a model nanofluid system of copper nanoparticles in argon base fluid is successfully modeled by equilibrium molecular dynamics simulation in NVT ensemble and thermal conductivities of base fluid and nanofluids are computed using Green Kubo method. The interatomic interactions between solid copper nanoparticles, base liquid argon atoms and between solid copper and liquid argon are modeled by Lennard Jones potential with appropriate parameters. For different volume fractions of nanoparticle loading, the thermal conductivities are calculated. The nanoparticle size effects on thermal conductivities of nanofluids are also systematically studied. This study indicates the usefulness of MD simulation to calculate thermal conductivity of nanofluid and explore the higher thermal conduction in molecular level.

scholarly journals Coarse-Grained Models Reveal Functional Dynamics – II. Molecular Dynamics Simulation at the Coarse-Grained Level – Theories and Biological Applications

2008 ◽  
Vol 2 ◽  
pp. BBI.S459 ◽  
Author(s):  
Choon-Peng Chng ◽  
Lee-Wei Yang
Keyword(s):  
Molecular Dynamics ◽  
Molecular Conformation ◽  
Conformational Dynamics ◽  
Dynamics Simulation ◽  
Coarse Grained ◽  
Time Step ◽  
Effective Potentials ◽  
Functional Dynamics ◽  
Indispensable Tool ◽  
Selection Of

Molecular dynamics (MD) simulation has remained the most indispensable tool in studying equilibrium/non-equilibrium conformational dynamics since its advent 30 years ago. With advances in spectroscopy accompanying solved biocomplexes in growing sizes, sampling their dynamics that occur at biologically interesting spatial/temporal scales becomes computationally intractable; this motivated the use of coarse-grained (CG) approaches. CG-MD models are used to study folding and conformational transitions in reduced resolution and can employ enlarged time steps due to the a bsence of some of the fastest motions in the system. The Boltzmann-Inversion technique, heavily used in parameterizing these models, provides a smoothed-out effective potential on which molecular conformation evolves at a faster pace thus stretching simulations into tens of microseconds. As a result, a complete catalytic cycle of HIV-1 protease or the assembly of lipid-protein mixtures could be investigated by CG-MD to gain biological insights. In this review, we survey the theories developed in recent years, which are categorized into Folding-based and Molecular-Mechanics-based. In addition, physical bases in the selection of CG beads/time-step, the choice of effective potentials, representation of solvent, and restoration of molecular representations back to their atomic details are systematically discussed.

scholarly journals Origin and structure of liquid crystalline Blue Phase III

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tanay Paul ◽  
Jayashree Saha
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Pair Interaction ◽  
Dynamics Simulation ◽  
Phase Iii ◽  
Coarse Grained ◽  
Anisotropic Liquid ◽  
Blue Phase ◽  
Selection Of

Abstract We report here an off-lattice NVT molecular dynamics simulation study of a system of polar chiral ellipsoidal molecules, which spontaneously exhibits Blue Phase III (BPIII), considering coarse-grained attractive-repulsive pair interaction appropriate for anisotropic liquid crystal mesogens. We have observed that suitable selection of chiral and dipolar strengths not only gives rise to thermodynamically stable BPIII but novel Smectic and Bilayered BPIII as well. Further, we have demonstrated that the occurrence of BPIII and its layered counterparts depend crucially on molecular elongation.

The effect of hydrodynamic interactions on nanoparticle diffusion in polymer solutions: a multiparticle collision dynamics study

Soft Matter ◽  
2017 ◽  
Vol 13 (45) ◽  
pp. 8625-8635 ◽  
Author(s):  
Anpu Chen ◽  
Nanrong Zhao ◽  
Zhonghuai Hou
Keyword(s):  
Molecular Dynamics ◽  
Polymer Solutions ◽  
Md Simulations ◽  
Simulation Method ◽  
Hydrodynamic Interactions ◽  
Collision Dynamics ◽  
Mesoscale Simulation ◽  
Multiparticle Collision Dynamics ◽  
Nanoparticle Diffusion

The diffusion of nanoparticles (NPs) in polymer solutions is studied by a combination of a mesoscale simulation method, multiparticle collision dynamics (MPCD), and molecular dynamics (MD) simulations.

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