scholarly journals Thermal transport during thin-film argon evaporation over nanostructured platinum surface: A molecular dynamics study

2018 ◽  
Vol 232 (2-3) ◽  
pp. 83-91
Author(s):  
Mohammad Nasim Hasan ◽  
Sheikh Mohammad Shavik ◽  
Kazi Fazle Rabbi ◽  
Khaled Mosharraf Mukut ◽  
Md. Muntasir Alam
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Thermal Transport ◽  
Molecular System ◽  
Dynamics Simulation ◽  
Sudden Increase ◽  
Nanostructured Surface ◽  
Surface Wetting ◽  
Platinum Surface ◽  
Fluid Interaction

Investigation of thermal transport characteristics of thin-film liquid evaporation over nanostructured surface has been conducted using molecular dynamics simulation with particular importance on the effects of the nanostructure configuration for different wall–fluid interaction strengths. The nanostructured surface considered herein comprises wall-through rectangular nanoposts placed over a flat wall. Both the substrate and the nanostructure are of platinum while argon is used as the evaporating liquid. Two different wall–fluid interaction strengths have been considered that essentially emulate both hydrophilic and hydrophobic wetting conditions for three different nanostructure configurations. The argon–platinum molecular system is first equilibrated at 90 K and then followed by a sudden increase in the wall temperature at 130 K that induces evaporation of argon laid over it. Comparative effectiveness of heat and mass transfer for different surface wetting conditions has been studied by calculating the wall heat flux and evaporative mass flux. The results obtained in this study show that heat transfer occurs more easily in cases of nanostructured surfaces than in case of flat surface. Difference in behavior of argon molecules during and after the evaporation process, that is, wall adsorption characteristics, has been found to depend on the surface wetting condition as well as on presence and configuration of nanostructure. A thermodynamic approach of energy balance shows reasonable agreement with the present molecular dynamics study.

Molecular Dynamics Simulation of Normal and Explosive Boiling on Nanostructured Surface

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
Hamid Reza Seyf ◽  
Yuwen Zhang
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Evaporation Rate ◽  
Solid Wall ◽  
Molecular System ◽  
Spherical Shape ◽  
Dynamics Simulation ◽  
Spherical Particles ◽  
Explosive Boiling ◽  
Higher Temperature

Molecular Dynamics (MD) simulation is carried out to investigate the normal and explosive boiling of thin film adsorbed on a metal substrate whose surface is structured by an array of nanoscale spherical particles. The molecular system is comprised of the liquid and vapor argon as well as a copper wall. The nanostructures have spherical shape with uniform diameters while the thickness of liquid film is constant. The effects of transvers and longitudinal distances as well as the diameter of nanoparticles are analyzed. The simulation is started from an initial configuration for three phases (liquid argon, vapor argon and solid wall); after equilibrating the system at 90 K, the wall is heated suddenly to a higher temperature that is well beyond the critical temperature of argon. Two different superheat degrees are selected: a moderately high temperature of 170 K for normal evaporation and much higher temperature 290 K for explosive boiling. By monitoring the space and time dependences of temperature and density as well as net evaporation rate, the normal and explosive boiling process on a flat surface with and without nanostructures are investigated. The results show that the nanostructure has significant effect on evaporation/boiling of thin film. The degrees of superheat and size of nanoparticles have significant effects on the trajectories of particles and net evaporation rate. For the cases with nanostructure, liquid responds very quickly and the number of evaporation molecules increases with increasing the size of particles from 1 to 2 nm while it decreases for d = 3 nm.

The Study on Young's Modulus of Multilayered Cu/Ni Multilayered Nano Thin Films by Molecular Dynamics Simulation

2014 ◽  
Vol 513-517 ◽  
pp. 113-116
Author(s):  
Jen Ching Huang ◽  
Fu Jen Cheng ◽  
Chun Song Yang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Strain Rate ◽  
Young’S Modulus ◽  
Potential Function ◽  
Dynamics Simulation ◽  
System Temperature ◽  
Simulation Results

The Youngs modulus of multilayered nanothin films is an important property. This paper focused to investigate the Youngs Modulus of Multilayered Ni/Cu Multilayered nanoThin Films under different condition by Molecular Dynamics Simulation. The NVT ensemble and COMPASS potential function were employed in the simulation. The multilayered nanothin film contained the Ni and Cu thin films in sequence. From simulation results, it is found that the Youngs modulus of Cu/Ni multilayered nanothin film is different at different lattice orientations, temperatures and strain rate. After experiments, it can be found that the Youngs modulus of multilayered nanothin film in the plane (100) is highest. As thickness of the thin film and system temperature rises, Youngs modulus of multilayered nanothin film is reduced instead. And, the strain rate increases, the Youngs modulus of Cu/Ni multilayered nanothin film will also increase.

The role of optical phonons in intermediate layer-mediated thermal transport across solid interfaces

2017 ◽  
Vol 19 (28) ◽  
pp. 18407-18415 ◽  
Author(s):  
Eungkyu Lee ◽  
Tengfei Luo
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Optical Phonon ◽  
Thermal Transport ◽  
Intermediate Layer ◽  
Dynamics Simulation ◽  
Optical Phonons ◽  
Spectral Matching

A study with molecular dynamics simulation shows that optical phonon vibrational spectral matching by an intermediate layer can significantly impact thermal transport across diatomic solid interfaces.

scholarly journals Thermal Transport in Graphene Oxide Films: Theoretical Analysis and Molecular Dynamics Simulation

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 285 ◽  
Author(s):  
Yi Yang ◽  
Dan Zhong ◽  
Yilun Liu ◽  
Donghui Meng ◽  
Lina Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Graphene Oxide ◽  
Molecular Dynamics Simulation ◽  
Thermal Transport ◽  
Oxide Films ◽  
Vacancy Defect ◽  
Transport Processes ◽  
Dynamics Simulation ◽  
Great Promise

As a derivative material of graphene, graphene oxide films hold great promise in thermal management devices. Based on the theory of Fourier formula, we deduce the analytical formula of the thermal conductivity of graphene oxide films. The interlaminar thermal property of graphene oxide films is studied using molecular dynamics simulation. The effect of vacancy defect on the thermal conductance of the interface is considered. The interfacial heat transfer efficiency of graphene oxide films strengthens with the increasing ratio of the vacancy defect. Based on the theoretical model and simulation results, we put forward an optimization model of the graphene oxide film. The optimal structure has the minimum overlap length and the maximum thermal conductivity. An estimated optimal overlap length for the GO (graphene-oxide) films with degree of oxidation 10% and density of vacancy defect 2% is 0.33 μm. Our results can provide effective guidance to the rationally designed defective microstructures on engineering thermal transport processes.

Sign in / Sign up

Export Citation Format

Share Document