scholarly journals Biasing the Center of Charge in Molecular Dynamics Simulations with Empirical Valence Bond Models: Free Energetics of an Excess Proton in a Water Droplet

2008 ◽  
Vol 112 (28) ◽  
pp. 8425-8425
Author(s):  
Jürgen Köfinger ◽  
Christoph Dellago
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Water Droplet ◽  
Valence Bond ◽  
Empirical Valence Bond ◽  
Dynamics Simulations

scholarly journals Achilles: A Tool for Contact Angle Estimation from Molecular Dynamics Simulations

2021 ◽  
Author(s):  
Sumith Yesudasan
Keyword(s):  
Molecular Dynamics ◽  
Contact Angle ◽  
Molecular Dynamics Simulations ◽  
Water Droplet ◽  
Dynamics Simulation ◽  
Hydrophilic Surfaces ◽  
Interfacial Physics ◽  
Droplet Liquid ◽  
Dynamics Simulations ◽  
Molecular Dynamics Results

In this work, a tool for estimating the contact angle from the molecular dynamics simulations is developed and presented. The tool (Achilles) can detect water droplet on hydrophobic and hydrophilic surfaces. The tool can reconstruct the droplets broken across the periodic boundaries. Further a neighbor density based accurate filter is used to find the droplet liquid vapor interface and a circle is fitted using it after removing the dense layers of water next to solid surface. This fitted circle is solved for contact angle and results are outputted in the form of graphical images and text. The entire content of the internal computations of the tool is broken down into 4 phases and users can monitor the outcomes at every phase through output images. The tool is tested using sample molecular dynamics results of water droplet on hydrophobic and hydrophilic surfaces. We believe this tool can be a good addition to the molecular dynamics simulation community who work on the interfacial physics, droplet evaporation, super hydrophobic surfaces, and wettability etc.

scholarly journals Permeation of Water Nanodroplets on Carbon Nanotubes Forests

MRS Advances ◽  
2017 ◽  
Vol 2 (02) ◽  
pp. 123-128
Author(s):  
Ygor M. Jaques ◽  
Douglas S. Galvao
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Molecular Dynamics Simulations ◽  
Pore Size ◽  
Water Droplet ◽  
Nanotube Arrays ◽  
Carbon Nanotube Arrays ◽  
Tube Arrays ◽  
Dynamics Simulations

ABSTRACT Fully atomistic molecular dynamics simulations were carried out to investigate how a liquid-like water droplet behaves when into contact with a nanopore formed by carbon nanotube arrays. We have considered different tube arrays, varying the spacing between them, as well as, different chemical functionalizations on the uncapped nanotubes. Our results show that simple functionalizations (for instance, hydrogen ones) allow tuning up the wetting surface properties increasing the permeation of liquid inside the nanopore. For functionalizations that increase the surface hydrophilicity, even when the pore size is significantly increased the droplet remains at the surface without tube permeation.

Molecular Dynamics Simulations of Nanoscale Water Jet

2008 ◽  
Author(s):  
Jau-Wen Lin ◽  
Shu-Xian Chu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Flow Rate ◽  
Formation Process ◽  
Water Droplet ◽  
Droplet Formation ◽  
Droplet Shape ◽  
Physical Insight ◽  
Dynamics Simulations ◽  
Nozzle Opening

This paper represents molecular dynamics simulations of pressurized ejection of water nanojet and water droplet formation process. In the simulations, the effects of nozzle opening size, pressing force and temperature on the nano water droplet formation are investigated. The relation of droplet shape with flow rate at the nozzle opening is also discussed. The data from these simulations are analyzed to get a physical insight view of nano water droplet formation.

scholarly journals Molecular mechanisms responsible for hydrate anti-agglomerant performance

2016 ◽  
Vol 18 (36) ◽  
pp. 24859-24871 ◽  
Author(s):  
Anh Phan ◽  
Tai Bui ◽  
Erick Acosta ◽  
Pushkala Krishnamurthy ◽  
Alberto Striolo
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Water Droplet ◽  
Molecular Mechanisms ◽  
Hydrocarbon Mixture ◽  
Dynamics Simulations

Steered and equilibrium molecular dynamics simulations were employed to study the coalescence of a sI hydrate particle and a water droplet within a hydrocarbon mixture.

A GEOCHEMISTRY-ORIENTED WORKFLOW FOR WETTABILITY ASSESSMENT AT RESERVOIR CONDITION USING MOLECULAR DYNAMICS SIMULATIONS

2021 ◽  
Author(s):  
Isa Silveira de Araujo ◽  
◽  
Archana Jagadisan ◽  
Zoya Heidari ◽  
◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Contact Angle ◽  
Molecular Dynamics Simulations ◽  
Water Droplet ◽  
Contact Angles ◽  
Fluid Distribution ◽  
Reservoir Temperature ◽  
Reservoir Condition ◽  
Dynamics Simulations ◽  
The Impact

Reliable quantification of wettability is critical in assessment of fluid distribution, capillary pressure, relative permeability, and flow properties of fluids in reservoirs. Wettability of reservoirs can be affected by chemical composition of rock-fluid system, salinity, and reservoir temperature. Experimental assessment of wettability under reservoir conditions, while gaining control on the aforementioned parameters, may be tedious and challenging. Several published researches have used experimental studies to focus on determining the impact of individual factors on wettability of rock. However, studies on the combined effects of these factors are limited, although critical, for better understanding of wettability of hydrocarbon reservoirs. In this paper we introduce a workflow for assessment of wettability of rocks at reservoir condition using molecular dynamics (MD) simulations. The outcomes include (i) quantifying the wettability of pure minerals, (ii) quantifying the impact of reservoir temperature on wettability of pure mineral. The inputs to the simulation include molecules of pure minerals (quartz, calcite, albite) packed in a cubical simulation box. The molecules are condensed to form a flat surface. Subsequently, water and oil (hexane) molecules are placed on the surface of the mineral. We then perform simulations with constant number of particles, temperature and volume (NVT) on the system till equilibrium is reached. At equilibrium, the contact angle formed by the water droplet is measured. Contact angle is simulated for temperature conditions in the range of 300 to 380 K. The results showed that the contact angle between water-mineral for quartz, calcite, and albite at room temperature (300 K) ranges from 30º to 45º, indicating that the surface of these minerals is hydrophilic, with different degrees of hydrophilicity. This information is essential for reliable fluid flow simulations, which are often overlooked in conventional approaches. We also found that the temperature has a measurable impact on the contact angles formed by water droplet. We found that increase in temperature from 300 to 380 K decreases the contact angles by approximately 30% on quartz surfaces, 20% on albite surfaces, and 24% on calcite surfaces. The results for the hexane-mineral system show that the hexane behaved similarly in the three minerals surface. A thin film of hexane is formed at the surface corresponding to a contact angle of 0º. The method introduced in this paper has application for reliable evaluation of wettability at any reservoir of interest by knowing the molecular structure of clay and non-clay minerals as well as fluid content. Moreover, the challenges of wettability determination under high temperature and pressure conditions can also be efficiently addressed by using molecular dynamics simulations.

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