Study on Vapor−Liquid Equilibria and Surface Tensions for Nonpolar Fluids by Renormalization Group Theory and Density Gradient Theory

2006 ◽  
Vol 110 (39) ◽  
pp. 19575-19581 ◽  
Author(s):  
Dong Fu
Keyword(s):  
Renormalization Group ◽  
Group Theory ◽  
Density Gradient ◽  
Gradient Theory ◽  
Renormalization Group Theory ◽  
Surface Tensions ◽  
Nonpolar Fluids ◽  
Density Gradient Theory ◽  
Vapor Liquid Equilibria ◽  
Vapor Liquid

scholarly journals Vapor−Liquid Interface of the Lennard-Jones Truncated and Shifted Fluid: Comparison of Molecular Simulation, Density Gradient Theory, and Density Functional Theory

2021 ◽  
Author(s):  
Simon Stephan ◽  
Jinlu Liu ◽  
Kai Langenbach ◽  
Walter G. Chapman ◽  
Hans Hasse
Keyword(s):  
Density Functional Theory ◽  
Density Gradient ◽  
Density Functional ◽  
Computer Experiments ◽  
Liquid Interface ◽  
Gradient Theory ◽  
Functional Theory ◽  
Lennard Jones ◽  
Density Gradient Theory ◽  
Vapor Liquid

The vapor-liquid interface of the Lennard-Jones truncated and shifted (LTJS) fluid with a cut-off radius of 2.5 σ is investigated for temperatures covering the range between the triple point and the critical point. Three different approaches to model the vapor-liquid interface are used: molecular dynamics (MD) simulations, density gradient theory (DGT) and density functional theory (DFT). The surface tension, pressure and density profiles, including the oscillatory layering structure of the fluid at the interface, are investigated. The PeTS (Perturbed truncated and shifted) equation of state and PeTS-i functional, based on perturbation theory, are used to calculate the Helmholtz free energy in the DGT and DFT approach. They are consistent with the LJTS force field model. Overall, both DGT and DFT describe the results from computer experiments well. An oscillatory layering structure is found in MD and DFT.

scholarly journals Vapor-liquid interfacial properties of the system cyclohexane + CO2: Experiments, molecular simulation and density gradient theory

2021 ◽  
Author(s):  
Simon Stephan ◽  
Stefan Becker ◽  
Kai Langenbach ◽  
Hans Hasse
Keyword(s):  
Density Gradient ◽  
Md Simulation ◽  
Interfacial Properties ◽  
Gradient Theory ◽  
Pendant Drop ◽  
Pure Substances ◽  
Density Gradient Theory ◽  
Relative Adsorption ◽  
Good Agreement ◽  
Vapor Liquid

Properties of the vapor-liquid interface of the binary mixture cyclohexane + CO2 as well as for the two pure substances are reported. The data were obtained from pendant drop experiments (Exp), molecular dynamics (MD) simulation, and density gradient theory (DGT) in combination with the PCP-SAFT equation of state. The following interfacial properties were studied: surface tension (Exp, MD, DGT), relative adsorption (Exp, MD, DGT), enrichment (MD, DGT), and interfacial thickness (MD, DGT). The measurements were carried out at temperatures between 303.15 K and 373.15 K and pressures up to 6 MPa. Furthermore, bulk VLE properties were computed by MD and PCP-SAFT and compared to experimental data from the literature. Data from experiment, MD, and DGT were found to be in good agreement throughout.

Sign in / Sign up

Export Citation Format

Share Document