Mutual diffusion coefficients of heptane isomers in nitrogen: A molecular dynamics study

Chae, Kyungchan; Violi, Angela

doi:10.1063/1.3512918

Cited by 36 publications

(16 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, for the case of infinite dilution, the expression for mutual mass diffusivity conveniently reduces to the solute's selfdiffusivity. Note that for numerical comparison in some cases, we also calculated the diffusion coefficients with use of the Green-Kubo method [5].…”

Section: Description Of the Simulated Systemmentioning

confidence: 99%

“…Determining fluid diffusion properties in the supercritical regime is challenging from the experimental standpoint [1][2][3][4], which often reduces the practicality of direct measurement. Current analytical calculations based on kinetic theory can provide an adequate description of the self-diffusivity of pure fluids, but yield significantly less accurate results for mixtures [5]. As a result, molecular dynamics (MD) simulations have been utilized to determine the mutual mass diffusivity of mixtures (as well as pure fluids) with relative success [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Current analytical calculations based on kinetic theory can provide an adequate description of the self-diffusivity of pure fluids, but yield significantly less accurate results for mixtures [5]. As a result, molecular dynamics (MD) simulations have been utilized to determine the mutual mass diffusivity of mixtures (as well as pure fluids) with relative success [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mass diffusion of organic fluids : a molecular dynamics perspective

Smolyanitsky¹,

Kazakov²,

Bruno³

et al. 2013

View full text Add to dashboard Cite

The Optimized Potential for Liquid Simulation All-Atom (OPLS-AA) forcefield, a wellestablished interaction potential, within the MD framework was used to determine self-and mutual diffusivity of several fluids, in the high-pressure and near-and supercritical regimes. The test fluids were benzene, heptane and carbon dioxide. The Green-Kubo method of calculating mass diffusivity yielded considerably overestimated values of self-diffusivity; better results were obtained with use of the Stokes-Einstein method. In addition, a number of relatively significant problems with the default OPLS-AA parameterization were identified. There exist ranges of pressure and temperatures, in which the results for the selected pure fluids show good agreement with experiment, and thus reparameterization of OPLS-AA may not be required. However, the results for mixtures all show significant deviation from experiment. Based on the observed results, the current predictive power of OPLS-AA for mass diffusivity of the fluids in question is not satisfactory. We are therefore convinced that a systematic reparameterization of OPLS-AA both in terms of the intermolecular (van der Waals, electrostatic) and intramolecular (bonding) interactions is needed to increase its accuracy. In addition, OPLS-AA may not be generally appropriate for the gaseous state and therefore near-critical systems may benefit from using a different forcefield.

show abstract

Section: Description Of the Simulated Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mass diffusion of organic fluids : a molecular dynamics perspective

Smolyanitsky¹,

Kazakov²,

Bruno³

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Diffusion coefficients are calculated using the method of Wilke and Lee [14] with Lennard Jones parameter extracted from Hirschfelder et al [15] for n-pentane and nitrogen. For nheptane the Lennard Jones parameter are listed in Chea and Violi [16]. Furthermore, the saturation pressure of the liquid in the vapour phase is corrected by the binary mixture composition in equilibrium using an enhancement factor as explained by Luijten [17].…”

Section: Characterization Of the Droplet Surface Temperaturementioning

confidence: 99%

Experimental Investigation of Droplet Injections in the Vicinity of the Critical Point: A comparison of different model approaches

Steinhausen

Lamanna

Stierle

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

View full text Add to dashboard Cite

The disintegration process of liquid fuel within combustion chambers is one of the most important parameters for efficient and stable combustion. Especially for high pressures exceeding the critical value of the injected fluids the mixing processes are not fully understood yet. Recently, different theoretical macroscopic models have been introduced to understand breakdown of the classical two phase regime and predict the transition from evaporation to a diffuse-mixing process. In order to gain deeper insight into the physical processes of this transition, a parametric study of free-falling n-pentane droplets in an inert nitrogen atmosphere is presented. Atmospheric conditions varied systematically from sub-to supercritical values with respect to the fluid properties. An overlay of a diffuse lighted image with a shadowgram directly in the optical setup (front lighted shadowgraphy) was applied to simultaneously detect the presence of a material surface of the droplet as well as changes in density gradients in the surrounding atmosphere. The experimental investigation illustrates, that the presence of a material surface cannot be shown by a direct shadowgram. However, reflections and refractions caused by diffuse ambient illumination are able to indicate the presence of a material surface. In case of the supercritical droplet injections in this study, front lighted shadowgraphy clearly revealed the presence of a material surface, even when the pre-heated droplets are released into a supercritical atmosphere. This detection of the droplet interface indicates, that the droplet remains subcritical in the region of interest, even though it is injected into a supercritical atmosphere. Based on the adiabatic mixing assumption recent Raman-scattering results in the wake of the droplet are re-evaluated to compute the temperature distribution. Presented experimental findings as well as the re-evaluation of recent Raman scattering results are compared to thermodynamic models to predict the onset of diffuse-mixing and supercritical disintegration of the droplet. Additionally, a one dimensional evaporation model is used to evaluate the validity of the adiabatic mixing assumption in the estimation of the droplet temperature. The presented findings contribute to the understanding of recent theoretical models for prediction of spray and droplet disintegration and the onset of diffuse-mixing processes. Keywords Front lighted Shadowgraphy, Raman-scattering, Supercritical fluid injection IntroductionThe disintegration process of liquid droplets in a high pressure and high temperature environment is one of the most important parameters for stable and efficient combustion. Therefore, the behaviour of droplets in such an environment has long been a matter of analytical, numerical and experimental investigation. Especially the transition process from a two phase behaviour of the droplet or jet to a diffusion dominated mixture is not yet well understood. Recently, three different models predicting the onset of this diffuse-mixing...

show abstract

“…Considering that the LJ potential parameters used to model the binary diffusion coefficient are estimated customarily from measured viscosity [38][39][40][41], there is no theoretical reason to believe that the use of the LJ potential would lead to adequate predictions for gas diffusivity. Recent molecular dynamics evidence indeed suggests that the spherical potential assumption can be inaccurate [43,44].…”

Section: Introductionmentioning

confidence: 99%

Drag force and transport property of a small cylinder in free molecule flow: A gas-kinetic theory analysis

Liu

Wang

2016

Phys. Rev. E

View full text Add to dashboard Cite

Analytical expressions are derived for aerodynamic drag force on small cylinders in the free molecule flow using the gas kinetic theory. The derivation considers the effect of intermolecular interactions between the cylinder and gas media. Two limiting collision models, specular and diffuse scattering, are investigated in two limiting cylinder orientations with respect to the drift velocity. The earlier solution of Dahneke (B. E. Dahneke, Journal of Aerosol Science 4, 147, 1973) is shown to be a special case of the current expressions in the rigid-body limit of collision.Drag force expressions are obtained for cylinders that undergo Brownian rotation and for those that align with the drift velocity. The validity of the theoretical expressions is tested against experimental mobility data available for carbon nanotubes.

show abstract

Mutual diffusion coefficients of heptane isomers in nitrogen: A molecular dynamics study

Cited by 36 publications

References 44 publications

Mass diffusion of organic fluids : a molecular dynamics perspective

Mass diffusion of organic fluids : a molecular dynamics perspective

Experimental Investigation of Droplet Injections in the Vicinity of the Critical Point: A comparison of different model approaches

Drag force and transport property of a small cylinder in free molecule flow: A gas-kinetic theory analysis

Contact Info

Product

Resources

About