Mie 16–6 force field predicts viscosity with faster-than-exponential pressure dependence for 2,2,4-trimethylhexane

Richard A. Messerly, Michelle C. Anderson, S. Mostafa Razavi, J. Richard Elliott

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

In response to the 10th Industrial Fluid Properties Simulation Challenge, we report viscosity (η) estimates obtained with equilibrium molecular dynamics for 2,2,4-trimethylhexane at 293 K and over a range of pressures (P) from 0.1 MPa to 1000 MPa. The Mie Potentials for Phase Equilibria (MiPPE) force field is utilized in this study, as a previous study demonstrated that it provides reliable estimates of η with respect to P. Whereas most studies report only the uncertainties associated with random fluctuations in the simulation output and subsequent data analysis, we investigate the effect of uncertainties arising from the force field non-bonded and torsional parameters. The pressure-viscosity coefficient as a function of pressure is reported for several different empirical models, namely, McEwen-Paluch, Roelands, Roelands-Modified, and Barus. Although the uncertainties increase substantially with increasing pressure, cross-validation model selection provides quantitative evidence supporting faster-than-exponential, a.k.a. super-Arrhenius, behavior with an apparent inflection point in a log10(η)-P plot around 200 MPa. Near-quantitative agreement between simulation results and new experimental data is achieved for P≤600 MPa, followed by significant over prediction at higher pressures.

Original languageEnglish
Pages (from-to)76-85
Number of pages10
JournalFluid Phase Equilibria
Volume495
DOIs
StatePublished - Sep 1 2019
Externally publishedYes

Funding

This research was performed while Richard A. Messerly held a National Research Council (NRC) Postdoctoral Research Associateship at NIST and while Michelle C. Anderson held a Summer Undergraduate Research Fellowship (SURF) position at NIST.

Keywords

  • Green-Kubo
  • Industrial Fluid Properties Simulation Challenge
  • Molecular dynamics simulation
  • Pressure-viscosity coefficient
  • Uncertainty quantification

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