The evaluation of density and diffusion properties in hydrogen/oxygen mixture modelled by Lennard-Jones fluid

Abstract

This paper examines the satisfaction of the principle of corresponding states (PCS) on thepressure–density–temperature relation and the binary diffusion coefficient of hydrogen/oxygen mixture modelled as binary Lennard–Jones (LJ) fluid especially in a supercritical region. The hydrogen/oxygen mixture properties were computed by molecular dynamics simulation and compared with simulation results for a nitrogen/oxygen mixture as well as while using the Peng–Robinson (PR) equation of state (EOS) for both mixture types and a mono-component LJ-EOS. The Fuller–Schettler–Giddings model with the PR-EOS and Takahashi’s EOS were used for binary diffusion coefficient comparison. The pseudocritical point concept of a fluid mixture was applied for PCS reduction and PCS satisfaction was conducted over a wide temperature range above the pseudocritical pressure with changing hydrogen molar fraction. PCS satisfaction for hydrogen/oxygen mixture properties was confirmed at reduced temperature of 1.5 or above. At reduced temperature of 1.0 or below, the hydrogen/oxygen mixture properties disagree with those of the comparison mixture because phase separation occurs. We conclude that the properties of hydrogen/oxygen mixtures can be estimated using the pseudocritical point concept and the investigated EOSs based on the PCS in the supercritical region at reduced temperature of1.5 or above.

GRAPHICAL ABSTRACT

KEYWORDS:

• Thermodynamic property
• binary diffusion coefficient
• hydrogen/oxygen mixture
• Lennar-Jones fluid
• molecular dynamics method

Acknowledgments

Part of this simulation was performed on the Supercomputer of the Institute of Fluid Science.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Part of this work was supported by JSPS KAKENHI 22H01686 (principal investigator: Prof. Nobuyuki Tsuboi) and the Collaborative Research Project of the Institute of Fluid Science, Tohoku University.