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

T Ijichi and SI Tsuda and T Tokumasu and H Nagashima, MOLECULAR PHYSICS, 121 (2023).

DOI: 10.1080/00268976.2023.2192836

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 ABSTRACTR

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