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

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.