Prediction of methane PVT relations at high temperatures by a simplified virial equation of state

In order to meet the demand of describing the supercritical gas under high temperature and medium-high pressure conditions, such as in detonation circumstance, a simplified virial equation of state (EOS), named Han-Long (HL), is presented, which is based on Lennard-Jones potential function. One hundred and twelve sets of theoretical data for methane above 1000 K are calculated using HL EOS. We obtain that the volume average absolute deviation (AAD) is about 1% and the maximum error is 3.28%; this error is far lower than the calculation deviation of DMW (Duan-Moller-Weare) EOS and BS (Belonoshko-Saxena) EOS. The shockwave data of methane is also calculated by HL EOS and the AAD are less than 3%. Results show that HL EOS can well describe the thermodynamic state of CH4 at high temperatures.