Molecular Dynamics Simulation Of Supercritical State The Supercritical Argon

We mainly study the real gas equation of state under the supercritical state, perform themolecular dynamics simulation of supercritical argon at temperature of160K and170K,respectively. And then, we make virial correction for the ideal gas state equation using themethod of cluster expansion, to obtain the correction equation of real gas.The main works and conclusions are as follows:Firstly, by compairng the ideal gas state equation with simulation data curves, we findthat the two curvcs fit well when the pressure is less than2Mpa, whereas, when the pressure isover2MPa, the deviation of two curves increases with the increasing of pressure, for thedissatisfaction with the condition of the ideal gas for the pressure of2MPa. It also showedthat the simulation data are correct and valuable. Secondly, we make correction for the secondviiral coeiffcient of ideal gas state equation, compare it with the simulation data and ideal gasstate equation, respectively, to indicate that the three curves fit well, which manifests that thecorrection equation can express the properties of real gas state equation even when thepressure is low. And when the pressure is around5MPa，the correction curvc deviates far fromboth the simulation data and real gas state curve.Finally, it shows that, consideirng the third virial coeiffcient and with the pressure attainsa certain value, although the simulation data can not match the corrcction curve, for amutation affected by the cirtical point, the correction for real gas equation of state is moreaccurate than the correction only considering the sccond viiral coefficient, the attendance ofthe third viiral coefficient make the deviation between the corrcction viiral curve and real gascurve much smaller, both at the temperature of160K and170K, The correction equation withthe third virial coefifcient is much closer to real gas state equation both from microsimulationand from macroinfcrence.Above on, wc study some thermal properties of argon in supercritical state by the methodof molecular dynamics simulation, and analyze the real gas equation of state accurately, which is helpful to our further research in physics.