Joule–Thomson Inversion Curves of Helium Isotopologues from Theoretical Virial Coefficients

Abstract

The present paper reports the full range Joule–Thomson inversion curves of two helium isotopologues, ⁴He and ³He, constructed by the density virial equation of state with state-of-the-art theoretical virial coefficients. The peak temperatures and the peak pressures were determined to be 20.45 K and 3.715 MPa for ⁴He, and 18.57 K and 2.456 MPa for ³He. The maximum inversion temperatures at zero pressure were determined to be 44.72 K for ⁴He and 38.80 K for ³He, which are identical with the expected values from the second virial coefficients. The present full range inversion curves were improved compared to the previous ones especially in their higher temperature branches, and hence they are the most reliable at the point in time.