Real-gas effects in the expansibility factor for subsonic differential-pressure flowmeters at high pressure

Abstract

Real-gas corrections in the expansibility factor are expressed by an equation of state (EOS). In this paper a virial EOS is introduced, with low-order virial coefficients calculated from a cubic EOS. The approach is composition-independent. EOS-dependent cancellations between real-gas effects are revealed. The current Intl. Organization for Standardization (ISO) standard is not always reliable for high-accuracy orifice measurements of gases with arbitrary composition.