Prediction of the Joule-Thomson inversion curve of air from cubic equations of state

摘要

A modified van der Waals equation of state recommended in the literature for improved prediction of the inversion curve of air is shown to be thermodynamically inconsistent, giving large errors in the critical and two-phase regions. An alternative procedure is presented by means of which the cohesion function of any cubic equation of state can be adjusted to give arbitrarily accurate representation of an experimental inversion curve. New versions of the van der Waals, Redlich-Kwong and Peng-Robinson equations of state are developed based on experimental inversion data of air, and are shown to give better inversion predictions than more complex, multiparameter noncubic equations of state. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 23]