Helmholtz energy translations for common cubic equations of state for use in one-fluid and multi- fluid mixture models

Published

June 20, 2016

Author(s)

Ian H. Bell, Andreas Jaeger

Abstract

Comprehensive and generalized derivations have been presented for the treatment of the residual part of the Helmholtz energy which arises from the transformation of several common cubic equations of state (Soave-Redlich-Kwong, Peng-Robinson and others of a similar formulation). These translations allow for the use of simple cubic equations of state in the complex multi- fluid models employed in the state-of-the-art thermophysical property libraries. Thus fluids (or mixtures) for which no accurate model exists in literature can be modeled with a relatively small set of fluid property data. Composition derivatives have been calculated for the cases where the last mole fraction xN is either an independent or dependent variable. A comprehensive and one-to-one C++ translation of the analysis presented here is provided in the supplementary information. Additional validation data and information about the computer algebra tools used to carry out the intermediate derivatives can be found in the supplementary information.

Citation

Journal of Research (NIST JRES) -

Volume

121

NIST Pub Series

Journal of Research (NIST JRES)

Pub Type

NIST Pubs

Download Paper

https://doi.org/10.6028/jres.121.011

Keywords

cubic equations of state, Helmholtz energy, multi-fluid models

Citation

Bell, I. and Jaeger, A. (2016), Helmholtz energy translations for common cubic equations of state for use in one-fluid and multi- fluid mixture models, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/jres.121.011 (Accessed October 13, 2024)