Redlich Kwong EOS in FPROPS

This article is about planned development or proposed functionality. Comments welcome.

Work on this continues as part of GSoC 2011 (Richard Towers). See also FPROPS, PengRobinson EOS in FPROPS.

Overview

The Redlich-Kwong equation of state is one of several cubic equations of state that FPROPS aims to implement in the future. In its basic form it relates pressure to temperature and relative volume:

<math> \begin{align} P=\frac{RT}{V-b}-\frac{a}{V(V+b)} \end{align} </math>

Other thermodynamic properties can be calculated from the departure functions:

<math> \begin{align} A-A^{0}=-RT\ln\frac{V-b}{V}-\frac{a}{b}\ln\frac{V+b}{V}-RT\ln\frac{V}{V^{0}} \end{align} </math>

<math> \begin{align} S-S^{0}=R\ln\frac{V-b}{V}-\frac{a}{2bT}\ln\frac{V+b}{V}+R\ln\frac{V}{V^{0}} \end{align} </math>

<math> \begin{align} H-H^{0}=\frac{bRT}{V-b}-\frac{a}{V+b}-\frac{3a}{2b}\ln\frac{V+b}{V} \end{align} </math>

<math> \begin{align} U-U^{0}=-\frac{3a}{2b}\ln\frac{V+b}{V} \end{align} </math>

<math> \begin{align} G-G^{0}=\frac{bRT}{V-b}-\frac{a}{V+b}-RT\ln\frac{V-b}{V}-\frac{a}{b}\ln\frac{V+b}{V}-RT\ln\frac{V}{V^{0}} \end{align} </math>

<math> \begin{align} \ln\frac{f}{P}=\frac{b}{V-b}-\frac{a}{RT(V+b)}-\ln\frac{V-b}{V}-\frac{a}{bRT}\ln\frac{V+b}{V}-\ln\left(\frac{V}{V-b}-\frac{a}{RT(V+b)}\right) \end{align} </math>