Lennard-Jones equation of state

From SklogWiki
Jump to: navigation, search

The equation of state of the Lennard-Jones model.

Johnson, Zollweg and Gubbins[edit]

Johnson, Zollweg and Gubbins [1] proposed an equation of state based on 33 parameters within a modified Benedict, Webb and Rubin equation of state, which accurately reproduces the vapour-liquid equilibrium curve.

Kolafa and Nezbeda[edit]

The Kolafa and Nezbeda equation of state [2] provides us with the Helmholtz energy function: (Eq. 30):

A=A_{\mathrm{HS}} + \exp (-\gamma \rho^2) \rho T \Delta B_{2,{\mathrm{hBH}}} + \sum_{ij} C_{ij} T^{i/2} \rho^j

the compressibility factor (Eq. 31)

z \equiv \frac{P}{\rho T}= z_{\mathrm{HS}} +  \rho(1-2\gamma\rho^2) \exp (-\gamma \rho^2) \Delta B_{2,{\mathrm{hBH}}} + \sum_{ij} jC_{ij} T^{i/2-1} \rho^j

and the internal energy (Eq. 32)

U=
 {3(z_{\rm HS}-1)\over d_{\rm hBH}}\,
 {\partial d_{\rm hBH}\over \partial (1/T)}
 + \rho \exp(-\gamma\rho^2)\,{\partial \Delta B_{\rm2,hBH}\over\partial (1/T)}
 - \sum_{ij} \left({i\over2}-1\right) C_{ij}\, T^{i/2} \rho^j

On the following page is the FORTRAN code for the Kolafa and Nezbeda equation of state.

Ree[edit]

The Ree equation of state [3] is an extension of the earlier work of Hansen [4] in the high temperature region.

Boltachev and Baidakov[edit]

Boltachev and Baidakov have paid particular attention to including data from the metastable region [5].

Pieprzyk-Brańka-Maćkowiak and Heyes[edit]

The Pieprzyk-Brańka-Maćkowiak and Heyes equation of state [6] consists of a parameterisation of the modified Benedict, Webb and Rubin equation of state.

References[edit]

Related reading


40px-Stop hand nuvola.svg.png This page contains numerical values and/or equations. If you intend to use ANY of the numbers or equations found in SklogWiki in any way, you MUST take them from the original published article or book, and cite the relevant source accordingly.