One-dimensional hard rod fluid in a disordered porous medium: scaled particle theory

TL;DR

This paper extends the scaled particle theory to analyze thermodynamic properties of a one-dimensional hard rod fluid in disordered porous media, introducing new approximations and verifying accuracy with Monte Carlo simulations.

Contribution

The study develops an extended SPT2 approach with new porosity considerations and analytical expressions for thermodynamic properties in disordered porous media.

Findings

The new porosity concept improves the accuracy of thermodynamic predictions.

Analytical expressions match Monte Carlo simulation results at high fluid densities.

The extended theory outperforms previous models in describing hard rod fluids in porous media.

Abstract

The scaled particle theory is applied to a description of thermodynamic properties of one-dimensional hard rod fluid in disordered porous media. To this end, we extended the SPT2 approach, which had been developed previously. Analytical expressions are obtained for the chemical potential and pressure of a hard-rod fluid in hard rod and overlapping hard rod matrices. A series of new approximations for SPT2 are proposed. It is shown that apart from two well known porosities such as geometrical porosity and specific probe particle porosity, a new type of porosity defined by the maximum value of packing fraction of fluid particles in porous medium should be taken into account. The grand canonical Monte-Carlo simulations are performed to verify the accuracy of the SPT2 approach in combination with the new approximations. It is observed that the theoretical description proposed in this study essentially improves the results up to the highest values of fluid densities.