This document is to a very large extent an excerpt from a paper published by the Techniques de l'Ingénieur [BE 8044]. Its purpose is to present some thermodynamics packages.

The thermodynamics packages are computer tools that calculate the thermodynamic state of a fluid in a wide range of its state variables. To do this, they use mathematical formulations of their properties, based on equations whose form and parameters have been adjusted or can be adjusted by comparison with experimental values ​​obtained by research laboratories and published in the literature or in databases. The main equations of state are adjusted by digital techniques, and differential equations of thermodynamics are used to infer the derived functions.

When the same formulation cannot provide sufficient accuracy throughout the range of the fluid domain, it is divided into several regions, each described by an appropriate formulation (liquid zones, vapor-liquid equilibrium zone, steam.. ) . At the boundaries of these regions, small differences in value may exist.

Available thermodynamics software tools fall into three broad categories:

• fluid property calculators, sometimes called property servers. They are distinguished by the number of fluids available, the accuracy of calculations, the independent variables accepted, the user-friendliness of the interface…

• component calculation tools are used to calculate unit operations (compression, expansion, combustion...) undergone by fluids. Not only do they incorporate fluid property calculators, but they can, by taking into account the characteristics of an industrial component (compressor isentropic or polytropic efficiency...), determine the final state of the fluid passing through;

• the third category of tools corresponds to generic modeling environments, which allow one to assemble component models to form complex systems or to solve large systems of equations

Most thermodynamics packages presented here belong to the first category.

Depending on cases, the software packages are general or are dedicated to a particular application. The former are generally more powerful, but they require from the user thermodynamics skills more developed than the latter, designed to meet a specific need.

It is important to note that the packages shown or mentioned here do not all have been tested by the author and their selection does not imply in any way that they meet the expectations of their users. He alone bears the responsibility of choosing a package: The information provided in this article are incomplete and purely indicative. It cannot be considered sufficient to base the selection of any tool for a particular application. It is also common that software versions evolve, and even some disappear. Those shown here were downloaded in March 2007.

We selected about twenty tools that appeared to be particularly interesting for the portal users, the main criteria being their potential (accuracy, and resolution capacity) and the conditions of access, including through the Internet, free software being obviously particularly attractive. All packages listed are available for Windows and in some cases for Mac OS or Unix.

The descriptions of the packages presented are generally based on their documentation. Due to lack of space, they are very basic and it only possible to demonstrate the use of tools by a small number of figures, often only one. Since they can capitalize in a form directly usable a considerable scientific and practical knowledge, we recommend to those interested to refer to the websites mentioned, where they can discover all their assets.

We will focus on three main types of software, the first two dealing with non-reactive environments, and the third allowing one calculate chemical reactions:

• generic tools for calculating phase equilibria of pure substances and mixtures

• preset equations of state tools dedicated to certain classes of applications

• combustion packages

The author thanks his thermodynamics colleagues who suggested him the selection of software packages listed in this page, including R. Carreras , D. Clodic , J.-N. Jaubert , X. Joulia , D. Marchio , P. Neveu and D. Richon