The average absolute relative deviation (AARD) was observed to be between 1% and 2% for pure components and a mixture of similar hydrocarbons. This simple model was found to work well for the systems investigated. To apply this method to mixtures, the scaling factors were determined from a mole-fraction weighted sum of the pure-component values. The mono-variant dependence of reduced viscosity upon residual molar entropy was observed for the pure fluids investigated, and by incorporating two scaling factors (one for reduced viscosity and the other for residual molar entropy), the data were represented by a single universal curve.

The reduced viscosity was calculated according to the definition of Bell, while the residual entropy was calculated from accurate multi-parameter Helmholtz-energy equations of state and, for mixtures, the multi-fluid Helmholtz energy approximation.

The mixtures considered were octane + dodecane, decane + carbon dioxide, and 1,3-dimethylbenzene ( m-xylene) + carbon dioxide. In this work, we have investigated the mono-variant relationship between the reduced viscosity and residual entropy in pure fluids and in binary mixtures of hydrocarbons and hydrocarbons with dissolved carbon dioxide.

Highest absolute molar entropy