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Multiparameter Equations of State for Selected Siloxanes



P. Colonna, R. Nannan, A. Guardone, Eric Lemmon


The development of technical equations of state using the 12-parameter Span-Wagner functional form for four siloxanes is presented in two parts. The fluids under investigation include hexamethyldisiloxane (MM), tetradecamethylhexasiloxane (MD4M), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). Siloxanes are used as heat transfer fluids and working media in energy conversion applications. In part I, available properties are critically evaluated and selected for the optimization of the equation of state parameters. Due to the insufficient number of available measurements, several other properties are estimated with the most accurate ad hoc methods. These estimates are then used in the optimization of the equation of state (EoS) parameters. Moreover, experimental saturated liquid density and vapor pressure data are correlated with the equations proposed by Daubert and Wagner-Ambrose, respectively, to provide short, simple and accurate equations for the computation of these properties. The performance of the mentioned equations of state is illustrated in the second part of this article.
Fluid Phase Equilibria


Caloric Properties, Critical Point, D4, D5, Density, Equation of State, Fundamental Equation, MD4M, MM, Siloxane, Thermodynamic Properties, Vapor Pressure


Colonna, P. , Nannan, R. , Guardone, A. and Lemmon, E. (2006), Multiparameter Equations of State for Selected Siloxanes, Fluid Phase Equilibria, [online], (Accessed May 24, 2024)


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Created April 24, 2006, Updated October 12, 2021