Thermal Diffusivity, Sound Speed, Viscosity, and Surface Tension of R227ea (1,1,1,2,3,3,3-Heptafluoropropane)

Abstract

The purpose of the experimental investigations described in the present paper was to carry out an extensive characterization of R227ea (1,1,1,2,3,3,3-heptafluoropropane), a working fluid that has gained increasing importance in refrigeration and air conditioning technology fields. With dynamic light scattering (DLS), a non-intrusive, laser-optical technique, the thermal diffusivity and sound speed of the liquid and vapor phases, as well as the surface tension and kinematic viscosity of the liquid phase, could be determined with high accuracy at saturation conditions, over a wide temperature range starting at 253.15 K and extending to the critical point.

Modified PT-LJ-SAFT Density Functional Theory

“…These irregularities can be found on all different length scales and they can be described by thermally excited surface waves (TF) having a wide spectrum of wave length. The existence of these "ripplons" is used in surface light scattering (SLS) by Fröba et al [93][94][95] for an accurate measurement of surface tension of pure fluids over a wide temperature range. This surface roughening leads to an increase in the effective interfacial thickness and thus affects the interfacial tension.…”

Liquid Viscosity and Surface Tension ofn-Hexane,n-Octane,n-Decane, andn-Hexadecane up to 573 K by Surface Light Scattering

“…During the last two decades, research activities at the Department of Chemical and Biological Engineering (CBI) and at the Erlangen Graduate School in Advanced Optical Technologies (SAOT) of the Friedrich-Alexander-University Erlangen-Nürnberg (FAU) developed SLS as a reliable and accurate instrument in thermophysical property research of fluids covering broad ranges of viscosity and surface or interfacial tension. For various systems at the vapor–liquid equilibrium, for example, reference fluids (toluene, diisodecyl phthalate, carbon dioxide, and n -pentane), refrigerants, ,, hydrofluoroethers, ionic liquids, − linear and branched alkanes as well as mixtures of n -alkanes with other n -alkanes , or oxygenated derivatives, viscosity and surface or interfacial tension have been determined with typical measurement uncertainties ( k = 2) below 2% at temperatures between 233 and 573 K. For binary model systems, the simultaneous analysis of fluctuations at the surface and in the bulk of the fluid allowed for the determination of interfacial tension, viscosity, thermal diffusivity, and mutual diffusivity of the very same sample within one single SLS setup . Recently, we demonstrated the applicability of SLS for the investigation of multiphase systems in the vapor–liquid–liquid equilibrium, simultaneously measuring the viscosities of the two liquid phases and the vapor–liquid and liquid–liquid interfacial tensions …”

Liquid Viscosity and Surface Tension of n-Dodecane, n-Octacosane, Their Mixtures, and a Wax between 323 and 573 K by Surface Light Scattering

“…All these features allow for defining the method as a quasi-primary method for the measurement of viscosity . During the past two decades, our research activities were devoted to developing a proper execution of SLS for a routine measurement of surface tension and liquid viscosity with high accuracy for fluids with relatively low viscosity, such as refrigerants, − hydrofluoroethers, or toluene, the latter data which served as reference for the development of a low-viscosity standard . In a second step, our investigations could demonstrate that the SLS technique constitutes also a valuable tool for thermophysical property research of high-viscosity fluids in the form of ionic liquids − or the reference substance diisodecyl phthalate …”