Determination of densities and heat capacities from speed of sound measurements for 1,1,1,2-tetrafluoroethane

New method for deriving accurate thermodynamic properties from speed-of-sound

“…Then, the derived thermodynamic properties of the IVM were compared either with direct measurements or against analytical eos, giving, by and large, a very good agreement [13][14][15]. However, it has been reported too some inaccuracies, mainly in the surface of C V;m , in the form of small ripples but large enough to be spotted at naked eye in the high density and temperature region [14].…”

“…In the past, a predictor-corrector algorithm has been enough to perform a reliable and stable integration, and the speed-of-sound required at each point of the integration was obtained by a two-dimensional interpolation of the direct measurements [13][14][15]. Then, the derived thermodynamic properties of the IVM were compared either with direct measurements or against analytical eos, giving, by and large, a very good agreement [13][14][15].…”

“…Finally, there is a numerical method in which all thermodynamic properties are derived from speed-of-sound with no approximations neither assumptions about their functional form [11][12][13][14][15]. The goal of all above methods is to exploit the great precision with which speed-of-sound measurements can be made.…”

“…Since measurements of the speed-of-sound in fluids became more and more precise, several approaches have been discussed in the literature about how to derive from these data other thermodynamic properties [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Thermodynamic Properties of Gases from Speed-of-Sound Measurements

“…For imposing Neumann conditions correctly, one needs to know the compressibility factor at least at another temperature close to the initial one, but in practice two additional temperature points are necessary. This approach was successfully applied to the determination of the density and isochoric heat capacity of HFC-134a from speed-of-sound values, in the T -ρ domain [11].…”