Thermal diffusivity and thermal conductivity of toluene by photon correlation spectroscopy: A test of the accuracy of the method

Kraft, K.; Lopes, Manuel Matos; Leipertz, Alfred

doi:10.1007/bf01441908

Cited by 37 publications

(22 citation statements)

References 9 publications

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“…The exemplarily depicted error bars for the thermal diffusivity and sound speed of SES36 in the saturated-liquid phase represent the total uncertainties, which could be estimated to be less than ±2% and ±0.5%, respectively, except for a few data points close to the critical point. The evaluation of the uncertainties is based on the standard deviation of single measurements, which may be regarded as a direct measure of the uncertainty of data by DLS from bulk fluids [26]. The larger uncertainty of the results for the thermal diffusivity of SES36 in comparison to former [23]; · · · , Chen equation ρ = f (T R , p R , ρ C ) [24,25]; − · −·, midpoints (ρ + ρ )/2; , critical point).…”

Section: Thermal Diffusivity and Sound Speedmentioning

confidence: 99%

Thermophysical Properties of a Refrigerant Mixture of R365mfc (1,1,1,3,3-Pentafluorobutane) and Galden® HT 55 (Perfluoropolyether)

Fröba

Kremer²,

Leipertz

et al. 2007

Int J Thermophys

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This work presents a comprehensive experimental study of various thermophysical properties of an azeotropic refrigerant mixture of 65 mass% R365mfc (1,1,1,3,3-pentafluorobutane) and 35 mass% Galden HT 55 (perfluoropolyether). Light scattering from bulk fluids has been applied for measuring both the thermal diffusivity and the speed of sound in the liquid and vapor phases under saturation conditions, between 293 K and the liquid-vapor critical point at 450.7 K. Furthermore, the speed of sound has been measured for the superheated-vapor phase along nine isotherms, between 393 and 523 K and up to a maximum pressure of about 2.5 MPa. For temperatures between 253 and 413 K, light scattering by surface waves on a horizontal liquid-vapor interface has been used for simultaneous determination of the surface tension and kinematic viscosity of the liquid phase. With light scattering techniques, uncertainties of less than ±2.0%, ±0.5%, ±1.5%, and ±1.5% have been achieved for the thermal diffusivity, sound speed, kinematic viscosity, and surface tension, respectively. In addition to vapor-pressure measurements between 304 and 448 K, the density was measured between 273 and 443 K using a vibrating-tube method. Here, measurements have been performed in the compressed-and saturated-liquid phases with uncertainties of ±0.3% and ±0.1%, respectively, as well as for the superheated vapor up to a maximum pressure of about 3 MPa with an uncertainty between ±0.3% and ±3%. Critical-point parameters were derived by combining the data obtained by different techniques. 449 0195-928X/07/0400-0449/0 © 2007 Springer Science+Business Media, LLC 450 Fröba, Kremer, Leipertz, Flohr, and Meurer

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Section: Thermal Diffusivity and Sound Speedmentioning

confidence: 99%

Thermophysical Properties of a Refrigerant Mixture of R365mfc (1,1,1,3,3-Pentafluorobutane) and Galden® HT 55 (Perfluoropolyether)

Fröba

Kremer²,

Leipertz

et al. 2007

Int J Thermophys

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“…2 and 3, the open symbols represent the measured values for the boiling liquid and the closed symbols those of the saturated vapor. The error bars shown for the liquid phase represent the standard deviation of single measurements, which in "conventional" DLS represents an estimate of the measurement uncertainty [15]. Except for some data near the critical point, overall uncertainties of ±1% for the thermal diffusivity of R227ea and of ±0.5% for the sound speed are estimated.…”

Section: Thermal Diffusivity and Sound Speedmentioning

confidence: 99%

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

2006

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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.

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“…The evaluation of the uncertainties is based on the standard deviation of the single measurements, which may be regarded as a direct measure of the uncertainty of data by DLS from bulk fluids [18]. Approaching the critical point, an increasing standard deviation for the thermal diffusivity and sound speed measurements of 2 and 1%, respectively, could be observed.…”

Section: Thermal Diffusivity and Sound Speedmentioning

confidence: 99%

Thermophysical Properties of a Quaternary Refrigerant Mixture: Comparison of Dynamic Light Scattering Measurements with a Simple Prediction Method

Fröba

Botero

Kremer³

et al. 2007

Int J Thermophys

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Dynamic light scattering (DLS) has been used for the measurement of several thermophysical properties of a quaternary refrigerant mixture R-125/143a/32/134a in its liquid phase under saturation conditions. The thermal diffusivity and sound speed have been obtained by light scattering from bulk fluids over a temperature range from about 293 K up to the liquid-vapor critical point. By applying the method of DLS to a liquid-vapor interface, also called surface light scattering (SLS), the saturated liquid kinematic viscosity and surface tension can be determined simultaneously. These properties have been measured from about 243 to 343 K. The results are discussed in comparison with literature data and with a simple prediction method based on the mass-weighted properties of the pure components, expressed as functions of the reduced temperature. Once again, the simple prediction method was shown to be applicable for the calculation of different transport and other thermophysical properties of multicomponent refrigerant mixtures and this with sufficiently high accuracy for technical practice. Moreover, the input data for the simple prediction scheme can be reduced without loss of accuracy by treating binary or ternary mixtures as a subset of the multicomponent mixture.

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Thermal diffusivity and thermal conductivity of toluene by photon correlation spectroscopy: A test of the accuracy of the method

Cited by 37 publications

References 9 publications

Thermophysical Properties of a Refrigerant Mixture of R365mfc (1,1,1,3,3-Pentafluorobutane) and Galden® HT 55 (Perfluoropolyether)

Thermophysical Properties of a Refrigerant Mixture of R365mfc (1,1,1,3,3-Pentafluorobutane) and Galden® HT 55 (Perfluoropolyether)

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

Thermophysical Properties of a Quaternary Refrigerant Mixture: Comparison of Dynamic Light Scattering Measurements with a Simple Prediction Method

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