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  • 1
    Electronic Resource
    Electronic Resource
    Status of the round robin on the transport properties of R134a (1995)
    Springer
    International journal of thermophysics 16 (1995), S. 63-78 
    Details
    ISSN: 1572-9567
    Keywords: R134a ; dilute gas ; refrigerant ; saturation properties ; 1,1,1,2-tetrafluoroethane ; thermal conductivity ; transport properties ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The paper contains a status report on an international project coordinated by the Subcommittee on Transport Properties of Commission 1.2 of the International Union of Pure and Applied Chemistry. The project has been conducted to investigate the large discrepancies between the results reported by various authors for the transport properties of R134a. The project has involved the remeasurement of the transport properties of a single sample of R134a in nine laboratories throughout the world in order to test the hypothesis that at least part of the discrepancy could be attributed to the purity of the sample. This paper provides an intercomparison of the new experimental results obtained to data in this project for the viscosity and the thermal conductivity in both gaseous and liquid phases. The agreement between the viscosity data from the laboratories contributing to the project was improved with several techniques, now producing consistent results. This suggests that the purity of the samples of R134a used in previous work was at least partly reponsible for the discrepancies observed. For the thermal conductivity in the liquid phase the results of the measurements are also more consistent than before, although not for all experimental techniques. Not all of the previous measurements suffered from significant sample impurities, so the present measurements on a consistent high-purity sample can he used to detect data sets which are outhers, possibly because of impurities. Identification of laboratories and techniques with systematic differences may require the examination of data for several fluids. The implications for future measurements of the transport properties of other refrigerants are significant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01438958
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  • 2
    Electronic Resource
    Electronic Resource
    Density of 1,1-dichloro-1-fluoroethane (HCFC 141b) as a function of temperature and pressure (1996)
    Springer
    International journal of thermophysics 17 (1996), S. 551-560 
    Details
    ISSN: 1572-9567
    Keywords: density ; HCFC 141b ; pressure ; temperature ; Tait equation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The density of HCFC 141b has been measured at several temperatures between 260 and 320 K, Mid pressures up to 20 MPa, with a mechanical oscillator densimeter. The densimeter was calibrated with 2,2,4-trimethylpentane, whose density was obtained from a correlating cyuation with 0.3% uncertainty. The density data obtained for HCFC 14H) hits a reproducibility of 0.05% and an uncertainty of 0.3%. The data obtained were fitted to a Tait-type equation. which reproduced the experimental densities within 0.11 % and were compared with the data obtained in other works.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01441502
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  • 3
    Electronic Resource
    Electronic Resource
    The dielectric constant of liquid HFC 134a and HCFC 142b (1996)
    Springer
    International journal of thermophysics 17 (1996), S. 573-585 
    Details
    ISSN: 1572-9567
    Keywords: density ; dielectric constant ; dipole moment ; HFC 134a ; HCFC 142b ; Kirkwood equation ; refrigerant ; Vedam equation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper presents measurements of the dielectric constant of HFC 134a and HCFC 1426, as a function of pressure and temperature, in the temperature range from 200 to 300 K and pressures up to 20 M Pa, using a direct capacitance method, The samples used had a stated purity of 99.8 and 99.9%, respectively, The values of the dielectric constant have a precision of 0.01 % and an accuracy of 0.1%, The data obtained were correlated as a function of density and pressure, The theory developed by Vedam et al,, based on the Eulerian strain. and the Kirkwood equation for the variation of modified molar polarization with temperature and density were applied to analyze the data and to obtain the dipole moment of both refrigerants in the liquid state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01441504
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  • 4
    Electronic Resource
    Electronic Resource
    Radiative heat transfer in transient hot-wire measurements of thermal conductivity (1991)
    Springer
    International journal of thermophysics 12 (1991), S. 985-997 
    Details
    ISSN: 1572-9567
    Keywords: radiative heat transfer ; thermal conductivity ; toluene ; transient hot-wire technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract New measurements of the thermal conductivity of liquid toluene between 300 and 550 K have been used to study the importance of radiative heat transfer when using the transient hot-wire technique. The experimental data were used to obtain the radiation correction to the hot-wire temperature rises. Radiationcorrected values of thermal conductivity are reported. This study shows that the transient hot-wire method is much less affected by radiation than steady-state techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00503514
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  • 5
    Electronic Resource
    Electronic Resource
    Thermal conductivity surface of argon: A fresh analysis (1991)
    Springer
    International journal of thermophysics 12 (1991), S. 965-984 
    Details
    ISSN: 1572-9567
    Keywords: argon ; liquid ; supercritical ; surface fit ; thermal conductivity ; transient hot wire technique ; vapor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper presents a fresh analysis of the thermal conductivity surface of argon at temperatures between 100 and 325 K with pressures up to 70 MPa. The new analysis is justified for several reasons. First, we discovered an error in the compression-work correction, which is applied when calculating thermal conductivity and thermal diffusivity obtained with the transient hot-wire technique. The effect of the error is limited to low densities, i.e., for argon below 5 mol·L−1. The error in question centers on the volume of fluid exposed to compression work. Once corrected, the low-density data agree very well with the available theory for both dilute-gas thermal conductivity and the first density coefficient of thermal conductivity. Further, the corrected low-density data, if used in conjunction with our previously reported data for the liquid and supercritical dense-gas phases, allow us to represent the thermal conductivity in the critical region with a recently developed mode-coupling theory. Thus the new surface incorporates theoretically based expressions for the dilute-gas thermal conductivity, the first density coefficient, and the critical enhancement. The new surface exhibits a significant reduction in overall error compared to our previous surface which was entirely empirical. The uncertainty in the new thermal conductivity surface is ±2.2% at the 95% confidence level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00503513
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  • 6
    Electronic Resource
    Electronic Resource
    Mutual diffusivity of a mixture of n-hexane and nitrobenzene near its consolute point (1992)
    Springer
    International journal of thermophysics 13 (1992), S. 283-294 
    Details
    ISSN: 1572-9567
    Keywords: binary diffusion ; critical phenomena ; n-hexane ; nitrobenzene ; Taylor dispersion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is demonstrated that the Taylor dispersion method can be used to measure the mutual diffusivity of liquid mixtures near a critical mixing point. For this purpose we have measured the mutual diffusivity of a liquid mixture of n-hexane and nitrobenzene at the critical composition at temperatures from 16 K down to 1 K above the critical temperature. The results are in agreement with the theoretically predicted behavior of the diffusivity near a critical point of mixing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00504437
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  • 7
    Electronic Resource
    Electronic Resource
    Density of α-pinene, Β-pinene, limonene, and essence of turpentine (1992)
    Springer
    International journal of thermophysics 13 (1992), S. 295-301 
    Details
    ISSN: 1572-9567
    Keywords: density ; essence of turpentine ; limonene ; α-pinene ; Β-pinene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Densities of ga-pinene, Β-pinene, limonene, and essence of turpentine have been measured at 293.15, 298.15, 303.15, 308.15, and 313.15 K, at atmospheric pressure, with a mechanical oscillator densimeter. Benzene and cyclohexane were used as calibration fluids. The precision is of the order of 0.01 kg · m−3, while the accuracy is estimated to be 0.1%. A linear representation of the variation of the density with temperature reproduces the experimental data within 0.2%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00504438
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  • 8
    Electronic Resource
    Electronic Resource
    The thermal conductivity of 1-chloro-1,1-difluoroethane (HCFC-142b) (1992)
    Springer
    International journal of thermophysics 13 (1992), S. 383-399 
    Details
    ISSN: 1572-9567
    Keywords: concentric cylinder apparatus ; 1-chloro-1,1-difluoroethane ; thermal conductivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The thermal conductivity of 1-chloro-1,1-difluoroethane (HCFC-142b) has been measured in the temperature range 290 to 504 K and pressures up to 20 MPa with a concentric-cylinder apparatus operating in a steady-state mode. These temperature and pressure ranges cover all fluid states. The estimated accuracy of the method is about 2%. The density dependence of the thermal conductivity has been studied in the liquid region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00503878
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  • 9
    Electronic Resource
    Electronic Resource
    A computer-controlled instrument for the measurement of the thermal conductivity of liquids (1987)
    Springer
    International journal of thermophysics 8 (1987), S. 511-519 
    Details
    ISSN: 1572-9567
    Keywords: liquids ; measurement technique ; thermal conductivity ; toluene ; transient hot-wire method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new instrument for the measurement of the thermal conductivity of liquids by the transient hot-wire method is described. The instrument has features in common with earlier versions but employs a novel technique for the determination of the transient temperature rise of the hot wire during the course of a measurement. New determinations of the thermal conductivity of toluene confirm the accuracy of the instrument to be better than 0.5%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00503639
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  • 10
    Electronic Resource
    Electronic Resource
    Thermal diffusivity measurement by the transient hot-wire technique: A reappraisal (1988)
    Springer
    International journal of thermophysics 9 (1988), S. 293-316 
    Details
    ISSN: 1572-9567
    Keywords: argon ; thermal conductivity ; thermal diffusivity ; toluene ; transient hot-wire technique ; m-xylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The theory of the transient hot-wire technique for thermal conductivity measurements is reassessed in the special context of thermal diffusivity measurements. A careful examination of the working equation and an error analysis are employed to identify the principal sources of error. Notwithstanding earlier claims to the contrary, the best precision that can be attained in thermal diffusivity measurements is of the order of ±3%, while the accuracy is inevitably poorer. Experimental evidence is adduced from two different instruments that supports the analysis given here. Although the technique cannot yield values of the thermal diffusivity, k, as accurate as can be achieved by the use of the best possible individual values of λ,ρ, and C p in the relation k=λ/ρC p, the simplicity of the technique makes it attractive for many purposes. It is even possible to derive values of the isobaric heat capacity C p for many fluids not available from other methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00513073
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