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  • 1
    Electronic Resource
    Electronic Resource
    Thermal conductivity of gaseous fluorocarbon refrigerants R 12, R 13, R 22, and R 23, under pressure (1981)
    Springer
    International journal of thermophysics 2 (1981), S. 249-268 
    Details
    ISSN: 1572-9567
    Keywords: chorotrifluoromethane (R 13) ; chlorodifluoromethane (R 22) ; dichlorodifluoromethane (R 12) ; fluorocarbon ; pressure effect on thermal conductivity ; thermal conductivity ; trifluoromethane (R 23)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The thermal conductivity of four gaseous fluorocarbon refrigerants has been measured by a vertical coaxial cylinder apparatus on a relative basis. The fluorocarbon refrigerants used and the ranges of temperature and pressure covered are as follows: R 12 (Dichlorodifluoromethane CCl2F2): 298.15–393.15 K, 0.1–4.28 MPa R 13 (Chlorotrifluoromethane CClF3): 283.15–373.15 K, 0.1–6.96 MPa R 22 (Chlorodifluoromethane CHClF2): 298.15–393.15 K, 0.1–5.76 MPa R 23 (Trifluoromethane CHF3): 283.15–373.15 K, 0.1–6.96 MPa The apparatus was calibrated using Ar, N2, and CO2 as the standard gases. The uncertainty of the experimental data is estimated to be within 2%, except in the critical region. The behavior of the thermal conductivity for these fluorocarbons is quite similar; thermal conductivity increases with increasing pressure. The temperature coefficient of thermal conductivity at constant pressure, (∂λ/∂T) p , is positive at low pressures and becomes negative at high pressures. Therefore, the thermal conductivity isotherms of each refrigerant intersect each other in a specific range of pressure. A steep enhancement of thermal conductivity is observed near the critical point. The experimental results are statistically analyzed and the thermal conductivities are expressed as functions of temperature and pressure and of temperature and density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00504188
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  • 2
    Electronic Resource
    Electronic Resource
    Thermal conductivity of liquid halogenated ethanes under high pressures (1988)
    Springer
    International journal of thermophysics 9 (1988), S. 465-479 
    Details
    ISSN: 1572-9567
    Keywords: fluorocarbon ; halogenated ethane ; liquid ; high pressure ; refrigerant ; thermal conductivity ; transient hot-wire method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract New experimental data on the thermal conductivity of liquid halogenated ethanes, R112 (CCl2F-CCl2F), R113 (CCl2F-CClF2), R114 (CClF2-CClF2), R114B2 (CBrF2-CBrF2), and R123 (CHCl2-CF3), are presented in the temperature range from 283 to 348 K at pressures up to 200 MPa or the freezing pressures. The measurements were carried out by a transient hot-wire apparatus within an uncertainty of ±1.0%. The thermal conductivity data obtained have been analyzed by means of the corresponding-states principle and other empirical methods. It is found that the corresponding-states correlation λ=f(Tr, Pr) holds well for R112, R113, and R114. The thermal conductivity can also be correlated satisfactorily with temperature, pressure, and molar volume by a similar expression to the Tait equation and the dense hard-sphere model presented by Dymond.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00503147
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  • 3
    Electronic Resource
    Electronic Resource
    A new correlation for the viscosity of gaseous fluorocarbon refrigerants (1986)
    Springer
    International journal of thermophysics 7 (1986), S. 1023-1031 
    Details
    ISSN: 1572-9567
    Keywords: dimensional analysis ; fluorocarbon ; gas mixture ; generalized correlation ; principle of corresponding states ; refrigerant ; viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A new generalized correlation is presented for the low-pressure gaseous viscosity of fluorocarbon refrigerants. The following empirical equation is obtained based on the most reliable experimental data for 16 fluorocarbons: $$\eta \xi = \left( {0.5124T_r - 0.0517} \right)^{0.82} Z_c ^{ - 0.81}$$ where η is the viscosity in μPa·s and ξ is the viscosity parameter defined using the critical temperature T c in K, the critical pressure P c in MPa, and the molar mass M in g·mol−1 as follows: $$\xi = T_c ^{1/6} M^{ - 1/2} P_c ^{ - 2/3}$$ The applicable ranges are 0.6〈T r〈1.8 and 0.253〈Z c〈0.282. The availability of the correlating equation for both pure fluorocarbons and their mixtures has been investigated based on the experimental data of these authors and those in the literature. It is found that the present correlation is useful for the prediction of the viscosity of pure fluorocarbons and their binary mixtures at atmospheric pressure with mean deviations less than 1.6%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00502375
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