Thermal conductivity, estimation

The uncertainties of the equation of state are approximately 0.2% (to 0.5% at high pressures) in density, 1% (in the vapor phase) to 2% in heat capacity, 1% (in the vapor phase) to 2% in the speed of sound, and 0.2% in vapor pressure, except in the critical region. For viscosity, estimated uncertainty is 2%. For thermal conductivity, estimated uncertainty, except near the critical region, is 4-6%. 

Liquids The Baroncini method provides accurate liquid thermal conductivity estimates if the compound clearly belongs to one of the specific families designated by the correlation. The Sastri-Rao method is recommended for other specific families as listed in the discussion of the method given below. As a general method for estimating thermal conductivity of pure liquids at ambient pressure for all other compounds, the Missenard method is recommended. 

Annie Paul et al. [36] studied short randomly oriented PP/banana fibre composites. The thermophysical properties of the above composites were studied on the basis of different banana fibre loading and different chemical treatments given to the banana fibres. The incorporation of banana fibres into PP matrix induced a decrease of the effective thermal conductivity of the composite. The use of the theoretical series conduction model allowed to estimate the transverse thermal conductivity of untreated banana fibre composites. As was expected, the series model appears sufficient for the effective thermal conductivity estimation of this kind of composites. All the chemical treatments enhanced both thermal conductivity and diffusivity of the composite considerably in varying degrees. This indicates that the chemical treatment allows a better contact between the fibre and the matrix and reduces considerably the thermal contact resistance. Nevertheless, a significant increase of the thermal conductivity was observed only for benzoylated and 10% NaOH-treated fibre composites. Besides, the variations of density and specific heat upon fibre chemical treatment are small compared to their associated uncertainties. 

Thermophysical Property Estimation. For pure components there is not a large difference in thermophysical properties estimated by different methods except for thermal conductivity of water. The main problem is the thermal conductivity estimation of mixtures.The method of Friend and Adler (15) is suitable due to its simplicity. However, the method of Mason and Saxena as given by Touloukiau (26) estimates higher thermal conductivities and requires larger computation time than the previous method but seems to be more accurate. 

The third column uses Mason and Saxena method(26) for mixture thermal conductivity estimations. The fourth column gives the results for the simplified reaction model and thermal physical properties of the mixture. In this run, the first two reactions are considered in the five reaction model of Sundaram and Froment (22), Thus, the following two reaction model, given below, give reasonably accurate results. 

Barroncini, C. R, Di Filippo, R. Latini, G. (1983b). Thermal conductivity estimation of the organic and inorganic refrigerants in the saturated liquid state. Int. J. Rrfrig., 6,60-67. 

HeXe gas mixture thermal conductivity estimates are not as consistent as the mixture viscosity estimates and do not compare as well to empirical data. TTie Wassiljewa formnlation and the method of Chnng were veiy inaccurate. The Chapman (DIPPR) method stayed within 5.7% of INL provided empirical data, while the Mason (DIPPR) method was less accurate. 

Gegenhnber, N., Schon, J.H., 2014. Thermal conductivity estimation from elastic wave velocity— appUcation of a petrographic coded modeL Petrophysics 55, 51-56. 

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