Experimental study and correlation of the thermal conductivity of 1,1,1,2-tetrafluoroethane (R134a) in the rarefied gas state

A multiparameter thermal conductivity equation for R134a with an optimized functional form

“…The vapor phase data of Tsvetkov et al [34] from a concentric-cylinder apparatus are necessary to give further experimental information about the vapor region at low temperatures, otherwise documented by only one data set. The agreement of these data with the other primary sources was evidenced in Ref.…”

Measurements of the Thermal Conductivity of HFC-134a in the Supercritical Region

“…In Table 2 are listed similar analytic equations (up to the third order) that have been reported in the literature [8][9][10][11][12][13][14][15][16] to 16 The dashed lines are one standard deviation of the fit of our complete experimental data set using eq 4 (see text). represent the temperature variation of the thermal conductivity of R134a at atmospheric pressure.…”

“…This work: ◼ (Table ) and ◆ Le Neindre and Garrabos (ref ), where the calculated values were obtained from eq . From experimental values of Table and calculated values obtained from the analytical correlations reported in Table : ×, Perkins et al; , ∗, Soldner et al; −, Krauss et al;; △, Hammerschmidt; ◻, Tsvetkov et al; +, Gross et al; ◇, Tanaka et al; ○, Yata et al The dashed lines are one standard deviation of the fit of our complete experimental data set using eq (see text).…”

“…In Table are listed similar analytic equations (up to the third order) that have been reported in the literature – to represent the temperature variation of the thermal conductivity of R134a at atmospheric pressure. The values of their adjustable coefficients are reported in column 2, while their respective temperature range of validity is given in column 3, covering then the complete temperature range from (200 to 600) K. The corresponding 1σ-standard deviation from our experimental results given in Table is reported in column 4, which clearly shows the weakness of some analytic equations. ,,, These systematic deviations of the temperature dependence of the thermal conductivity of the dilute gas are also illustrated in Figure , while this figure simultaneously reveals the noticeable agreement between the experimental data obtained by static methods. , As was mentioned in ref , the uncertainty at low densities is much larger than that at higher densities due to the large inner and outer boundary corrections in transient hot-wire measurements.…”

“…In Table are listed similar analytic equations (up to the third order) that have been reported in the literature – to represent the temperature variation of the thermal conductivity of R134a at atmospheric pressure. The values of their adjustable coefficients are reported in column 2, while their respective temperature range of validity is given in column 3, covering then the complete temperature range from (200 to 600) K. The corresponding 1σ-standard deviation from our experimental results given in Table is reported in column 4, which clearly shows the weakness of some analytic equations. ,,, These systematic deviations of the temperature dependence of the thermal conductivity of the dilute gas are also illustrated in Figure , while this figure simultaneously reveals the noticeable agreement between the experimental data obtained by static methods. , As was mentioned in ref , the uncertainty at low densities is much larger than that at higher densities due to the large inner and outer boundary corrections in transient hot-wire measurements. Therefore, Figure indicates that the experimental data generally agree with the linear correlation of eq within an uncertainty of 2σ, especially for the temperature range (300 to 600) K. Such a linear form can be of practical interest to complement our previous theoretical dilute gas function that represents λ 0 (see eqs to of ref ).…”