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

A Multiparameter Thermal Conductivity Equation for 1,1-Difluoroethane (R152a) with an Optimized Functional Form

“…(5) is sufficient for a satisfactory representation of the critical enhancement part of the thermal conductivity. This statement is confirmed by the results obtained for R134a [5], for carbon dioxide [15], and for the present fluid, as evidenced in the following.…”

“…(5), empirically obtained with a trial-and-error procedure of regression on generated data of different fluids, is sufficiently flexible to follow the data trends, and it was already applied with satisfying results for the cases of R134a [5] and carbon dioxide [15]. The parameters a and the multiplying coefficient n c are regressed during the fitting procedure from experimental data of the target fluid.…”

“…A brief summary of the different approaches reported in the literature for the representation of the transport properties was presented in previous studies [4,5]. In particular, the state-of-the-art technique for the development of dedicated transport property equations is noted here.…”

“…As alternatives to the conventional procedure, some totally correlative techniques were also developed [3][4][5][8][9][10][11][12][13][14][15]. Among the others, the technique for optimizing the functional form of multiparameter equations of state, developed by Setzmann and Wagner [16], proved to be a powerful function approximator suitable to develop a transport property equation directly from the experimental data.…”

“…Among the others, the technique for optimizing the functional form of multiparameter equations of state, developed by Setzmann and Wagner [16], proved to be a powerful function approximator suitable to develop a transport property equation directly from the experimental data. The method was previously used with successful results for the modeling of viscosity [3,4,14] and of thermal conductivity [5,15], and the present work deals with the application of this modeling technique to the thermal conductivity representation of R152a. For the sake of precision, it should be noted that the algorithm of Setzmann and Wagner was already applied to transport property modeling of oxygen in 1990 [7], but in that case the model format and its representation capability were completely different from the present one.…”