Analysis of evaporation of non-azeotropic refrigerants in a horizontal tube

Based on the two-phase separated model, a detailed one-dimensional model for binary mixtures had been proposed to study the in-tube evaporation in a horizontal tube. The present model can predict the detailed variation of the composition, temperature, heat transfer rate and pressure drop of various binary mixtures under constant heat flux, counter-flow, or parallel-flow conditions. The predicted results agree favorably with the Takamatsu et al. [Int. J. Heat Transfer 36, 3555-3563 (1993)] and Jung et al. [Exp. Heat Transfer 2, 237-255 (1989)] experimental data. Also, it is found that the full evaporation of the non-azeotropic refrigerants may require a corresponding temperature higher than the saturation temperature of the less volatile component. The non-linear variation of the property plays an important role in the heat transfer and pressure drop characteristics of the refrigerant mixtures.