In the present study, a prediction model for condensation of binary zeotropic refrigerant mixtures inside a horizontal smooth tube is proposed. In this model the following assumptions are employed : (1) The phase equilibrium is established at the vapor-liquid interface, while the bulk vapor is saturated and the bulk liquid is subcooled. (2) The heat transfer coefficients in liquid film and the frictional pressure drop are calculated by the correlations for pure refrigerants proposed by Haraguchi et al. (3) The mass transfer coefficient in the liquid film is infinite, and the mass transfer coefficient in the vapor core is estimated by a correlation that is derived from the correlation of the frictional pressure drop, based on the Chilton-Colburn analogy.<br>The predicted results are compared with the experimental ones for the condensation of HFC134a/HCFC 123 and HCFC22/CFC 114 mixtures. The predicted heat flux distribution along the tube axis is in good agreement with that of the experiment, and the calculated values of condensing length agree well with the experimental ones. Using the present model, the local mass fraction distribution, the diffusion mass flux and the mass transfer characteristics in both vapor and liquid phase are also demonstrated. From these results, the effect of mass transfer resistance on condensation heat transfer characteristics is clarified.
|Translated title of the contribution||Condensation of Binary Zeotropic Refrigerant Mixtures inside a Horizontal Smooth Tube Prediction Model for Local Characteristics of Heat and Mass Transfer|
|Number of pages||12|
|Publication status||Published - Mar 31 2000|