Experimental and Theoretical Study on Condensation Heat Transfer of Nonazeotropic Refrigerant Mixtures R1234yf/R32 Inside a Horizontal Smooth Tube

The condensation heat transfer characteristics of nonazeotropic mixtures R1234yf and R32 (mass fractions of 0.52:0.48 and 0.77:0.23, respectively) inside a horizontal smooth tube (inner diameter 4 mm) were experimentally studied at mass fluxes ranging from 100 to 300 kg/m s. A prediction model for the forced convective condensation heat transfer characteristics of nonazeotropic refrigerant mixtures was also constructed based on the measured results, and the details are presented. The heat transfer characteristics, especially the heat transfer deterioration of the nonazeotropic refrigerant mixture, are evaluated by combining the correlations of heat transfer and mass transfer at both the vapor side and liquid side. By comparison with experimental data, prediction results obtained using the proposed model were found to agree reasonably with the experimental condensation heat transfer coefficient of binary refrigerant mixtures using R1234yf and R32.