Correlation for forced convective boiling heat transfer of nonazeotropic refrigerant mixture of HCFC22/CFC114 in a horizontal smooth tube

Experiments are carried out on the boiling heat transfer of nonazeotropic refrigerant mixtures of HCFC22/CFC114 flowing inside a 7.9 mm ID horizontal smooth tube. Using a water-heated, double-tube type evaporator, the local heat transfer coefficients are measured for both counter and parallel flows. An empirical correlation equation is proposed for the data in the annular-flow regime, taking into account the mixture effect in the authors' previous correlation equation for pure refrigerants. The mean deviation between the calculated and measured heat transfer coefficients is 8.9% for the present experimental data and 7.1% for the data obtained by Jung. The equation reveals that the convection heat transfer is dominant due to the suppression of nucleate boiling for the mixtures.