Heat transfer correlations for evaporation of refrigerant mixtures flowing inside horizontal microfin tubes

Based on the experimental results of R417A flowing inside horizontal microfin tubes, the present work deals with the development of prediction methods for evaporation heat transfer of refrigerant mixtures in microfin tube. The microfin model by Thome et al. is modified by adjusting the convective heat transfer term, and the other microfin model is developed by introducing the enhancement factor into the modified-Kattan model. The comparison of the calculations by several microfin models and the experimental results reveals that the new microfin models developed at the present study are in much better agreement with the experimental results with the reducing average deviation by 30–50% than the models by Thome et al. and Cavallini et al., and are recommended for the prediction of evaporation heat transfer coefficients for non-azeotropic refrigerant mixtures inside microfin tubes.