Heat Transfer Modeling During Condensation Inside Tubes With Arbitrary Geometrical Orientations

ABSTRACT An improved analytical model for predicting heat exchange during condensation inside tubes with any geometric orientation is presented. The required dimensionless basic groups were obtained by a weak Finite Element Method formulation of the Green equation. The proposed model was compared with available experimental data for 22 different types of fluids, including water, organic liquids, and refrigerants. The proposed model is valid for liquid and vapor phase Reynolds numbers from 65 to 84,832 and from 890 to 594,550, respectively, a range of tube diameters from 2 to 50 mm, vapor qualities from 0.01 to 0.99, and a mass flow rate from 2.9 to 852 kg•(m 2 •s) −1 . In the comparison between the model and the experimental data it was found that the model correlates with a mean deviation of ± 10% and ± 20% in 56.3% and 93.6% of the experimental data available for horizontal tubes, and with a mean deviation of ± 10% and ± 20% in 45.9% and 92.4% of the data available for vertical and inclined tubes (downward). The results show that the model presented in this study is satisfactory, so it could be considered suitable for use in thermal engineering.