Heat transfer modelling during film condensation inside tubes

Abstract

In this paper, an improved analytical model for predicting heat transfer during condensation in pipes with arbitrary orientations is provided. The required dimensionless basic groups were obtained by a weak Finite Element Method (FEM) 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 model is valid for Reynolds numbers in the liquid and vapor phases ranging from 65 to 84,832 and from 890 to 594,550, respectively, an internal tube diameter range from 2 to 50 mm, steam qualities from 0,01 to 0,99, and mass flow rates from 2,9 to 852 kg/(m²•s). 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.