An improved heat transfer correlation for condensation inside inclined smooth tubes

Abstract

To date, there has been no robust model that can satisfactorily predict the condensation heat transfer coefficients in smooth tubes when oriented at some angles other than horizontal and vertical. Therefore, it was the motivation of this investigation to develop a universally acceptable model capable of predicting the heat transfer coefficients during convective condensation inside inclined tubes subject to diabatic conditions. An extensive database of experimental results collected from our previous studies was used in the development of the proposed model. The database consisted of five hundred and fifty-nine data sets for tube orientation varying between - 90o and + 90o, mass velocities 100 kg/m2s to 400 kg/m2s, mean vapour qualities 10% to 90% and saturated condensing temperatures 30 °C to 50 °C. The proposed model showed a magnificient agreement with the experimental data within an global average and mean absolute deviations of −5.74% and 1.13% respectively. The performance of the new empirical model was validated with inclined flow data from three sources in the open literature and was found to predict them with high accuracy.