Heat transfer model for downward two-component two-phase flows in inclined pipes

Downward two-component two-phase flows are commonly encountered in many chemical engineering applications. Accurate prediction of the heat transfer coefficient is of great importance to the design and operation of heat transfer systems. The mechanism of two-phase heat transfer is complicated because of the complex interactions between gas and liquid phases. Therefore, this study was aimed at developing a robust and theoretically supported heat transfer coefficient correlation for downward two-component two-phase flow in inclined pipes with the extended Chilton-Colburn analogy. First, an extensive literature review was performed to collect more than 1700 experimental data for downward two-phase heat transfer coefficients in inclined pipes and 10 heat transfer coefficient correlations. Poor predictive performance of the existing correlations was identified using the whole collected database. Then, the dependence of the heat transfer coefficient on void fraction and two-phase multiplier was analyzed using the extended Chilton-Colburn analogy. The dependence of the heat transfer coefficient on the pipe inclination angle was discussed in depth. The exponents in the newly-developed heat transfer coefficient correlation were correlated in terms of the pipe inclination angle. A robust and semi-theoretically supported correlation was developed for predicting the heat transfer coefficient of downward two-component two-phase flows in inclined pipes. The mean relative deviation (bias), m_rel, and the mean absolute relative deviation (random uncertainty), m_{rel, ab}, were −4.54 % and 13.8 %, respectively. The new heat transfer coefficient correlation will be of practical importance in understanding the two-component two-phase heat transfer characteristics. © 2023 Elsevier Ltd.