LAUSR

Abstract The falling film flow has gained wide attention in recent years, due to its extraordinary performance in different heat exchangers in terms of high heat transfer coefficient and low energy consumption. In this paper, a series of experiments are conducted in a smooth tube and a finned tube respectively, in order to investigate the heat transfer characteristics of the cooling falling film flow outside vertical tubes in open rack vaporizer (ORV). Different control variables affecting the heat transfer characteristics are studied, including the mass flow rate and the temperature of water, the heat flux and the tube shape. The experimental data are compared with the predicted values from existing correlations, and all of them show large discrepancies. Therefore, a new correlation is proposed to accurately predict the heat transfer coefficient of the falling film flow based on the experimental data. The predicted values of the new correlation are within an error band of 10% of the experimental data. The study may provide reference for the research on the falling film flow and effective design and operation of ORV.