Simulation of falling film flow and heat transfer at shell-side of coil-wound heat exchanger

The objective of this paper is to develop a numerical model to predict the two-phase flow, heat transfer and mass transfer at shell-side of coil-wound heat exchangers(CWHEs), which can predict the performance of heat exchangers and optimize the structure of CWHE. To achieve this goal, the mechanism of the status of shell-side two-phase flow should be analyzed. Then, a model for simulating flow pattern, including the droplet flow, the column flow and the sheet flow, is developed by employing the volume of fluid-continuous surface force method; the mass transfer model is developed and mass transfer rate can be predicted on tube surface and liquid-gas interface; then the latent heat during evaporation and condensation can be calculated based on the mass transfer rates; the forces and the heat and mass transfer rates are introduced into the control equations as the source terms. The proposed model is validated by the experimental data from the existing references. There is good agreement between experimental data and predictions. The validation results show that 89% of the predicted data can agree with the experimental data within a deviation of ±25%. The heat and mass transfer coefficients obtained by the model are also analyzed. © All Right Reserved.