Numerical investigation on saturated boiling and heat transfer correlations in a vertical rectangular mini-channel

In order to understand the phenomenon of saturated boiling heat transfer in a vertical rectangular mini-channel of the plate-fin heat exchanger (PFHE), the saturated boiling mechanism was investigated by ANSYS CFX based on the model which was validated by the experimental data from literature and the heat transfer correlation by Liu and Winterton's model was improved in terms of the experimental data from literature. The results showed that the deviation between simulation results and experiments is within ±15%. According to the simulation results, the main boiling mechanism is forced convective boiling for saturated boiling heat transfer at high vapor quality while the contribution of nucleate boiling is slight. At the same time, the evaporation of dispersed liquid phase should make the essential contribution to heat transfer. The improved correlation in terms of the experimental data from literature is in good agreement with the simulation results. The deviation between correlation calculations and simulation results is less than ±30%. These results will provide some constructive instructions for the understanding of saturated boiling phenomenon in a vertical rectangular mini-channel, and for the design and prediction of heat transfer performance in PFHE. (authors)