Investigation of mist cooling impact on heat exchanger performance based on experimental and numerical simulation studies

In this study, the effect of mist cooling on the performance of a heat exchanger was investigated through the measurements of airflow temperature during mist injection, numerical simulation, and comparison of overall heat transfer coefficients. The experimental results showed that the effectiveness of mist cooling was affected by the ambient conditions, and a temperature drop of several degrees Celsius was actually achieved. Because the Stokes number of the mist particles in this study was very small, the numerical simulation results showed that the mist concentration downstream of the nozzle position increased, resulting in a larger temperature drop in the central area of wind tunnel. In conclusion, the overall heat transfer coefficient successfully increased by a maximum of 1.48 times due to the mist injection. Obtained results suggested that if the mist could be dispersed more uniformly, and reach the heat transfer surface in liquid phase without forming a liquid film, the heat exchange performance would be further improved.