Enhancement of heat exchanges on a condenser using an air flow containing water droplets

A study has been carried out on the enhancement of the heat exchanged on a tube and fin exchanger using an air flow containing water droplets. An experimental setup has been used, which consists of a channel where an air flow with droplets is crossing a heat exchanger fed with water. A model representing the heat transfer has been presented and validated using the experimental data. The heat exchange improvement obtained thanks to the injection of droplets in the air upstream to the heat exchanger has been quantified. The cooling of air due to water evaporation upstream to the exchanger and the supplementary evaporation of droplets while impacting or crossing the exchanger leads to an enhanced heat exchange. A gain by a factor up to 3.5 has been observed in the heat flux exchanged in the most favoring case, when comparing the heat flux exchanged using a simple air flow or air containing droplets. No streaming water has been observed in the present study owing to the droplet injection conditions: moderate water flow and droplet size near 25 μm at the injection point.