The effect of ionisation of spray in cooling air on the wetting characteristics of finned tube heat exchanger

A major concern when introducing a water spray to pre-cool the air flowing into a finned tube heat exchanger is that wetting of the heat exchanger surface may cause corrosion. In an attempt to prevent droplets from impacting and wetting the heat exchanger, the use of an electrostatically charged spray was investigated. Experiments were performed whereby electrostatically charged spray was sprayed on a heat exchanger with an electric charge having the same polarity as the droplets. The results indicated that droplet deposition decreased significantly as the charge on the droplets was increased. However, total prevention of deposition could not be achieved, since the equipment used could not produce high enough voltages. This concept shows some promise, and it is recommended that further research be performed on it.