Enhanced dropwise condensation by oil infused nano-grass coatings on outer surface of a horizontal copper tube

In this paper, a quick and easy method to fabricate oil infused nanograss (OIN) thin hydrophobic films for dropwise condensation enhancement is presented. Droplet sliding experiments on an inclined surface coated with this thin film infused with oil show that the droplet dripping rate can be increased considerably. Experiments of condensation heat transfer on the outer surface of a cold tube with this OIN coating show that heat transfer can be enhanced up to approximately 50% compared to raw copper surface. The enhanced condensation heat transfer by OIN coatings is due to the combination of dropwise condensation and faster removal of water droplets.