Abstract

This paper deals with the change in contact angle of droplets for three nanofluids, i.e., water-Al₂O₃, water-TiO₂ and water-Cu. Nanoparticles were tested at the concentration of 0.01, 0.1, and 1% by weight. Although dispersants were not used to stabilize the suspension, the solutions tested exhibited satisfactory stability. Ultrasonic vibration was used in order to stabilise the dispersion of the nanoparticles. Experimental measurements were performed for horizontal stainless steel (316) tube of three diameters, i.e., 1.6, 3 and 5 mm, and flat stainless steel plates. The results obtained show that the contact angle of tested nanofluids depends strongly on nanoparticle concentration as well as the curvature of the substrate