The impact and freezing processes of a nanofluid droplet on an ice surface

In the present study, the impact and freezing processes of TiO2 nanofluid droplets on an ice surface were experimentally investigated. A parameter study of the volume concentration, the particle diameter, and the ice surface temperature was carefully carried out. The impact and freezing processes of de-ionized water droplets on the ice surface were also performed for comparison. The results showed that the maximum spreading factor decreased with the increase in volume concentration or the decrease in ice surface temperature. Besides, the ice bead morphologies of nanofluids on the ice surfaces could differ significantly from that of a de-ionized water droplet. Nanofluid droplets formed a crater shape with an annulus around the ice bead and a plateau in the center. The freezing times of the nanofluid droplets first decreased and then increased with the increase in volume concentration. In addition, the contact angle of the final ice bead increased with the increase in volume concentration. Moreover, the maximum spreading factor, the freezing time, and the contact angle of the final ice bead exhibited non-monotonic relationships with the particle diameter.