Measurement of liquid film thickness on the hydrophobic surfaces at the rotating vertically disc contactor

Experimentally, the research on the flow of liquid film of viscous liquid on vertically rotating flat disc partially immersed in a liquid bath has been investigated and modellelled by many researchers. The difference, in this research, the liquid being used is tap water. Meanwhile, the characteristic of disk surface chosen was hydrophobic one. The reason for this choice was due to the fact that the material being used to sell for public had hydrophobic characteristics. Therefore, for the disk material, the researcher used the material from acrylic and novotex that had hydrophobic characteristics on its surface. In addition to the disk material, also investigated the influence of surface topography, by doing three variations of topography. Furthermore, this research was conducted experimentally to see the flow characteristics of liquid film at the rotating vertically disk, especially at the low rotational speed around 1-20 rpm. The other parameter affected to the thickness characteristics of liquid film dealing with the disk depth to the water surface was also considered. Finally, the research result showed that hydrophobic surface had an effect to the flow profile and its depth of liquid film. However, liquid film was not capable of sticking very well especially at the low rotational speed of 1-7.5 rpm. Besides, the thickness profile of liquid film was not always equally the same and was not capable of achieving to the top of disk when it was rotating up.