Jet-Wiping Facility Ondule
ONDULE is a facility dedicated to the study of plane jet wiping with viscous liquids.
The facility consists in a rotating cylinder in Plexiglas dipping in a bath of liquid, such that it drags a relatively thick film. The linear substrate velocity can be varied between 0.1 and 0.6 m/s, and the working liquid is usually glycerine. One fourth of rotation after dipping, the film is wiped by a turbulent slot jet. Several nozzle geometries are available, and a displacement system allows adjusting the standoff distance from the nozzle to the substrate between 3 and 25 mm. The nozzle can also be tilted from 30° upwards to 30° downwards. The thickness and quality of the liquid film after wiping is visualized with a high-speed camera located 45° downstream the wiping zone. For that purpose, the working liquid is colored with a dye, and illuminated by a diffused light source placed inside the cylinder. The jet pressure and substrate speed are monitored using a computer acquisition system. Laser triangulation probes are also used to measure the mean film thickness. A doctor-blade cleans the cylinder surface after measurements.