Newtonian and viscoelastic liquid jet impingement on a moving surface

Motivated by the need to improve transfer efficiencies of liquid coatings from jet impingement in railroad friction control applications, an experimental investigation into Newtonian and viscoelastic liquid jet impingement on moving surfaces is presented. Seven PEO-glycerine-water solutions and three commercial liquid friction modifiers were tested with a variety of jet speeds, jet diameters, surface speeds and surface roughnesses. The effects of these test conditions on jet impingement splash behaviours as well as jet and lamella geometries were studied. High-speed imaging was employed to visualize the interaction between the impinging jet and the moving surface. Experiments on the effect of modest surface roughness revealed that, while jet and surface speed were both important factors, splash was more likely to occur on surfaces with lower roughness levels. By analyzing experimental results for Newtonian liquids, a relation between lamella geometry and test conditions were found, which can be used to predict lamella dimensions. Three types of non-Newtonian behaviours were observed at high surface speed and low jet speed: jet necking, jet bending and jet stretching.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat